Inhibition of Biofilm Formation in Cutibacterium acnes, Staphylococcus aureus, and Candida albicans by the Phytopigment Shikonin.

Skin microbiota, such as acne-related Cutibacterium acnes, Staphylococcus aureus, and fungal Candida albicans, can form polymicrobial biofilms with greater antimicrobial tolerance to traditional antimicrobial agents and host immune systems. In this study, the phytopigment shikonin was investigated against single-species and multispecies biofilms under aerobic and anaerobic conditions. Minimum inhibitory concentrations of shikonin were 10 µg/mL against C. acnes, S. aureus, and C. albicans, and at 1-5 µg/mL, shikonin efficiently inhibited single biofilm formation and multispecies biofilm development by these three microbes. Shikonin increased porphyrin production in C. acnes, inhibited cell aggregation and hyphal formation by C. albicans, decreased lipase production, and increased hydrophilicity in S. aureus. In addition, shikonin at 5 or 10 µg/mL repressed the transcription of various biofilm-related genes and virulence-related genes in C. acnes and downregulated the gene expression levels of the quorum-sensing agrA and RNAIII, α-hemolysin hla, and nuclease nuc1 in S. aureus, supporting biofilm inhibition. In addition, shikonin prevented multispecies biofilm development on porcine skin, and the antimicrobial efficacy of shikonin was recapitulated in a mouse infection model, in which it promoted skin regeneration. The study shows that shikonin inhibits multispecies biofilm development by acne-related skin microbes and might be useful for controlling bacterial infections.

Exploitation of a novel adjuvant for polymyxin B against multidrug-resistant Acinetobacter baumannii.

BACKGROUND: Although polymyxin has been used as a last-resort antibiotic against resistant bacteria, its use is restricted due to nephrotoxicity and neurotoxicity. While the present antibiotic resistance issue compels clinicians to reconsider polymyxin use in severe illness cases, polymyxin-resistant microorganisms exert an effect. OBJECTIVES: To address the issue of antibiotic resistance, the cycle of developing new antibiotics to counteract emerging resistance must be discontinued. Here we tried to develop novel therapies that do not rely on direct antimicrobial activity and thus do not promote antibiotic resistance. METHODS: By a high-throughout screening system based on bacterial respiration, chemical compounds accelerating the antimicrobial effects of polymyxin B were screened. In vitro and in vivo tests were performed to validate adjuvanticity. In addition, membrane depolarization and total transcriptome analysis were used to determine molecular mechanisms. RESULTS: PA108, a newly discovered chemical compound, was used to eradicate polymyxin-resistant A. baumannii and three other species in the presence of polymyxin B at concentrations less than the MIC. Since this molecule lacks self-bactericidal action, we hypothesized that PA108 acts as an antibiotic adjuvant, enhancing the antimicrobial activity of polymyxin B against resistant bacteria. At working concentrations, no toxicity was observed in cell lines or mice, although co-treatment with PA108 and polymyxin B increased survival of infected mouse and decreased bacterial loads in organs. CONCLUSIONS: Boosting antibiotic efficiency through the use of antibiotic adjuvants holds significant promise for tackling the rise in bacterial antibiotic resistance.

Subacute oral toxicity and bacterial mutagenicity of a mixture of Puerariae radix and Hizikia fusiforme extracts.

The study aims to identify the safety profile of a mixed extract (KGC-02-PS) from two traditional medicinal herbs, Puerariae radix and Hizikia fusiforme. In a subacute oral toxicity study, KGC-02-PS was administered orally for 28 days by gavage to Sprague Dawley rats (both sexes) at a daily dose of 0, 500, 1000, and 2000 mg/kg body weight. Bodyweight, food consumption, and clinical signs were monitored during the experimental period. After administering the final dose, this study conducted hematology, serum biochemistry, and pathological evaluations. In addition, the study performed a bacterial reverse mutation test with varying concentrations of KGC-02-PS (312.5 µg - 5,000 µg/plate) following OECD guideline No. 471, before testing five bacterial strains (Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2) in the presence or absence of metabolic activation. The preclinical evaluation of KGC-02-PS's subacute oral toxicity yielded no associated toxicological effects or any changes in clinical signs, body weight, and food consumption. Moreover, examining KGC-02-PS's hematological and serum biochemical characteristics and pathology yielded no toxicological changes in terms of organ weight measurements and gross or histopathological findings. KGC-02-PS neither increased the number of revertant colonies in all bacterial strains used in the bacterial reverse mutation test, nor did it induce genotoxicity related to bacterial reverse mutations under the study's conditions. Also, KGC-02-PS's no-observed-adverse-effect level was greater than 2000 mg/kg.

Comparison of porcine circovirus type 2 (PCV2)-associated lesions produced by co-infection between two genotypes of PCV2 and two genotypes of porcine reproductive and respiratory syndrome virus.

The objective of this study was to compare the virulence and pathogenicity of a combination of concurrent infections of two genotypes of porcine circovirus type 2 (PCV2) and two genotypes of porcine reproductive and respiratory syndrome virus (PRRSV) in terms of PCV2 viraemia, and PCV2-associated lesions and antigens in co-infected pigs. Pigs with PCV2a (or 2b)/type 1 (or type 2) PRRSV had significantly (P<0.05) higher mean clinical respiratory scores and lower average daily weight gain compared with pigs with PCV2a (or 2b). Co-infection induced significantly lower levels of anti-PCV2 and anti-PRRSV IgG antibodies than infection with one genotype alone, regardless of the genotype of the two viruses. Pigs with PCV2a (or 2b)/type 2 PRRSV had significantly (P<0.05) higher levels of PCV2 viraemia, more severe PCV2-associated lesions, and more PCV2 DNA within the lesions compared with pigs with PCV2a (or 2b)/type 1 PRRSV. However, there was no significant difference in these parameters in pigs with PCV2a/type 2 PRRSV or PCV2b/type 2 PRRSV. The results of this study demonstrate significant differences in the virulence and pathogenicity of type 1 and type 2 PRRSV but no significant differences in the virulence and pathogenicity of PCV2a and PCV2b with respect to the production of PCV2-associated lesions.

Vaccination of sows against type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) before artificial insemination protects against type 2 PRRSV challenge but does not protect against type 1 PRRSV challenge in late gestation.

The objective of the present study was to determine the effects of the commercially available type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)-based modified live vaccine against type 1 and type 2 PRRSV challenge in pregnant sows. Half of the sows in the study were vaccinated with a type 2 PRRSV-based vaccine 4 weeks prior to artificial insemination while the other half remained non-vaccinated. Sows were then challenged intranasally with type 1 or type 2 PRRSV at 93 days of gestation. The sows which received the type 2 PRRSV-based vaccine followed by type 2 PRRSV challenge had significantly higher neutralizing antibody titers against type 2 PRRSV than they did against type 1 PRRSV. These same sows had higher frequencies of IFN-γ-secreting cells when stimulated with type 2 PRRSV compared to those stimulated with type 1 PRRSV. Subsequent virological evaluation demonstrated that the type 2 PRRSV-based vaccine reduced the type 2 PRRSV load but not the type 1 PRRSV load present in the blood of the sows. Additionally, vaccination of pregnant sows with the type 2 PRRSV-based vaccine effectively reduced the level of type 2 PRRSV nucleic acids observed in fetal tissues from type 2 PRRSV-challenged sows but did not reduce the level of type 1 PRRSV nucleic acid observed in fetal tissues from type 1 PRRSV-challenged sows. This study demonstrates that the vaccination of pregnant sows with the type 2 PRRSV-based vaccine protects against type 2 PRRSV challenge but does not protect against type 1 PRRSV challenge.

Effect of porcine circovirus type 2 (PCV2) vaccination on PCV2-viremic piglets after experimental PCV2 challenge.

The objective of this study was to evaluate the effect of porcine circovirus type 2 (PCV2) vaccines on PCV2-viremic and -seropositive piglets born from naturally PCV2-infected sows against postnatal PCV2 challenge. The experimental design was aimed at mimicking commercial swine rearing conditions to evaluate the response of the PCV2 vaccine on PCV2-viremic and -seropositive piglets after experimental PCV2 challenge. PCV2a (or 2b)-viremic piglets received a PCV2 vaccine at 21 days of age followed by a PCV2b (or 2a) challenge at 49 days of age (28 days post vaccination). The PCV2 vaccines elicited a high level of humoral (as measured by immunoperoxidase monolayer assay and neutralizing antibody titers) and cellular (as measured by the frequency of PCV2-specific interferon-γ-secreting cells) immune response in the PCV2-viremic piglets after vaccination even in the presence of maternally derived antibodies (MDA). The initial infection of PCV2 in the pigs was not affected by PCV2 vaccination, however the challenging PCV2 was reduced by PCV2 vaccination on PCV2-viremic pigs. The results from this study demonstrate that the PCV2 vaccine used in this study is effective at reducing PCV2 viremia and lymphoid PCV2 DNA, even for PCV2-viremic pigs with passively acquired MDA at the time of vaccination.

Genetic and antigenic characterization of a newly emerging porcine circovirus type 2b mutant first isolated in cases of vaccine failure in Korea.

This study describes the genetic and antigenic characterization of a newly emerging porcine circovirus type 2b (PCV2b) mutant first isolated in cases of vaccine failure in Korea. The full genome of the PCV2b isolates (SNUVR130689 and SNUVR140004) is 1,767 base pairs (bp) in length. The size of ORF1 is 945 bp, encoding a protein of 314 amino acids (aa), and the size of ORF2 is 705 bp, encoding a protein of 234 aa, which is 1 aa longer than that of the common PCV2 (233 aa). Korean PCV2b mutant strains had higher levels of nucleotide sequence identity to other PCV2b mutant strains (99.7-99.8 %) than to reference PCV2a (94.5-95.0 %) and PCV2b (95.5-96.1 %) strains. There was no difference in antigenic reactivity among PCV2a, PCV2b and PCV2b mutant strains to the polyclonal and monoclonal PCV2a antibodies. PCV2b mutant strains have distinct genetic characteristics but similar antigenic reactivity when compared to common PCV2a and 2b strains.

3-O-Substituted Quercetin: an Antibiotic-Potentiating Agent against Multidrug-Resistant Gram-Negative Enterobacteriaceae through Simultaneous Inhibition of Efflux Pump and Broad-Spectrum Carbapenemases.

The discovery of safe and efficient inhibitors against efflux pumps as well as metallo-ß-lactamases (MBL) is one of the main challenges in the development of multidrug-resistant (MDR) reversal agents which can be utilized in the treatment of carbapenem-resistant Gram-negative bacteria. In this study, we have identified that introduction of an ethylene-linked sterically demanding group at the 3-OH position of the previously reported MDR reversal agent di-F-Q endows the resulting compounds with hereto unknown multitarget inhibitory activity against both efflux pumps and broad-spectrum ß-lactamases including difficult-to-inhibit MBLs. A molecular docking study of the multitarget inhibitors against efflux pump, as well as various classes of ß-lactamases, revealed that the 3-O-alkyl substituents occupy the novel binding sites in efflux pumps as well as carbapenemases. Not surprisingly, the multitarget inhibitors rescued the antibiotic activity of a carbapenem antibiotic, meropenem (MEM), in NDM-1 (New Delhi Metallo-ß-lactamase-1)-producing carbapenem-resistant Enterobacteriaceae (CRE), and they reduced MICs of MEM more than four-fold (synergistic effect) in 8-9 out of 14 clinical strains. The antibiotic-potentiating activity of the multitarget inhibitors was also demonstrated in CRE-infected mouse model. Taken together, these results suggest that combining inhibitory activity against two critical targets in MDR Gram-negative bacteria, efflux pumps, and ß-lactamases, in one molecule is possible, and the multitarget inhibitors may provide new avenues for the discovery of safe and efficient MDR reversal agents.

Facemask acne attenuation through modulation of indirect microbiome interactions.

During the COVID-19 pandemic, facemasks played a pivotal role in preventing person-person droplet transmission of viral particles. However, prolonged facemask wearing causes skin irritations colloquially referred to as 'maskne' (mask + acne), which manifests as acne and contact dermatitis and is mostly caused by pathogenic skin microbes. Previous studies revealed that the putative causal microbes were anaerobic bacteria, but the pathogenesis of facemask-associated skin conditions remains poorly defined. We therefore characterized the role of the facemask-associated skin microbiota in the development of maskne using culture-dependent and -independent methodologies. Metagenomic analysis revealed that the majority of the facemask microbiota were anaerobic bacteria that originated from the skin rather than saliva. Previous work demonstrated direct interaction between pathogenic bacteria and antagonistic strains in the microbiome. We expanded this analysis to include indirect interaction between pathogenic bacteria and other indigenous bacteria classified as either 'pathogen helper (PH)' or 'pathogen inhibitor (PIn)' strains. In vitro screening of bacteria isolated from facemasks identified both strains that antagonized and promoted pathogen growth. These data were validated using a mouse skin infection model, where we observed attenuation of symptoms following pathogen infection. Moreover, the inhibitor of pathogen helper (IPH) strain, which did not directly attenuate pathogen growth in vitro and in vivo, functioned to suppress symptom development and pathogen growth indirectly through PH inhibitory antibacterial products such as phenyl lactic acid. Taken together, our study is the first to define a mechanism by which indirect microbiota interactions under facemasks can control symptoms of maskne by suppressing a skin pathogen.

DECIPHERING GUT MICROBIOTA IN PATIENTS WITH SEVERE SEPSIS AND SEPTIC SHOCK.

ABSTRACT: Introduction: Gut microbiota dysbiosis is associated with susceptibility to sepsis and poor outcomes. However, changes to the intestinal microbiota during sepsis and their value as biomarkers are unclear. In this study, we compared the intestinal microbiota of patients with sepsis and healthy controls. Methods: Stool was collected from patients with sepsis (subdivided according to mortality) and controls. Microbiome diversity and composition were analyzed by 16S rRNA gene pyrosequencing. The α-diversity of the intestinal microbiome was determined using operational taxonomic unit counts and the Chao1, Shannon, and ACE indices. Adjusted Cox regression analyses assessed 6-month mortality risk factors. Results: Fifty-nine patients (14 in-hospital deaths) and 29 healthy controls were enrolled. Operational taxonomic unit counts and Chao1 and ACE indices were lower in the nonsurvivor than in the other groups. The controls showed a higher Shannon and lower Simpson index than did the sepsis group. The genus Blautia was more abundant in controls than in the sepsis group, and Faecalibacterium less abundant in the nonsurvivor than in the other groups. Regression analysis associated low Shannon index with 6-month mortality. Conclusions: Survivors of sepsis, nonsurvivors, and healthy controls have different gut microbiomes, and a low Shannon index is a risk factor for 6-month mortality.

Comparative pathogenesis of type 1 (European genotype) and type 2 (North American genotype) porcine reproductive and respiratory syndrome virus in infected boar.

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) now has two main genotypes, genotype 1 (European) and genotype 2 (North American). There is a lack of data on the comparison of pathogenicity of the two genotypes in boars. The objectives of the present study were to evaluate the amount of PRRSV present in semen over time and compare the viral distribution and microscopic lesions of type 1 and type 2 PRRSV-infected boars. METHODS: Twenty-four 8-month-old PRRSV-naïve Duroc boars were randomly allocated to 3 treatment groups. The boars in groups 1 (n = 9) and 2 (n = 9) were intranasally inoculated with type 1 or type 2 PRRSV, respectively. The boars in groups 1 (n = 6) served as negative controls. Semen and blood samples were collected up to 35 days post-inoculation (dpi), and necropsies were performed on 14, 21, and 35 dpi. RESULTS: There were no significant differences in the genomic copy number of PRRSV, microscopic testicular lesion score, number of PRRSV-positive germ cells, or number of apoptotic cells between the type 1 and type 2 PRRSV-infected boars throughout the experiment. Histopathological changes were manifested by the desquamation of spermatocytes and the presence of multinucleated giant cells in seminiferous tubules of both type 1 and type 2 PRRSV-infected boars. The distribution of PRRSV-positive cells was focal; the virus was found in single germ cells or small clusters of germ cells, localized to the spermatogonia, spermatocytes, spermatids, and non-sperm cells in type 1 and type 2 PRRSV-infected boars. CONCLUSIONS: The results of this study demonstrated that two genotypes of PRRSV do not have significantly different virulence toward the male reproductive system of pigs.

Differential toxic responses between pristine and functionalized multiwall nanotubes involve induction of autophagy accumulation in murine lung.

Carbon nanotubes (CNT) are becoming commonly used in industrial applications. However, the toxicity associated with this material remains to be established. The aim of this study was to investigate the potential toxic mechanisms associated with multiwall carbon nanotubes (MWCNT) in normal mouse lung. A total of 100 µg of two types of MWCNT, namely, pristine MWCNT (PMWCNT) and acid-treated-MWCNT (TMWCNT), was administered to male C57BL/6 mice via intratracheal (IT) instillation for a period of 6 mo. Our results indicated that PMWCNT induced pulmonary autophagy accumulation and resulted in more potent tumorigenic effects compared to TMWCNT. Accordingly, MWCNT may exert differential toxicity attributed to various physicochemical properties. Data emphasize the need for careful regulation of production and use of CNT.

A Postmortem Case Study-An Analysis of microRNA Patterns in a Korean Native Male Calf (Bos taurus coreanae) That Died of Fat Necrosis.

Korean native cattle are highly valued for their rich marbling and flavor. Nonetheless, endeavors to enhance marbling levels can result in obesity, a prevalent contributor to fat necrosis. Fat necrosis is characterized by the formation of necrotic fat masses in the abdominal cavity, which physically puts pressure on affected organs, causing physical torsion or obstruction, resulting in death and consequent economic loss. Pancreatic injuries or diabetes mellitus were reported as factors of fat necrosis in humans; however, the pathogenesis in animals has not been established. In this study, we identified fat necrosis in a 6-month-old Korean native cow and investigated its potential underlying causes. Serum samples were utilized for a microarray analysis of bovine miRNA. Comparative examination of miRNA expression levels between cattle afflicted with fat necrosis and healthy cattle unveiled notable variances in 24 miRNAs, such as bta-miR-26a, bta-miR-29a, bta-miR-30a-5p and bta-miR-181a. Upon conducting miRNA-mediated KEGG pathway analysis, several pathways including the prolactin signal pathway, insulin resistance, autophagy, the insulin-signaling pathway and the FoxO-signaling pathway were found to be significantly enriched in the calf affected by fat necrosis. As a result, this study potentially indicates a potential connection between fat necrosis and diabetes in Korean native cattle.

Prebiotic potential of green banana flour: impact on gut microbiota modulation and microbial metabolic activity in a murine model.

Introduction: Green banana flour can be used as a prebiotic due to its ability to promote gut health and provide several health benefits. In this study, we investigated whether feeding mice green banana flour at different doses would alter intestinal microbiota composition. Methods: We fed C57BL/6N mice either a Low-dose (500 mg/kg/day) or High-dose (2000 mg/kg/day) of green banana flour daily for 3 weeks, and fecal samples were collected on days 0, 14, and 21 for microbiota analysis. Results: Our results showed that the composition of intestinal microbiota was significantly altered by day 21, regardless of the dose. Notably, the consumption of green banana flour increased the presence of beneficial bacteria, including Coriobacteriaceae_UCG-002, Turicibacter, Parasutterella, Gastranaerophilales_ge, and RF39_ge. These changes in the intestinal microorganisms were accompanied by increased biological processes such as amino acid biosynthesis and secondary metabolite biosynthesis. Conversely, the consumption of green banana flour resulted in a decrease in biological processes related to carbohydrate degradation, glycerol degradation, and similar functions. Discussion: These results emphasize the potential of green banana flour as a prebiotic that can benefit the gut microbiome.

Protective Effect of Novel Lactobacillus plantarum KC3 Isolated from Fermented Kimchi on Gut and Respiratory Disorders.

Probiotics have been shown to possess anti-inflammatory effects in the gut by directly reducing the production of pro-inflammatory cytokines and by secreting anti-inflammatory molecules. However, their systemic anti-inflammatory effects have not been thoroughly investigated. In this study, we aimed to develop probiotics that have efficacy in both intestinal and lung inflammation. Lactobacillus plantarum KC3 (KC3), which was isolated from kimchi, was selected as a pre-candidate based on its inhibitory effects on the production of pro-inflammatory cytokines in vitro. To further validate the effectiveness of KC3, we used ear edema, DSS-induced colitis, and ambient particulate-matter-induced lung inflammation models. First, KC3 exhibited direct anti-inflammatory effects on intestinal cells with the inhibition of IL-1ß and TNF-α production. Additionally, KC3 treatment alleviated ear edema and DSS-induced colic inflammation, improving colon length and increasing the number of regulatory T cells. Beyond its local intestinal anti-inflammatory activity, KC3 inhibited pro-inflammatory cytokines in the bronchoalveolar fluid and prevented neutrophil infiltration in the lungs. These results suggest that KC3 could be a potential functional ingredient with respiratory protective effects against air-pollutant-derived inflammation, as well as for the treatment of local gut disorders.

A Plant-Derived Maternal Vaccine against Porcine Epidemic Diarrhea Protects Piglets through Maternally Derived Immunity.

Newborn piglets are susceptible to a highly contagious enteritis caused by the porcine epidemic diarrhea virus (PEDV), associated with high levels of mortality worldwide. There is pressing need for a rapid, safe, and cost-effective vaccine to safeguard pigs from getting infected by PEDV. PEDV belongs to the coronavirus family and is characterized by high levels of mutability. The primary goal of a PEDV vaccine is to provide immunity to newborn piglets through vaccination of sows. Plant-based vaccines are becoming more popular because they have low manufacturing costs, are easily scalable, have high thermostability, and a long shelf life. This is in contrast to conventional vaccines which include inactivated, live, and/or recombinant types that can be expensive and have limited ability to respond to rapidly mutating viruses. The binding of the virus to host cell receptors is primarily facilitated by the N-terminal subunit of the viral spike protein (S1), which also contains several epitopes that are recognized by virus-neutralizing antibodies. As a result, we generated a recombinant S1 protein using a plant-based vaccine platform. We found that the recombinant protein was highly glycosylated, comparable to the native viral antigen. Vaccination of pregnant sows at four and two weeks before farrowing led to the development of humoral immunity specific to S1 in the suckling piglets. In addition, we noted significant viral neutralization titers in both vaccinated sows and piglets. When challenged with PEDV, piglets born from vaccinated sows displayed less severe clinical symptoms and significantly lower mortality rates compared to piglets born from non-vaccinated sows.

Second Skin as Self-Protection Against γ-Hydroxybutyrate.

γ-Hydroxybutyrate (GHB), a date-rape drug, causes certain symptoms, such as amnesia, confusion, ataxia, and unconsciousness, when dissolved in beverages and consumed by a victim. Commonly, assailants use GHB in secret for the crime of drug-facilitated sexual assault because it is tasteless, odorless, and colorless when dissolved in beverages. Generally, GHB detection methods are difficult to use promptly and secretly in situ and in real life because of the necessary detection equipment and low selectivity. To overcome this problem, we have developed a fast, simple, and easy-to-use second skin platform as a confidential self-protection platform that can detect GHB in situ or in real life without equipment. The second skin platform for naked-eye detection of GHB is fabricated with poly(vinyl alcohol) (PVA), polyurethane (PU), and polyacrylonitrile (PAN) included in the chemical receptor 2-(3-bromo-4-hydroxystyryl)-3-ethylbenzothiazol-3-ium iodide (BHEI). PAN conjugated with BHEI nanofibers (PB NFs) has various characteristics, such as ease of use, high sensitivity, and fast color change. PB NFs rapidly detected GHB at 0.01 mg/mL. Furthermore, the second-skin platform attached to the fingertip and wrist detected both 1 and 0.1 mg/mL GHB in solution within 50 s. The color changes caused by the interaction of GHB and the second skin platform cannot be stopped due to strong chemical reactions. In addition, a second skin platform can be secretly utilized in real life because it can recognize fingerprints and object temperatures. Therefore, the second skin platform can be used to aid daily life and prevent drug-facilitated sexual assault crime when attached to the skin because it can be exposed anytime and anywhere.

Protective effect of the maternally derived porcine circovirus type 2 (PCV2)-specific cellular immune response in piglets by dam vaccination against PCV2 challenge.

The objective of the present study was to evaluate (i) the passive transfer of maternally derived functional porcine circovirus type 2 (PCV2)-specific lymphocytes of seronegative sows immunized with the PCV2 vaccine to newborn piglets and (ii) the functional role of the maternally derived PCV2-specific cellular immune response in protecting newborn piglets from challenge with PCV2. After ingesting colostrums, piglets from vaccinated sows (PT01 and PT02) have significantly higher numbers of PCV2-specific gamma interferon-secreting cells, an increased PCV2-specific delayed type hypersensitivity response, and a stronger proliferative response of peripheral blood mononuclear cells compared with piglets from non-vaccinated seronegative sows (PT03 and PT04). In the PCV2 challenge study, the number of serum genomic PCV2 copies was significantly less in piglets from vaccinated sows (PT02) compared with piglets from non-vaccinated sows (PT04) at 7-28 days post-inoculation (P<0.05 and P<0.001). The histopathological lesions and immunohistochemical scores were significantly lower in piglets of vaccinated sows compared with those of non-vaccinated sows. To our knowledge, this is the first report of transferring a maternally derived PCV2-specific cellular immune response from vaccinated dams to their offspring. Maternally derived adaptive cellular immune responses play a critical role in protecting newborn piglets challenged with PCV2 at 3 weeks of age.

Reduction of porcine circovirus type 2 (PCV2) viremia by a reformulated inactivated chimeric PCV1-2 vaccine-induced humoral and cellular immunity after experimental PCV2 challenge.

BACKGROUND: The objective of the present study was to elucidate the humoral and cellular immune response mechanisms by which a reformulated inactivated chimeric PCV1-2 vaccine reduces the PCV2 viremia. Forty PCV2 seronegative 3-week-old pigs were randomly divided into the following four groups: vaccinated challenged (T01), vaccinated non-challenged (T02), non-vaccinated challenged (T03), and non-vaccinated non-challenged (T04) animals. The pigs in groups T01 and T02 were immunized with a reformulated inactivated chimeric PCV1-2 vaccine (Fostera™ PCV; Pfizer Animal Health) administered as a 2.0 ml dose at 21 days of age. At 35 days of age (0 days post-challenge), the pigs in groups T01 and T03 were inoculated intranasally with 2 ml each of PCV2b. RESULTS: A reduction of PCV2 viremia coincided with the appearance of both PCV2-specific neutralizing antibodies (NA) and interferon-γ-secreting cells (IFN-γ-SCs) in the vaccinated animals. However, the presence of anti-PCV2 IgG antibodies did not correlate with the reduction of PCV2 viremia. Lymphocyte subset analysis indicated that the numbers of CD3+ and CD4+ cells increased in vaccinated animals but the numbers of CD4+ cells decreased transiently in non-vaccinated animals. The observation of a delayed type hypersensitivity response in only the vaccinated animals also supports a CD4+ cell-associated protective cellular immune response induced by the reformulated inactivated chimeric PCV1-2 vaccine. CONCLUSIONS: The induction of PCV2-specific NA and IFN-γ-SCs, and CD4+ cells by the reformulated inactivated chimeric PCV1-2 vaccine is the important protective immune response leading to reduction of the PCV2 viremia and control of the PCV2 infection. To our knowledge this is the first demonstration of protective humoral and cellular immunity induced by the reformulated inactivated chimeric PCV1-2 vaccine and its effect on reduction of PCV2 viremia by vaccination.

Identification of conserved regions from 230,163 SARS-CoV-2 genomes and their use in diagnostic PCR primer design.

BACKGROUND: As the rapidly evolving characteristic of SARS-CoV-2 could result in false negative diagnosis, the use of as much sequence data as possible is key to the identification of conserved viral sequences. However, multiple alignment of massive genome sequences is computationally intensive. OBJECTIVE: To extract conserved sequences from SARS-CoV-2 genomes for the design of diagnostic PCR primers using a bioinformatics approach that can handle massive genomic sequences efficiently. METHODS: A total of 230,163 full-length viral genomes were retrieved from the NCBI SARS-CoV-2 Resources and GISAID EpiCoV database. This number was reduced to 14.11% following removal of 5'-/3'-untranslated regions and sequence dereplication. Fast, reference-based, multiple sequence alignments identified conserved sequences and specific primer sets were designed against these regions using a conventional tool. Primer sets chosen among the candidates were evaluated by in silico PCR and RT-qPCR. RESULTS: Out of 17 conserved sequences (totaling 4.3 kb), two primer sets targeting the nsp2 and ORF3a genes were picked that exhibited > 99.9% in silico amplification coverage against the original dataset (230,163 genomes) when a 5% mismatch between the primers and target was allowed. In addition, the primer sets successfully detected nine SARS-CoV-2 variant RNA samples (Alpha, Beta, Gamma, Delta, Epsilon, Zeta, Eta, Iota, and Kappa) in experimental RT-qPCR validations. CONCLUSION: In addition to the RdRp, E, N, and S genes that are targeted commonly, our approach can be used to identify novel primer targets in SARS-CoV-2 and should be a priority strategy in the event of novel SARS-CoV-2 variants or other pandemic outbreaks.