Lung mucosal immunity to NTHi vaccine antigens: Antibodies in sputum of chronic obstructive pulmonary disease patients.

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory illness in older adults. A major cause of COPD-related morbidity and mortality is acute exacerbation of COPD (AECOPD). Bacteria in the lungs play a role in exacerbation development, and the most common pathogen is non-typeable Haemophilus influenzae (NTHi). A vaccine to prevent AECOPD containing NTHi surface antigens was tested in a clinical trial. This study measured IgG and IgA against NTHi vaccine antigens in sputum. Sputum samples from 40 COPD patients vaccinated with the NTHi vaccine were collected at baseline and 30 days after the second dose. IgG and IgA antibodies against the target antigens and albumin were analyzed in the sputum. We compared antibody signals before and after vaccination, analyzed correlation with disease severity and between sputum and serum samples, and assessed transudation. Antigen-specific IgG were absent before vaccination and present with high titers after vaccination. Antigen-specific IgA before and after vaccination were low but significantly different for two antigens. IgG correlated between sputum and serum, and between sputum and disease severity. Sputum albumin was higher in patients with severe COPD than in those with moderate COPD, suggesting changes in transudation played a role. We demonstrated that immunization with the NTHi vaccine induces antigen-specific antibodies in sputum. The correlation between IgG from sputum and serum and the presence of albumin in the sputum of severe COPD patients suggested transudation of antibodies from the serum to the lungs, although local IgG production could not be excluded.Clinical Trial Registration: NCT02075541.

What is the context? Chronic obstructive pulmonary disease (COPD) is the most common chronic respiratory illness in older adults and the third leading cause of death worldwide.One bacterium in the lungs, non-typeable Haemophilus influenzae (NTHi), is responsible for acute exacerbation of the disease, characterized by an increase in airway wall inflammation and symptoms, leading to high morbidity and mortality.A vaccine targeting NTHi was previously developed but did not show efficacy in reducing exacerbations in COPD patients, probably because the vaccine did not elicit an immune response in the lung mucosae, where the bacteria are located.What is the impact? Parenteral immunization with new vaccines targeting NTHi is able to elicit immune defense at the level of lung mucosae.Now that antibodies can be measured in sputum, new vaccines against COPD exacerbations or other lung infections can be tested for efficacy in the actual target tissue.Also, lung immunity against specific pathogens can now be tested.What is new? We determined that antigen-specific antibodies were present in the lungs after vaccination; these were assessed in sputum after vaccination with NTHi surface antigens.NTHi-specific IgG were present in the lungs and appeared to have arrived there primarily by transudation, a type of leakage from the serum to the lung mucosae.Transudation appeared to be stronger in severe than in moderate COPD patients.

Co-immunization with DNA vaccines encoding yidR and IL-17 augments host immune response against Klebsiella pneumoniae infection in mouse model.

Klebsiella pneumoniae is an important gram-negative bacterium that causes severe respiratory and healthcare-associated infections. Although antibiotic therapy is applied to treat severe infections caused by K. pneumoniae, drug-resistant isolates pose a huge challenge to clinical practices owing to adverse reactions and the mismanagement of antibiotics. Several studies have attempted to develop vaccines against K. pneumoniae, but there are no licensed vaccines available for the control of K. pneumoniae infection. In the current study, we constructed a novel DNA vaccine, pVAX1-YidR, which encodes a highly conserved virulence factor YidR and a recombinant expression plasmid pVAX1-IL-17 encoding Interleukin-17 (IL-17) as a molecular adjuvant. Adaptive immune responses were assessed in immunized mice to compare the immunogenicity of the different vaccine schemes. The results showed that the targeted antigen gene was expressed in HEK293T cells using an immunofluorescence assay. Mice immunized with pVAX1-YidR elicited a high level of antibodies, induced strong cellular immune responses, and protected mice from K. pneumoniae challenge. Notably, co-immunization with pVAX1-YidR and pVAX1-IL-17 significantly augmented host adaptive immune responses and provided better protection against K. pneumoniae infections in vaccinated mice. Our study demonstrates that combined DNA vaccines and molecular adjuvants is a promising strategy to develop efficacious antibacterial vaccines against K. pneumoniae infections.

Outer membrane vesicles derived from Bordetella pertussis are potent adjuvant that drive Th1-biased response.

For several years, we have been committed to exploring the potential of Bordetella pertussis-derived outer membrane vesicles (OMVBp) as a promising third-generation vaccine against the reemerging pertussis disease. The results of our preclinical trials not only confirm its protective capacity against B. pertussis infection but also set the stage for forthcoming human clinical trials. This study delves into the examination of OMVBp as an adjuvant. To accomplish this objective, we implemented a two-dose murine schedule to evaluate the specific immune response induced by formulations containing OMVBp combined with 3 heterologous immunogens: Tetanus toxoid (T), Diphtheria toxoid (D), and the SARS-CoV-2 Spike protein (S). The specific levels of IgG, IgG1, and IgG2a triggered by the different tested formulations were evaluated using ELISA in dose-response assays for OMVBp and the immunogens at varying levels. These assays demonstrated that OMVBp exhibits adjuvant properties even at the low concentration employed (1.5 µg of protein per dose). As this effect was notably enhanced at medium (3 µg) and high concentrations (6 µg), we chose the medium concentration to determine the minimum immunogen dose at which the OMV adjuvant properties are significantly evident. These assays demonstrated that OMVBp exhibits adjuvant properties even at the lowest concentration tested for each immunogen. In the presence of OMVBp, specific IgG levels detected for the lowest amount of antigen tested increased by 2.5 to 10 fold compared to those found in animals immunized with formulations containing adjuvant-free antigens (p<0.0001). When assessing the adjuvant properties of OMVBp compared to the widely recognized adjuvant alum, we detected similar levels of specific IgG against D, T and S for both adjuvants. Experiments with OMVs derived from E. coli (OMVE.coli) reaffirmed that the adjuvant properties of OMVs extend across different bacterial species. Nonetheless, it's crucial to highlight that OMVBp notably skewed the immune response towards a Th1 profile (p<0.05). These collective findings emphasize the dual role of OMVBp as both an adjuvant and modulator of the immune response, positioning it favorably for incorporation into combined vaccine formulations.

Causal relationships of Helicobacter pylori and related gastrointestinal diseases on Type 2 diabetes: Univariable and Multivariable Mendelian randomization.

BACKGROUND: Previous observational studies have demonstrated a connection between the risk of Type 2 diabetes mellitus (T2DM) and gastrointestinal problems brought on by Helicobacter pylori (H. pylori) infection. However, little is understood about how these factors impact on T2DM. METHOD: This study used data from the GWAS database on H. pylori antibodies, gastroduodenal ulcers, chronic gastritis, gastric cancer, T2DM and information on potential mediators: obesity, glycosylated hemoglobin (HbA1c) and blood glucose levels. Using univariate Mendelian randomization (MR) and multivariate MR (MVMR) analyses to evaluate the relationship between H. pylori and associated gastrointestinal diseases with the risk of developing of T2DM and explore the presence of mediators to ascertain the probable mechanisms. RESULTS: Genetic evidence suggests that H. pylori IgG antibody (P = 0.006, b = 0.0945, OR = 1.0995, 95% CI = 1.023-1.176), H. pylori GroEL antibody (P = 0.028, OR = 1.033, 95% CI = 1.004-1.064), gastroduodenal ulcers (P = 0.019, OR = 1.036, 95% CI = 1.006-1.068) and chronic gastritis (P = 0.005, OR = 1.042, 95% CI = 1.012-1.074) are all linked to an increased risk of T2DM, additionally, H. pylori IgG antibody is associated with obesity (P = 0.034, OR = 1.03, 95% CI = 1.002-1.055). The results of MVMR showed that the pathogenic relationship between H. pylori GroEL antibody and gastroduodenal ulcer in T2DM is mediated by blood glucose level and obesity, respectively. CONCLUSION: Our study found that H. pylori IgG antibody, H. pylori GroEL antibody, gastroduodenal ulcer and chronic gastritis are all related to t T2DM, and blood glucose level and obesity mediate the development of H. pylori GroEL antibody and gastroduodenal ulcer on T2DM, respectively. These findings may inform new prevention and intervention strategies for T2DM.

Investigation of the safety and protective efficacy of an attenuated and marker M. bovis-BoHV-1 combined vaccine in bovines.

Bovine respiratory disease (BRD) is one of the most common diseases in the cattle industry worldwide; it is caused by multiple bacterial or viral coinfections, of which Mycoplasma bovis (M. bovis) and bovine herpesvirus type 1 (BoHV-1) are the most notable pathogens. Although live vaccines have demonstrated better efficacy against BRD induced by both pathogens, there are no combined live and marker vaccines. Therefore, we developed an attenuated and marker M. bovis-BoHV-1 combined vaccine based on the M. bovis HB150 and BoHV-1 gG-/tk- strain previously constructed in our lab and evaluated in rabbits. This study aimed to further evaluate its safety and protective efficacy in cattle using different antigen ratios. After immunization, all vaccinated cattle had a normal rectal temperature and mental status without respiratory symptoms. CD4+, CD8+, and CD19+ cells significantly increased in immunized cattle and induced higher humoral and cellular immune responses, and the expression of key cytokines such as IL-4, IL-12, TNF-α, and IFN-γ can be promoted after vaccination. The 1.0 × 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 BoHV-1 gG-/tk- combined strain elicited the most antibodies while significantly increasing IgG and cellular immunity after challenge. In conclusion, the M. bovis HB150 and BoHV-1 gG-/tk- combined strain was clinically safe and protective in calves; the mix of 1.0 × 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 BoHV-1 gG-/tk- strain was most promising due to its low amount of shedding and highest humoral and cellular immune responses compared with others. This study introduces an M. bovis-BoHV-1 combined vaccine for application in the cattle industry.

Diagnostic accuracy of DPP Fever Panel II Asia tests for tropical fever diagnosis.

BACKGROUND: Fever is the most frequent symptom in patients seeking care in South and Southeast Asia. The introduction of rapid diagnostic tests (RDTs) for malaria continues to drive patient management and care. Malaria-negative cases are commonly treated with antibiotics without confirmation of bacteraemia. Conventional laboratory tests for differential diagnosis require skilled staff and appropriate access to healthcare facilities. In addition, introducing single-disease RDTs instead of conventional laboratory tests remains costly. To overcome some of the delivery challenges of multiple separate tests, a multiplexed RDT with the capacity to diagnose a diverse range of tropical fevers would be a cost-effective solution. In this study, a multiplex lateral flow immunoassay (DPP Fever Panel II Assay) that can detect serum immunoglobulin M (IgM) and specific microbial antigens of common fever agents in Asia (Orientia tsutsugamushi, Rickettsia typhi, Leptospira spp., Burkholderia pseudomallei, Dengue virus, Chikungunya virus, and Zika virus), was evaluated. METHODOLOGY/PRINCIPAL FINDINGS: Whole blood (WB) and serum samples from 300 patients with undefined febrile illness (UFI) recruited in Vientiane, Laos PDR were tested using the DPP Fever Panel II, which consists of an Antibody panel and Antigen panel. To compare reader performance, results were recorded using two DPP readers, DPP Micro Reader (Micro Reader 1) and DPP Micro Reader Next Generation (Micro Reader 2). WB and serum samples were run on the same fever panel and read on both micro readers in order to compare results. ROC analysis and equal variance analysis were performed to inform the diagnostic validity of the test compared against the respective reference standards of each fever agent (S1 Table). Overall better AUC values were observed in whole blood results. No significant difference in AUC performance was observed when comparing whole blood and serum sample testing, except for when testing for R. typhi IgM (p = 0.04), Leptospira IgM (p = 0.02), and Dengue IgG (p = 0.03). Linear regression depicted R2 values had ~70% agreement across WB and serum samples, except when testing for leptospirosis and Zika, where the R2 values were 0.37 and 0.47, respectively. No significant difference was observed between the performance of Micro Reader 1 and Micro Reader 2, except when testing for the following pathogens: Zika IgM, Zika IgG, and B pseudomallei CPS Ag. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that the diagnostic accuracy of the DPP Fever Panel II is comparable to that of commonly used RDTs. The optimal cut-off would depend on the use of the test and the desired sensitivity and specificity. Further studies are required to authenticate the use of these cut-offs in other endemic regions. This multiplex RDT offers diagnostic benefits in areas with limited access to healthcare and has the potential to improve field testing capacities. This could improve tropical fever management and reduce the public health burden in endemic low-resource areas.

Quantitative analysis of pertussis, tetanus, and diphtheria antibodies in sera and breast milk from Tdap vaccinated women using a qualified multiplex assay.

Pertussis (whooping cough) is a reemergent, highly contagious respiratory infection of public health concern. Infants prior to initiation of their primary vaccination series are the most vulnerable to severe infection, and even death. Vaccination during pregnancy is an efficacious means of reducing infection in infants. This approach relies on boosting maternal immunity and passive transfer of antibodies to the infant via placenta and breast milk. Similarly, maternal vaccination post-partum can enhance maternal-infant immunity. To support the analysis of pertussis immunity in the context of maternal-infant immunization, we developed a high throughput multiplex assay for simultaneous quantification of serum IgG antibodies against pertussis vaccine antigens: pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM2/3), and against tetanus (TT) and diphtheria toxoids (DT), using the Meso Scale Discovery (MSD) platform. The assay was qualified, and specificity, sensitivity, accuracy, precision, linearity, and robustness were demonstrated. The assay was subsequently adapted for quantification of IgG and IgA in breast milk. Applied to a serological survey of pregnant women living in the United States and sub-Saharan Africa, this method revealed differences in magnitude and breadth of antibody profile, consistent with history of vaccination. A longitudinal analysis of Tdap responses in women vaccinated post-partum demonstrated a rapid increase in serum IgG that remained elevated for up to 24 months. Likewise, high levels of vaccine-specific IgA and IgG antibodies were present in breast milk, although they exhibited faster decay. This multiplex MSD assay is a reliable and practical tool for quantification of pertussis, tetanus, and diphtheria antibodies in serum and breast milk in serosurveys or vaccine studies. IMPORTANCE: Pertussis (whooping cough) has reemerged in recent years. Vaccination during pregnancy is an effective approach to prevent illness during the first months of life. We developed a multiplex assay for quantification of pertussis, tetanus, and diphtheria serum antibodies using the Meso Scale Discovery (MSD) platform; the method was qualified, and specificity, precision, accuracy, linearity, and limits of quantification were defined. It was also adapted for quantification of antibodies in breast milk. We successfully determined serostatus in women from different regions and with different vaccination histories, as well as responses to Tdap in blood and breast milk post-partum. This is the first description of a multiplex assay for the quantification of pertussis, tetanus, and diphtheria antibodies in breast milk.

Risk of cardiac conduction disorders, and pacemaker implantations among individuals tested for serum Borrelia burgdorferi antibodies, a nationwide, matched, population-based cohort study.

OBJECTIVES: To investigate the short- and long-term risks of atrioventricular block and other cardiac conduction disorders associated with being tested for Borrelia burgdorferi (Bb) antibodies or Bb seropositivity as measures of confounding by indication and Bb infection, respectively. METHODS: We performed a nationwide population-based matched cohort study (Denmark, 1993-2021). We included 52 200 Bb-seropositive individuals (stratified as only Bb-IgM-seropositive [n = 26 103], only Bb-IgG-seropositive [n = 18 698], and Bb-IgM-and-IgG-seropositive [n = 7399]) and two age- and sex-matched comparison cohorts: 104 400 Bb-seronegative individuals and 261 000 population controls. We investigated the risk associated with being tested for serum Bb antibodies and being Bb seropositive. Outcomes were atrioventricular block and other conduction disorders. We calculated short-term odds ratios (aOR) (within 1 month), and long-term hazard ratios (aHR) (after 1 month) adjusted for age, sex, diabetes, chronic heart failure, and kidney disease with 95% CI. RESULTS: Compared with population controls, individuals tested for Bb antibodies had increased short- and long-term risks of atrioventricular block (aOR 47.9, 95% CI: 30.0-76.7, aHR 1.3, 95% CI:1.2-1.3), and other conduction disorders (aOR 18.2, 95% CI: 10.1-32.8, aHR 1.2, 95% CI: 1.1-1.4). Compared with Bb-seronegative individuals, only Bb-IgM-and-IgG-seropositive individuals had increased short-term risk of atrioventricular block (aOR: 2.1, 95% CI: 1.5-3.1). DISCUSSION: The results suggest that Bb antibody testing is included in the diagnostic work-up of conduction disorders. Finally, that Bb seropositivity is not associated with other conduction disorders than atrioventricular block or with increased long-term risk of conduction disorders.

Utility of Borrelia-specific IgM and IgG antibody titer determinations during a 12-year period - results from a clinical laboratory in Northern Sweden.

Interpretation of serological findings in suspected Lyme borreliosis (LB) is challenging and IgM reactivities may have low predictive value. Therefore, if used indiscriminately, there is a risk for incorrect diagnosis of LB. To evaluate the usefulness of IgM titer determination, we performed a study of the prevalence of Borrelia-specific antibodies in serological samples from patients with suspected LB analyzed during the period 2010 - 2021 at the University Hospital of Umeå in Sweden. In total, 19,335 samples had been analyzed for the presence of IgG and IgM antibodies. Overall, there were higher percentages of IgM positive or borderline titers, 1,847 (9.6%) and 905 (4.7%), respectively, than IgG positive or borderline titers, 959 (5.0%) and 406 (2.1%), respectively. Peak number of samples were recorded 2012 - 2013, exceeding 1,800, whereas there were around 1,200 during 2020 - 2021. The peak number of positive IgG and/or positive IgM samples were observed during the period 2015 - 2017 with close to, or above 400, and concomitantly, the proportion of IgG positive samples increased markedly. For IgG positive samples, the increase followed a positive linear time trend (P< 0.001). Peak monthly numbers were observed during August, September, and October. This seasonal increase was significant for the IgG positive group (P< 0.05), but not for the IgM positive/IgG negative group. Repeated samples were obtained from 3,188 individuals and of the initial samples 2,817 were (88%) IgG negative and 2,315 (72%) were IgM negative and of these, 130 (4%) showed IgG seroconversion and 300 (9%) IgM seroconversion. Collectively, the data demonstrate that IgG and/or IgM positive samples represented a minority of all samples, even when repeated sampling had occurred, and IgM positive samples were much more common than IgG positive samples. Thus, the accuracy of the clinical suspicion was low and this will lead to a low predictive value of the analysis, in particular of IgM. These findings question the use of IgM titer determination as a routine analysis.

Proof of concept for multiplex detection of antibodies against Chlamydia species in chicken serum using a bead-based suspension array with peptides as antigens.

The available differentiating tests for Chlamydia are based on detection of genetic material and only give information about the actual infection status, but reveal nothing of past infections. As the use of serological methods increases the window of detection, the goal of this study was to investigate if it is possible to develop a differentiating serological test for antibodies against Chlamydia species in chicken sera. Focus was on C. psittaci, C. gallinacea, and two closely related species, i.e. C. abortus and C. avium. To enable differentiating serology, a bead-based Luminex suspension array was constructed, using peptides as antigens, derived from known immunoreactive Chlamydia proteins. For the majority of these peptides, species-specific seroreactivity in mammalian sera has been reported in literature. The suspension array correctly identified antibodies against various Chlamydia species in sera from experimentally infected mice, and was also able to differentiate between antibodies against C. psittaci and C. gallinacea in sera from experimentally infected chickens. In field sera, signals were difficult to interpret as insufficient sera from experimentally infected chickens were available for evaluating the seroreactivity of all peptides. Nevertheless, results of the suspension array with field sera are supported by published data on the occurrence of C. gallinacea in Dutch layers, thereby demonstrating the proof of concept of multiplex serology for Chlamydial species in poultry.

Reported History of Measles and Long-term Impact on Tetanus Antibody Detected in Children 9-59 Months of Age and Receiving 3 Doses of Tetanus Vaccine in the Democratic Republic of the Congo.

BACKGROUND: Recent studies suggest measles-induced immune amnesia could have long-term immunosuppressive effects via preferential depletion of memory CD150+ lymphocytes, and associations with a 2-3 year period of increased mortality and morbidity from infectious diseases other than measles has been shown in children from wealthy and low-income countries. To further examine the associations previous measles virus infection may have on immunologic memory among children in the Democratic Republic of the Congo (DRC), we assessed tetanus antibody levels among fully vaccinated children, with and without a history of measles. METHODS: We assessed 711 children 9-59 months of age whose mothers were selected for interview in the 2013-2014 DRC Demographic and Health Survey. History of measles was obtained by maternal report and classification of children who had measles in the past was completed using maternal recall and measles IgG serostatus obtained from a multiplex chemiluminescent automated immunoassay dried blood spot analysis. Tetanus IgG antibody serostatus was similarly obtained. A logistic regression model was used to identify association of measles and other predictors with subprotective tetanus IgG antibody. RESULTS: Subprotective geometric mean concentration tetanus IgG antibody values were seen among fully vaccinated children 9-59 months of age, who had a history of measles. Controlling for potential confounding variables, children classified as measles cases were less likely to have seroprotective tetanus toxoid antibody (odds ratio: 0.21; 95% confidence interval: 0.08-0.55) compared with children who had not had measles. CONCLUSIONS: History of measles was associated with subprotective tetanus antibody among this sample of children in the DRC who were 9-59 months of age and fully vaccinated against tetanus.

Seroprevalence of scrub typhus and other rickettsial diseases among the household rodents of Mizoram, North-East India.

In the last decade, scrub typhus, a zoonotic disease has emerged as a major health concern in Mizoram, a North-East Indian state that shares international borders with Myanmar and Bangladesh. Mizoram is a biodiversity hotspot and >85% of the state is under forest cover, which provides an ideal ecological niche for the rodents and mites to transmit scrub typhus and other rickettsial infections. Using the Weil-Felix test, a serosurvey of household rodents from 41 villages spread across all the 11 districts in Mizoram was undertaken to gather important insights on their role in disease transmission. Furthermore, the chigger and flea indexes were calculated from the captured rodents. The 163 rodents captured belonged to five species; the highest numbers were from Rattus tanezumi (87), followed by Rattus rattus (41), Mus musculus (17), Suncus murinus (16), and Bandicota bengalensis (2). The rickettsial seropositivity of the captured rodents was 66.26% (108 out of 163 were positive). Among the 163 rodents, sera of 75 (46.01%), 61 (37.42%), and 73 (44.78%) were reactive to OXK, OX19, and OX2 antigens, respectively. The chigger and flea index were 17.92 and 0.16, respectively. Overall, the study has given important insights into the risk of multiple rickettsial infections that household rodents could transmit in Mizoram. These findings indicate the need for the urgent implementation of effective rodent control strategies in Mizoram.

New Rapid Helicobacter Pylori Blood Test Based on Dual Detection of FliD and CagA Antibodies for On-Site Testing.

Helicobacter pylori is the most prevalent bacterial infection, affecting half of the world's population, with a high morbidity and mortality rate.1,2 Several invasive and noninvasive testing procedures are available, and their selective use serves the specific needs of diverse clinical scenarios. For gastric cancer prevention, mass screening is necessary and requires a noninvasive, rapid, accurate and cost-effective test. For this purpose H pylori serology currently seems to be the preferred noninvasive diagnostic method. Population-based testing and treatment for H pylori is cost effective in high-risk countries, but less effective in low- and medium-risk countries.3,4 Many serologic tests are available on the market, with inconsistent performance often being observed. Therefore, international guidelines recommend considering only serologic tests with high accuracy that have been validated in the respective local populations. To date, no rapid point-of-care test (POCT) has reached a sufficient degree of accuracy.

Seroprevalence of Helicobacter pylori infections in children and adults in Poland in the years 2020-2023.

Introduction: Helicobacter pylori is a common cause of gastrointestinal infections in people around the world. Various microbiological methods are used in the laboratory diagnosis of infections, including determining the presence of specific antibodies in the serum. Serological tests can also be used in epidemiological studies aimed at determining the incidence of H. pylori infections. Objective: The aim of the study was to obtain insight into the incidence of antibodies to H. pylori in subjects of different ages living in Poland in the years 2020-2023. Material and methods: The research used serum samples obtained between January 2020 and September 2023 from 600 subjects living in Poland. The Anti-Helicobacter pylori ELISA IgG enzyme immunoassay from Euroimmun was used to test the level of IgG antibodies to H. pylori antigens. Additionally, selected serum samples were tested for the presence of antibodies to the most important protein virulence factors of H. pylori by Western Blot. Results: IgG antibodies to H. pylori, at a diagnostically significant level, were detected in 28.3% of the examined persons. Antibodies to H. pylori were least frequently detected in children under 10 years of age (12.1%) and teenagers (13.2%). In adults aged 20 to 50, these antibodies were more common (23.9% to 29.5%). Statistically, H. pylori antibodies were most often detected in subjects over 50 years of age (52.3%). There were no statistically significant differences in the frequency of antibodies to H. pylori depending on the gender of the examined persons. In most serum samples tested by Western Blot, the presence of antibodies to the CagA protein was detected (66.7%). Conclusions: The conducted research and analysis of literature data showed a similar percentage of serum samples with a diagnostically significant level of antibodies to H. pylori in people living in Poland as in people living in other European countries. The epidemiology of infections is also very similar, characterized by low morbidity in children and adolescents and an increase in the incidence of infections with the age of the examined persons. Importantly, compared to research conducted in our country several years ago, the percentage of positive results is much lower, which may be due to the improvement of social and living conditions and hygiene habits.

An observational, cohort, multi-centre, open label phase IV extension study comparing preschool DTAP-IPV booster vaccine responses in children whose mothers were randomised to one of two pertussis-containing vaccines or received no pertussis-containing vaccine in pregnancy in England.

An antenatal pertussis vaccination programme was introduced in 2012 in the UK in the context of a national outbreak of pertussis. It has been shown that a lower antibody response to primary immunisation can be seen for certain pertussis antigens in infants born to women who received pertussis-containing antenatal vaccines, a phenomenon known as blunting. The longer-term impact of this has not been documented previously, and accordingly was evaluated in this study. Children were predominantly recruited from a previous study in which their mothers had received acellular pertussis-containing antenatal vaccines (dTaP3-IPV [diphtheria toxoid, tetanus toxoid, three antigen acellular pertussis and inactivated polio] or dTaP5-IPV [diphtheria toxoid, tetanus toxoid, five antigen acellular pertussis and inactivated polio]), or no pertussis-containing vaccine. Blood samples were obtained prior to and one month after the acellular pertussis-containing preschool booster (dTaP5-IPV) was given at around age 3 years 4 months. Pre- and post-booster immunoglobulin G (IgG) geometric mean concentrations (GMCs) against pertussis toxin, filamentous haemagglutinin, fimbriae 2 & 3, and pertactin, were compared. Prior to the receipt of the preschool booster, there was no difference in the IgG GMCs against pertussis-specific antigens between children born to women vaccinated with dTaP3-IPV and dTaP5-IPV; however, IgG GMCs against pertussis toxin were significantly lower in children born to women vaccinated with dTaP3-IPV compared with children born to unvaccinated women (geometric mean ratio 0.42 [95 % CI 0.22-0.78], p = 0.03). One month after the receipt of the preschool booster there was no differences between the groups. The blunting effect of antenatal pertussis vaccine on pertussis responses in children can persist until preschool age, although it is overcome by the administration of a booster dose. ClinicalTrials.gov registration number: NCT03578120.

Survey for Leptospira and Brucella in Amazonian manatees, Amazon river dolphins, and a tucuxi in the Brazilian Amazon.

Leptospirosis and brucellosis are zoonotic diseases with global distributions that represent severe hazards to humans and animals. We investigated exposure to Leptospira spp. and Brucella spp. in samples from Amazonian manatees Trichechus inunguis, Amazon river dolphins Inia geoffrensis, and a tucuxi Sotalia fluviatilis. The animals were free-ranging or undergoing in situ rehabilitation in the mid-Solimões River region, Brazilian Amazon. Serum samples from 19 Amazonian manatees were tested by microscopic agglutination test, Rose Bengal test, and 2-mercaptoethanol Brucella agglutination test. Antibodies against Leptospira spp. were detected in 63% of the manatees tested and serovar Patoc was considered the infecting serovar in all positive samples. Titers were generally low, indicating chronic exposure, but higher titers indicative of an active infection were detected in 3 animals. Anti-Brucella spp. antibodies were not detected. Tissue and/or body fluid samples from 12 Amazon river dolphins, a tucuxi, and 2 Amazonian manatees were investigated by multiplex PCR and bacteriology for Leptospira spp. and Brucella spp. All samples were negative. However, Enterococcus faecalis was isolated from uterine fluid, lymph node, and lung of 3 Amazon river dolphins. Bacillus spp. were isolated from milk and synovial fluid from 2 Amazon river dolphins and from a milk sample from 1 Amazonian manatee. Knowledge of the pathogens present in Amazonian manatees, Amazon river dolphins, and tucuxis is of great relevance to species conservation and environmental health. Although no clinical signs were noted, further research is needed to elucidate the clinical relevance of infection by Leptospira sp. serovar Patoc in Amazonian aquatic mammals.

Remodeling Yersinia pseudotuberculosis to generate a highly immunogenic outer membrane vesicle vaccine against pneumonic plague.

SignificanceYersinia pestis, the etiologic agent of plague, has been responsible for high mortality in several epidemics throughout human history. This plague bacillus has been used as a biological weapon during human history and is currently one of the deadliest biological threats. Currently, no licensed plague vaccines are available in the Western world. Since an array of immunogens are enclosed in outer membrane vesicles (OMVs), immune responses elicited by OMVs against a diverse range of antigens may reduce the likelihood of antigen circumvention. Therefore, self-adjuvanting OMVs from a remodeled Yersinia pseudotuberculosis strain as a type of plague vaccine could diversify prophylactic choices and solve current vaccine limitations.

Intrathecal Synthesis Index of Specific Anti-Treponema IgG: a New Tool for the Diagnosis of Neurosyphilis.

Neurosyphilis (NS) diagnosis is challenging because clinical signs are diverse and unspecific, and a sensitive and specific laboratory test is lacking. We tested the performance of an antibody index (AI) for intrathecal synthesis of specific anti-Treponema IgG by enzyme-linked immunosorbent assay (ELISA) for NS diagnosis. We conducted a retroprospective monocentric study including adults with neurological symptoms who had serum and cerebral spinal fluid (CSF) samples collected between 2006 and 2021. Two NS definitions were used. NS1 included patients with neurological symptoms, positive Treponema pallidum particle agglutination (TPPA) serology, and CSF-TPPA of ≥320, as well as CSF-leukocytes of >5 cells/mm3 and/or CSF-protein of >0.45 g/L and/or a reactive CSF-VDRL/RPR test. NS2 included patients with acute ocular and/or otologic symptoms, positive TPPA serology, and a response to NS treatment. Controls were patients with central nervous system disorders other than neurosyphilis. Anti-Treponema pallidum IgG were measured simultaneously in serum and CSF, and AI was calculated according to Reiber diagram. We assessed the AI test area under the curve (AUC), sensitivity/specificity, and estimated positive and negative predictive values. In total, 16 NS1 patients, 11 NS2 patients, and 71 controls were included. With an AI of ≥1.7 as a positive test for NS diagnostic, specificity was 98.6% (95% confidence interval [CI 95%] of 92.4 to 100.0) and sensitivity was 81.3% (CI 95% of 54.4 to 96.0) for NS1 and 98.6% (CI 95% 92.4 to 100.0) and 27.3% (CI 95% 6.0 to 61.0), respectively, for NS2. Positive and negative predictive values were >95% for NS1 and >85% for NS2, for prevalence above and below 20%. Measuring an AI for intrathecal synthesis of specific anti-Treponema pallidum IgG is a new promising tool highly specific for NS diagnosis. IMPORTANCE In the context of a lack of a gold standard for the diagnosis of neurosyphilis due to either nonspecific or nonsensitive tests, we present in this article a new promising tool highly specific for NS diagnosis. This new test involves measuring an intrathecal synthesis index of specific anti-Treponema IgG by ELISA.

A multi-epitope fusion antigen candidate vaccine for Enterotoxigenic Escherichia coli is protective against strain B7A colonization in a rabbit model.

Enterotoxigenic Escherichia coli (ETEC) strains are a leading cause of children's and travelers' diarrhea. Developing effective vaccines against this heterologous group has proven difficult due to the varied nature of toxins and adhesins that determine their pathology. A multivalent candidate vaccine was developed using a multi-epitope fusion antigen (MEFA) vaccinology platform and shown to effectively elicit broad protective antibody responses in mice and pigs. However, direct protection against ETEC colonization of the small intestine was not measured in these systems. Colonization of ETEC strains is known to be a determining factor in disease outcomes and is adhesin-dependent. In this study, we developed a non-surgical rabbit colonization model to study immune protection against ETEC colonization in rabbits. We tested the ability for the MEFA-based vaccine adhesin antigen, in combination with dmLT adjuvant, to induce broad immune responses and to protect from ETEC colonization of the rabbit small intestine. Our results indicate that the candidate vaccine MEFA antigen elicits antibodies in rabbits that react to seven adhesins included in its construction and protects against colonization of a challenge strain that consistently colonized naïve rabbits.

Compensatory intestinal antibody response against pro-inflammatory microbiota after bariatric surgery.

Obesity and type 2 diabetes (T2D) are growing burdens for individuals and the health-care system. Bariatric surgery is an efficient, but drastic treatment to reduce body weight, normalize glucose values, and reduce low-grade inflammation. The gut microbiome, which is in part controlled by intestinal antibodies, such as IgA, is involved in the development of both conditions. Knowledge of the effect of bariatric surgery on systemic and intestinal antibody response is limited. Here, we determined the fecal antibody and gut microbiome response in 40 T2D and non-diabetic (ND) obese individuals that underwent bariatric surgery (N = 40). Body weight, fasting glucose concentrations and inflammatory parameters decreased after bariatric surgery, whereas pro-inflammatory bacterial species such as lipopolysaccharide (LPS), and flagellin increased in the feces. Simultaneously, concentrations of LPS- and flagellin-specific intestinal IgA levels increased with the majority of pro-inflammatory bacteria coated with IgA after surgery. Finally, serum antibodies decreased in both groups, along with a lower inflammatory tone. We conclude that intestinal rearrangement by bariatric surgery leads to expansion of typical pro-inflammatory bacteria, which may be compensated by an improved antibody response. Although further evidence and mechanistic insights are needed, we postulate that this apparent compensatory antibody response might help to reduce systemic inflammation by neutralizing intestinal immunogenic components and thereby enhance intestinal barrier function after bariatric surgery.