Vectored immunoprophylaxis and treatment of SARS-CoV-2 infection in a preclinical model.

Vectored immunoprophylaxis was first developed as a means of establishing engineered immunity to HIV using an adenoassociated viral vector expressing a broadly neutralizing antibody. We applied this concept to establish long-term prophylaxis against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a mouse model using adenoassociated virus and lentiviral vectors expressing a high-affinity angiotensin-converting enzyme 2 (ACE2) decoy. Administration of decoy-expressing (adenoassociated virus) AAV2.retro and AAV6.2 vectors by intranasal instillation or intramuscular injection protected mice against high-titered SARS-CoV-2 infection. AAV and lentiviral vectored immunoprophylaxis was durable and was active against SARS-CoV-2 Omicron subvariants. The AAV vectors were also effective therapeutically when administered postinfection. Vectored immunoprophylaxis could be of value for immunocompromised individuals for whom vaccination is not practical and as a means to rapidly establish protection from infection. Unlike monoclonal antibody therapy, the approach is expected to remain active despite continued evolution viral variants.

Rh immune globulin immunoprophylaxis after RhD-positive red cell exposure in RhD-negative patients via transfusion: A survey of practices.

BACKGROUND: Current Association for the Advancement of Blood & Biotherapies (AABB) standards require transfusion services to have a policy on Rh immune globulin (RhIG) immunoprophylaxis for when RhD-negative patients are exposed to RhD-positive red cells. This is a survey of AABB-accredited transfusion services in the United States (US) regarding institutional policies and practices on RhIG immunoprophylaxis after RhD-negative patients receive RhD-positive (i.e., RhD-incompatible) packed red blood cell (pRBC) and platelet transfusions. RESULTS: Approximately half of the respondents (50.4%, 116/230) have policies on RhIG administration after RhD-incompatible pRBC and platelet transfusions, while others had policies for only pRBC (13.5%, 31/230) or only platelet (17.8%, 41/230) transfusions, but not both. In contrast, 18.3% (42/230) report that their institution has no written policies on RhIG immunoprophylaxis after RhD-incompatible transfusions. Most institutions (70.2%, 99/141) do not have policies addressing safety parameters to mitigate the risk of hemolysis associated with the high dose of RhIG required to prevent RhD alloimmunization after RhD-incompatible pRBC transfusions. DISCUSSION: With approximately half of US AABB-accredited institutions report having policies on RhIG immunoprophylaxis after both RhD-incompatible pRBC and platelet transfusions, some institutions may not be in compliance with AABB standards. Further, most with policies on RhIG immunoprophylaxis after RhD-incompatible pRBC transfusion do not have written safeguards to mitigate the risk of hemolysis associated with the high dose of RhIG required. CONCLUSION: This survey underscores the diverse and inadequate institutional policies on RhIG immunoprophylaxis after RhD exposure in Rh-negative patients via transfusion. This observation identifies an opportunity to improve transfusion safety.

Society for Maternal-Fetal Medicine Consult Series #69: Hepatitis B in pregnancy: updated guidelines.

More than 290 million people worldwide, and almost 2 million people in the United States, are infected with hepatitis B virus, which can lead to chronic hepatitis B, a vaccine-preventable communicable disease. The prevalence of chronic hepatitis B infection in pregnancy is estimated to be 0.7% to 0.9% in the United States, with >25,000 infants born annually at risk for chronic infection due to perinatal transmission. Given the burden of disease associated with chronic hepatitis B infection, recent national guidance has expanded both the indications for screening for hepatitis B infection and immunity and the indications for vaccination. The purpose of this document is to aid clinicians caring for pregnant patients in screening for hepatitis B infection and immunity status, discuss the perinatal risks of hepatitis B infection in pregnancy, determine whether treatment is indicated for maternal or perinatal indications, and recommend hepatitis B vaccination among susceptible patients. The following are the Society for Maternal-Fetal Medicine recommendations: (1) we recommend triple-panel testing (hepatitis B surface antigen screening, antibody to hepatitis B surface antigen, and total antibody to hepatitis B core antigen) at the initial prenatal visit if not previously documented or known to have been performed (GRADE 1C); (2) we recommend universal hepatitis B surface antigen screening alone at the initial prenatal care visit for all pregnancies where there has been a previously documented negative triple-panel test (GRADE 1B); (3) we recommend that individuals with unknown hepatitis B surface antigen screening status be tested on any presentation for care in pregnancy; we also recommend that those with clinical hepatitis or those with risk factors for acute hepatitis B infection be tested at the time of admission to a birthing facility when delivery is anticipated (GRADE 1B); (4) we do not recommend altering routine intrapartum care in individuals chronically infected with hepatitis B; administration of neonatal immunoprophylaxis is standard of care in these situations (GRADE 1B); (5) we do not recommend cesarean delivery for the sole indication of reducing perinatal hepatitis B virus transmission (GRADE 1B); (6) we recommend that individuals with HBV infection can breastfeed as long as the infant has received immunoprophylaxis at birth (GRADE 1C); (7) we suggest individuals with hepatitis B infection who desire invasive testing may have the procedure performed after an informed discussion on risks and benefits in the context of shared decision-making and in the context of how testing will affect clinical care (GRADE 2C); (8) in individuals with hepatitis viral loads >200,000 IU/mL (>5.3 log 10 IU/mL), we recommend antiretroviral therapy with tenofovir (tenofovir alafenamide at 25 mg daily or tenofovir disoproxil fumarate at 300 mg daily) in the third trimester (initiated at 28-32 weeks of gestation) as an adjunctive strategy to immunoprophylaxis to reduce perinatal transmission (GRADE 1B); (9) we recommend administering hepatitis B vaccine and hepatitis B immunoglobin within 12 hours of birth to all newborns of hepatitis B surface antigen-positive pregnant patients or those with unknown or undocumented hepatitis B surface antigen status, regardless of whether antiviral therapy has been given during the pregnancy to the pregnant patient (GRADE 1B); and (10) we recommend hepatitis B vaccination in pregnancy for all individuals without serologic evidence of immunity or documented history of vaccination (GRADE 1C).

Lessons learnt on infectious bronchitis virus lineage GI-23.

Infectious bronchitis virus (IBV) is the first coronavirus discovered in the world in the early 1930s and despite decades of extensive immunoprophylaxis efforts, it remains a major health concern to poultry producers worldwide. Rapid evolution due to large poultry population sizes coupled with high mutation and recombination events and the reliance of the antiviral immune response on specific antibodies against the epitopes of the S1 glycoprotein, render the control of IBV extremely challenging. The numerous and rapidly evolving genetic and antigenic IBV types are currently classified based on the whole S1 gene sequence, into 36 lineages clustered in eight genotypes. Most lineages (29) are grouped in genotype I (GI). "Variant 2" (Israel/Variant 2/1998) is the prototype strain of lineage GI-23 and, since this lineage emerged during the mid-1990s in the Middle East, it has evolved into numerous genetically related strains and disseminated to five continents. The hallmarks of IBV Variant 2-like strain infections are high virulence and remarkable nephrotropism and nephropathogenicity; however, the molecular mechanisms of these traits remain to be elucidated. Limited protection from previously utilized vaccine strains and accumulated losses to poultry producers have urged the development and implementation of homologous Variant 2-like vaccine strains. The latest avian coronavirus biology with specific emphasis on the cumulative knowledge about IBV "Variant 2" and emergence of related strains, characteristics and control are reviewed.

Early estimates of nirsevimab immunoprophylaxis effectiveness against hospital admission for respiratory syncytial virus lower respiratory tract infections in infants, Spain, October 2023 to January 2024.

The monoclonal antibody nirsevimab was at least 70% effective in preventing hospitalisations in infants with lower respiratory tract infections (LRTI) positive for respiratory syncytial virus (RSV) in Spain (Oct 2023-Jan 2024), where a universal immunisation programme began late September (coverage range: 79-99%). High protection was confirmed by two methodological designs (screening and test-negative) in a multicentre active surveillance in nine hospitals in three regions. No protection against RSV-negative LRTI-hospitalisations was shown. These interim results could guide public-health decision-making.

AAV-Vectored Expression of Marburg Virus-Neutralizing Antibody MR191 Provides Complete Protection From Challenge in a Guinea Pig Model.

Although there are no approved countermeasures available to prevent or treat disease caused by Marburg virus (MARV), potently neutralizing monoclonal antibodies (mAbs) derived from B cells of human survivors have been identified. One such mAb, MR191, has been shown to provide complete protection against MARV in nonhuman primates. We previously demonstrated that prophylactic administration of an adeno-associated virus (AAV) expressing MR191 protected mice from MARV. Here, we modified the AAV-MR191 coding sequence to enhance efficacy and reevaluated protection in a guinea pig model. Remarkably, 4 different variants of AAV-MR191 provided complete protection against MARV, despite administration 90 days prior to challenge. Based on superior expression kinetics, AAV-MR191-io2, was selected for evaluation in a dose-reduction experiment. The highest dose provided 100% protection, while a lower dose provided ∼88% protection. These data confirm the efficacy of AAV-mediated expression of MR191 and support the further development of this promising MARV countermeasure.

[On the issue of qualitative assessment of level of population commitment to vaccination].

This article presents analysis of results of quantitative study "Level of Commitment to Vaccination" based on author's original methodology of survey. The main medical and social causes of decreasing of level of population commitment to vaccination are explained. The purpose of the study is to quantitatively assess commitment to vaccination, to establish both dependence of level of commitment on risk factors of population refusal to be vaccinated and medical and social causes of this phenomenon. Materials and methods. In April-June 2023, sociological survey of respondents (n=300) aged from 19 to 75 years using the author's methodology was implemented. The statistical processing of materials was carried out using statistical software SPSS Statistics 23.0 using correlation analysis and descriptive statistics. The results and discussion. Using correlation analysis (according r-Spearman), dependence of level of commitment on number of medical and social factors was established. The readiness to vaccination depends on degree of trust to medicine. The accessibility of information about National Vaccination Calendar, vaccination scheme and vaccine effectiveness directly impact decision to be vaccinated. Conclusion. The development of complex of measures (technologies) improving population literacy through organization of informational and educational environment will reduce the number of unjustified refusals and increase level of population commitment to vaccination in general.

Characterization of Hepatitis B Virus in Tenofovir-Treated and Untreated Chronically Infected Mothers and Their Immunoprophylaxis Failure Infants.

BACKGROUND: Maternal tenofovir disoproxil fumarate (TDF) therapy during late pregnancy can reduce mother-to-infant transmission of hepatitis B virus (HBV). We investigated HBV mutations associated with maternal TDF therapy and their role in infant immunonophylaxis failure (IPF). METHODS: Serum samples from untreated (n = 89) and TDF-treated (n = 68), highly viremic, chronically infected mothers and their infants were analyzed for HBV DNA by nested polymerase chain reaction (PCR) and direct sequencing. RESULTS: At delivery, compared with untreated mothers, TDF-treated mothers had a lower HBV DNA titer and a higher frequency of basal core promoter (BCP) gene mutations, but they had similar frequencies in pre-S/S and pre-core/core mutations. The 14 mothers harboring surface "a" determinant mutants did not transmit the mutants to their immunized infants. Such mutants were found in 3 of 13 IPF infants; the 13 mothers had wild-type hepatitis B surface antigen (HBsAg). In univariable analysis, maternal HBV DNA titer (odds ratio [OR]: 1.54; 95% confidence intervals [CI]: 1.02-2.33; P = .039), genotype C (OR: 4.18; 95% CI: 1.28-13.62; P = .018) and pre-S1 wild-type sequence (OR: 6.33; 95% CI: 1.85-21.68; P = .003) at delivery were associated with infant IPF. Multivariable analyses showed that maternal genotype C (OR: 3.71; 95% CI: 1.11-12.36; P = .033) and pre-S1 wild-type (OR: 6.34; 95% CI: 1.79-22.44; P = .004) were associated with infant IPF independently of maternal viremia. CONCLUSIONS: Along with high maternal HBV DNA titer at delivery, maternal genotype C and pre-S1 wild-type sequence were potential risk factors for infant IPF, although BCP mutations were not. The offspring of pregnant women harboring "a" determinant mutants as major strains seemed to be protected by immunoprophylaxis. CLINICAL TRIALS REGISTRATION: NCT01312012.

Vertical transmission of hepatitis B virus from father to child: what can be concluded about this possibility?

Vertical hepatitis B virus (HBV) transmission is defined as transmission that occurs during pregnancy or postpartum from an HBV-infected mother to her fetus or child. It is an efficient route for the spread of HBV and is responsible for most of the cases of chronic HBV infection in adults. During pregnancy, vertical transmission can occur in the intrauterine phase, by placental infection via peripheral blood mononuclear cells, by placental leakage, or through female germ cells.The detection of HBV DNA in semen and spermatids from HBV-infected men has provided strong evidence that the male genital tract may act as a reservoir of the virus in HBV-infected men, supporting the possibility that vertical HBV transmission from an HBV-infected father to his child may also occur via the germ line at the time of fertilization, as occurs in HBV transmission from mother to child. Furthermore, it has been shown that integration of the HBV genome into the sperm cell genome can compromise sperm morphology and function and even cause hereditary or congenital biological effects in the offspring when an HBV-infected sperm fuses with an ovum.Since vertical HBV transmission from father to child can be a topic of interest and of global importance for controlling the spread of HBV, this article addresses the evidence supporting its occurrence via germ cells, the biological impact of integration of the HBV genome into the male germ cell genome, and the role of maternal immunoprophylaxis in vertical HBV transmission from father to child.

Early lessons from the implementation of universal respiratory syncytial virus prophylaxis in infants with long-acting monoclonal antibodies, Galicia, Spain, September and October 2023.

A monoclonal antibody for universal respiratory syncytial virus prophylaxis in infants has recently been licensed. We share our experiences of integrating nirsevimab into the regional immunisation programme in Galicia, Spain. After a 3-week hospital-based immunisation campaign with flexible individualised appointments and educational activities, nirsevimab uptake was 97.5% in the high-risk group, 81.4% in the catch-up group and 92.6% in infants born during the campaign. This successful implementation strategy can serve as a model and may inform other countries' programmatic deliberations.

The efficacy of combined immunotherapy with Propes and Inflamafertin in adult patients with genetic deficiency of the folate cycle and selective deficiency of NK and NKT cells.

The purpose of the present study is to evaluate the efficacy of combination immunotherapy with Propes and Inflamafertin in GDFC adults with natural killer (NK) and/or natural killer T-lymphocyte (NKT) cell deficiency. This single-centre, retrospective, controlled, non-randomized clinical trial analysed medical records of 212 adult GDFC patients aged 19-50 years (study group [SG]). SG received Propes at a dose of 2 ml intramuscularly every other day at night for three consecutive months and Inflamafertin at a dose of 2 ml IM every other day at night for three consecutive months in rotation with Propes. The control group involved 34 patients with GDFC who followed the same age and gender distribution pattern but did not receive immunotherapy. The number of NK cells reached the lower limit of normal in 95 out of 131 patients (72% of cases) with baseline deficiency of these lymphocytes. The average number of NK cells in the blood of SG patients almost doubled during the 3-month course of immunotherapy (P ˂ 0.05; Z ˂ Z0.05 ). However, it almost returned to initial levels 2 months following the discontinuation of the immunotherapeutic agents (P ˃ 0.05; Z ˃ Z0.05 ). Combination immunotherapy with Propes and Inflamafertin is an effective strategy for the treatment of immunodeficiency caused by GDFC in adult patients.

Utilization of chronic lung disease treatment before the respiratory syncytial virus season as palivizumab prophylaxis qualifier in the American Academy of Pediatrics Guidelines.

Guidelines from the American Academy of Pediatrics recommend palivizumab immunoprophylaxis for children with CLD in their second year of life if they continue to need treatment within 6 months before the RSV season. The utilization patterns of treatment (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) are not well understood. We examined variations in CLD treatment for ten consecutive 20-day segments preceding RSV season onset. Among infants and children with CLD (n = 19,026), 35.2% received one or more medical treatments for CLD any time within 200 days before entering the second RSV season: 8.6%, 3.2%, and 29.7% received supplemental oxygen, diuretics, and corticosteroids, respectively. Utilization decreased as infants' age increased with corticosteroids surpassing oxygen and diuretics. To avoid the capture of intermittent use of corticosteroids for acute infections, we found requiring a minimum of 45 days cumulative exposure was reasonable to determine chronic use. What is Known: • Guidelines from the American Academy of Pediatrics recommend palivizumab immunoprophylaxis for children with CLD in their second year of life if they continue to need treatment within 6 months before the RSV season. • The utilization patterns of treatment (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) are not well understood. A definition of chronic corticosteroid therapy in this setting is not available. What is New: • Among infants and children with CLD of prematurity, 35.2% received one or more medical treatments for CLD any time within 200 days before entering the second RSV season: 8.6%, 3.2%, and 29.7% received oxygen, diuretics, and corticosteroids, respectively. Utilization decreased as infants' age increased with corticosteroids surpassing oxygen and diuretics. • A minimum of 45 days cumulative corticosteroid use within the past 90 days would accurately capture chronic use to fulfill criteria for immunoprophylaxis while limiting the inclusion of intermittent use of corticosteroids for acute infections.

Incidence of mother-to-child transmission of hepatitis B in relation to maternal peripartum antiviral prophylaxis: A systematic review and meta-analysis.

INTRODUCTION: Mother-to-child transmission (MTCT) of the hepatitis B virus (HBV) is a serious public health challenge. Estimating HBV MTCT incidence by region under different prophylaxis regimens is critical to understanding the regional disease burden and prioritizing interventions. This study aimed to calculate HBV MTCT incidence under different prophylaxis regimens globally and regionally and identify the HBV DNA threshold for maternal peripartum antiviral prophylaxis. MATERIAL AND METHODS: This review was registered in advance in PROSPERO (CRD 42019120567). We searched PubMed, Embase, China National Knowledge Infrastructure, ClinicalTrials.gov, and Cochrane Library databases for studies on MTCT in pregnant women with chronic HBV infection from their inception until June 13, 2022. MTCT was defined as hepatitis B surface antigen (HBsAg) or HBV DNA seropositivity in infants aged 6-12 months. We calculated the pooled HBV MTCT incidence using the DerSimonian-Laird random-effects model. RESULTS: Among 300 studies, 3402 of 63 293 infants had HBV due to MTCT. Without prophylaxis regimens, the pooled HBV MTCT incidence was 31.3%, ranging from 0.0% (95% confidence interval [CI] 0.0%-6.0%; European Region) to 46.1% (95% CI 29.7%-63.0%; Western Pacific Region). Following the introduction of the hepatitis B vaccine, the HBV MTCT incidence decreased from 82.9% to 15.9% in HBeAg-positive women and from 10.3% to 2.3% in HBeAg-negative women. Maternal peripartum antiviral treatment alongside infant immunoprophylaxis further decreased MTCT incidence to 0.3% (95% CI 0.1%-0.5%). Despite infant immunoprophylaxis, the incidences of MTCT at maternal HBV DNA levels of <2.30, 2.00-3.29, 3.00-4.29, 4.00-5.29, 5.00-6.29, 6.00-7.29 and ≥7.00 log10  IU/ml were 0.0% (95% CI 0.0%-0.0%), 0.0% (95% CI 0.0%-0.0%), 0.0% (95% CI 0.0%-0.5%), 0.6% (95% CI 0.0%-2.6%), 1.0% (95% CI 0.0%-3.1%), 4.3% (95% CI 1.8%-7.5%), and 9.6% (95% CI 7.0%-12.5%), respectively. CONCLUSIONS: HBV MTCT incidence varies across regions. The Western Pacific Region bears the heaviest burden. Peripartum antiviral prophylaxis plus infant immunoprophylaxis is promising for interrupting HBV MTCT. Regarding the HBV DNA threshold for peripartum antiviral prophylaxis, maternal HBV DNA of 4.00 log10  IU/ml or greater seems justified.

Use of mathematical modelling to assess respiratory syncytial virus epidemiology and interventions: a literature review.

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection worldwide, resulting in approximately sixty thousand annual hospitalizations of< 5-year-olds in the United States alone and three million annual hospitalizations globally. The development of over 40 vaccines and immunoprophylactic interventions targeting RSV has the potential to significantly reduce the disease burden from RSV infection in the near future. In the context of RSV, a highly contagious pathogen, dynamic transmission models (DTMs) are valuable tools in the evaluation and comparison of the effectiveness of different interventions. This review, the first of its kind for RSV DTMs, provides a valuable foundation for future modelling efforts and highlights important gaps in our understanding of RSV epidemics. Specifically, we have searched the literature using Web of Science, Scopus, Embase, and PubMed to identify all published manuscripts reporting the development of DTMs focused on the population transmission of RSV. We reviewed the resulting studies and summarized the structure, parameterization, and results of the models developed therein. We anticipate that future RSV DTMs, combined with cost-effectiveness evaluations, will play a significant role in shaping decision making in the development and implementation of intervention programs.

Application of hepatitis B immunoglobulin in prevention of mother-to-child transmission of chronic hepatitis B in HBsAg- and HBeAg-positive mother.

The aim of our study was to compare the efficacy of two dosages of hepatitis B immunoglobulin (HBIG) combined with HBV vaccine (HBVac) to prevent mother-to-child transmission (MTCT) of hepatitis B in HBsAg- and HBeAg-positive mother. We enrolled 331 mother-infant pairs with HBsAg- and HBeAg-positive maternal state from the Women's Hospital School of Medicine of Zhejiang University. Newborns were randomly distributed into two groups according to the dosages of HBIG injection: 100 IU and 200 IU. Newborns from both groups were injected with HBVac in the same doses. We compared the immune outcomes between the two groups and explore the influencing factors of immune outcomes through regression analysis. There was no statistically significant relationship between HBsAg serological transmission of newborns and dosages of HBIG in HBsAg- and HBeAg-positive mother (p > .05). The Logistic regression showed that high DNA load is a risk factor for passive-active immunoprophylaxis failure for both 100 IU and 200 IU group, but higher-dosage HBIG is not necessary for higher-viral-load pregnant women with HBsAg- and HBeAg-positive. In conclusion, combined application of HBVac and a single dose of 100 IU HBIG can achieve the ideal MTCT interruption results for HBsAg- and HBeAg-positive pregnant women.IMPACT STATEMENTWhat is already known on this subject? Passive-active immunoprophylaxis is proved to be effective in preventing mother-to-child transmission of hepatitis B. Hepatitis B vaccine combined with 100 IU or 200 IU immunoglobulin is mostly recommended in China.What do the results of this study add? At present, there is still a lack scientific basis for improving existing strategies and measures to prevent mother-to-child transmission of hepatitis B in China.What are the implications of these findings for clinical practice and/or further research? 100 IU and 200 IU immunoglobulin show equivalent blocking effect, and combined use of hepatitis B vaccine and 100 IU immunoglobulin is more cost-effective.

Effectiveness of Palivizumab Against Respiratory Syncytial Virus Hospitalization Among Preterm Infants in a Setting With Year-Round Circulation.

BACKGROUND: The year-round respiratory syncytial virus (RSV) circulation in tropical regions leads to different transmission patterns and burden of disease among infants born very preterm. METHODS: We conducted a retrospective cohort study to estimate the effectiveness of palivizumab in preventing RSV hospitalization at 6 and 12 months after discharge, among infants born at <32 weeks' gestation in our tropical setting. RESULTS: A total of 109 infants (26.3%) received palivizumab at discharge, of 415 who were eligible. All patients received ≥4 doses, with 105 infants (96.3%) completing 5 doses. Within 1 year after discharge, there were 35 RSV-associated admissions (3 [2.8%] in the palivizumab vs 32 [10.5%] in the nonpalivizumab group; P = .02). After adjustment for confounders, the effectiveness of palivizumab against RSV hospitalization was estimated to be 90% (95% confidence interval, 10%-99%) up to 6 months after discharge. The median time to RSV hospitalization was shorter in the nonpalivizumab than in the palivizumab group (median [range], 155 [15-358] vs 287 [145-359] days, respectively; P = .11). Five infants (14.3%), all from the nonpalivizumab group, required admission to the intensive care unit. CONCLUSIONS: In our setting with year-round RSV circulation, palivizumab prophylaxis was effective in reducing RSV hospitalization among high-risk preterm infants of <32 weeks' gestation within the initial 6 months after discharge.

The dynamic changes of HBV quasispecies diversity in infancy after immunoprophylaxis failure: a prospective cohort study.

BACKGROUND: Previous works have observed that younger infants with chronic hepatitis B virus (HBV) infection are more responsive to antiviral treatment. However, the underlying mechanism remains unclear. In this study, the dynamic changes of HBV quasispecies in infants with immunoprophylaxis failure were investigated to provide virological explanations for clinical management on infantile antiviral therapy. METHODS: Thirteen 7-month-old infants with immunoprophylaxis failure and their mothers were enrolled from a prospective cohort, and 8 of them were followed up to 3 years old. The sequences of HBV quasispecies were analyzed by the full-length genome clone-based sequencing, and compared among mothers and their infants at different ages. RESULTS: The results revealed that the complexity, mutation frequency and genetic distance of HBV quasispecies decreased significantly at full-length, partial open reading frames and regulatory regions of HBV genome at nucleotide level in 7-month-old infants comparing with their mothers, whereas increased significantly to near the maternal level when infants grew up to 3 years old. Furthermore, similar changes were also found in Core, PreS2, RT and P regions of HBV genome at amino acid level, especially for potential NAs-resistant mutants in RT region and immune-escape mutants in Core and PreS2 regions. CONCLUSIONS: This study uncovered the evolution of HBV quasispecies in infancy after mother-to-child transmission, which may provide the virological evidence for explaning that younger children are more responsive to antiviral therapy.

Immunogenicity in Oreochromis niloticus vaccinated with sonicated antigens against streptococcosis.

Streptococcosis causes great economic losses in intensive culture of tilapia. Vaccination is the most effective and safest way to tackle infectious diseases. Thus, this study sought the more effective and safer antigenic fraction after sonication of Streptococcus agalactiae to elaborate a vaccine against streptococcosis in Nile tilapia. For this, twenty-one days after vaccination with different fractions (soluble and insoluble) of S. agalactiae, the fish were challenged with the homologous strain (LD50). Then, samples were taken at zero, 14, 28, 60 and 90 days post-vaccination (DPV, n = 7). Blood and organs (cranial kidney, spleen and liver) were collected from vaccinated and unvaccinated fish. Finally, insoluble fraction vaccine presented the best effect, resulting in a 100% relative percent of survival (RPS) and without clinical manifestations. In view of the results, it was to evaluate the role of the insoluble fraction of the antigen in the protective immunity against streptococcosis. The results indicate that the spleen might be the main organ in the vaccine response in Nile tilapia due to the great morphological and immunological differences in vaccinated fish, evidenced by the greater of melanomacrophage centers (MMC) and IgM + lymphocytes in relation to the non-vaccinated fish. At 60 DPV, it was observed the peak of the protective immunity related to the maximum concentration of proteins, circulating leukocytes, antibody titers in the serum and tissue changes with greater expression of IgM + and MMC number in the spleen and kidney of Oreochromis niloticus. Vaccination with insoluble fraction of S. agalactiae was safe and provided effective protection against streptococcosis with maximum protective response at 60 DPV.

Vaccines for caseous lymphadenitis: up-to-date and forward-looking strategies.

Caseous lymphadenitis (CLA) is an infectious chronic disease responsible for economic losses in sheep and goat breeding worldwide. CLA has no effective treatment, evidencing the vaccination schedule as the best control strategy. Although some commercial vaccines have been available, none of them provides total protection, which is sometimes insufficient and does not reach the same efficiency when compared in sheep and goats. They also have questionable safety levels and side effects. In light of this, several experimental vaccines are in development in order to improve safety, reproducibility, and protective immune response against the etiologic agent of CLA, Corynebacterium pseudotuberculosis. In this review, we discussed aspects as antigen, adjuvant, routes of administration, protection level, and animal models used in CLA vaccine development, as well the challenges and future perspectives. KEY POINTS: Caseous lymphadenitis (CLA) does not have an appropriate commercial vaccine. Different experimental vaccines are in development aiming to protect against Corynebacterium pseudotuberculosis. An ideal vaccine for CLA is necessary for the disease control.

Antibody gene transfer with adeno-associated viral vectors as a method for HIV prevention.

Broadly neutralizing antibodies (bNAbs) against human immunodeficiency virus (HIV) show great promise in HIV prevention as they are capable of potently neutralizing a considerable breadth of genetically diverse strains. Passive transfer of monoclonal bNAb proteins can confer protection in animal models of HIV infection at modest concentrations, inspiring efforts to develop an HIV vaccine capable of eliciting bNAb responses. However, these antibodies demonstrate high degrees of somatic mutation and other unique characteristics that may hinder the ability of conventional approaches to consistently and effectively produce bNAb analogs. As an alternative strategy, we and others have proposed vector-mediated gene transfer to generate long-term, systemic production of bNAbs in the absence of immunization. Herein, we review the use of adeno-associated virus (AAV) vectors for delivery of HIV bNAbs and antibody-like proteins and summarize both the advantages and disadvantages of this strategy as a method for HIV prevention.