Antigenic Variation Research Articles

Surveillance and characterization of avian-origin H3N2 canine influenza viruses in 2021 in China

Avian-origin H3N2 canine influenza virus (CIV) is one of the most prevalent influenza virus subtypes in dogs worldwide. Previous studies have shown that during the evolution of H3N2 CIV in dogs, its adaptability in mammals increased gradually, suggesting that dogs can serve as a potential intermediate host for cross-species transmission of the avian influenza virus. In this study, we report results from the surveillance and characterization of H3N2 CIVs isolated from animal hospitals and kennels in 2021 in China. We characterized the CIVs’ genetic and antigenic variation, receptor-binding specificity, and virulence in mice. The hemagglutinin (HA) phylogenetic result showed that these H3N2 CIVs belonged to Clade 5.1, a clade formed after 2019. Compared to the 2016–2019 strains in China, the 2021 H3N2 CIVs had similar antigenicity and receptor-binding specificity. The pathogenicity in mice was significantly reduced after infection with two 2021 strains, but the replication capacity was similar, suggesting that a virus-host balance might have been established. This report emphasizes the importance of close surveillance and monitoring of H3N2 CIVs in dogs to prevent the emergence of novel influenza viruses with public health threats.

YebC Modulates OspC and VlsE Inverse Regulation and VlsE Expression in Persistent Lyme Disease

Background & Hypothesis: Lyme disease, caused by the bacterium Borrelia burgdorferi, is the most common vector-borne infectious disease in the United States. Although easily treated with antibiotics, undiagnosed cases may develop into persistent infections with complications including Lyme carditis, neuroborreliosis, & arthritis. VlsE antigen variation is one of the major mechanisms employed by B. burgdorferi to establish persistent infection. We hypothesize that YebC modulates VlsE expression and antigen variation, enabling the shift from acute to persistent infection.
 Materials & Methods: C3H/HeN or C3H/SCID mice were infected with the B. burgdorferi strain 5A4NP1, yebC mutant, and yebC complement at a dose of 105 or 106 spirochetes. Mice were sacrificed at days 7, 30, 60, and 90 post-infection and tissue samples were subjected to RNA and DNA extraction.
 Results: YebC levels were closely associated with the upregulation of vlsE and the downregulation of ospC in vitro and in vivo. The yebC mutant displayed loss of infectivity in C3H/HeN mice, and reduced VlsE antigen variation.
 Conclusion & Impact: This data demonstrates that YebC of B burgdorferi can regulate the frequency of vlsE recombination and modulates the inverse regulation of OspC and VlsE. This new factor may serve as an avenue for developing drugs which can target vlsE recombination to combat complications of persistent Lyme disease.

A panel of hepatitis C virus glycoproteins for the characterization of antibody responses using antibodies with diverse recognition and neutralization patterns

A vaccine against Hepatitis C virus (HCV) is urgently needed to limit the spread of HCV. The large antigenic diversity of the HCV glycoprotein E1E2 makes it difficult to design a vaccine but also to fully understand the antibody response after infection or vaccination.Here we designed a panel of HCV pseudoparticles (HCVpps) that cover a wide range of genetically and antigenically diverse E1E2s. We validate our panel using neutralization and a binding antibody multiplex assay (BAMA). The panel of HCVpps includes E1E2 glycoproteins from acute and chronically infected cases in the Netherlands, as well as E1E2 glycoproteins from previously reported HCVs.Using eight monoclonal antibodies targeting multiple antigenic regions on E1E2, we could categorize four groups of neutralization sensitive viruses with viruses showing neutralization titers over a 100-fold range. One HCVpp (AMS0230) was extremely neutralization resistant and only neutralized by AR4-targeting antibodies. In addition, using binding antibody multiplex competition assay, we delineated mAb epitopes and their interactions. The binding and neutralization sensitivity of the HCVpps were confirmed using patient sera. At the end, eleven HCVpps with unique antibody binding and neutralization profiles were selected as the final panel for standardized HCV antibody assessments.In conclusion, this HCVpp panel can be used to evaluate antibody binding and neutralization breadth and potency as well as delineate the epitopes targeted in sera from patients or candidate vaccine trials. The HCVpp panel in combination with the established antibody competition assay present highly valuable tools for HCV vaccine development and evaluation.

Intra-serotypic antigenic diversity of dengue virus serotype 3 in Thailand during 2004-2015.

In addition to the well-known differences among the four dengue serotypes, intra-serotypic antigenic diversity has been proposed to play a role in viral evolution and epidemic fluctuation. A replacement of genotype II by genotype III of dengue virus serotype 3 (DENV3) occurred in Thailand during 2007-2014, raising questions about the role of intra-serotypic antigenic differences in this genotype shift. We characterized the antigenic difference of DENV3 of genotypes II and III in Thailand, utilizing a neutralizing antibody assay with DENV3 vaccine sera and monotypic DENV3 sera. Although there was significant antigenic diversity among the DENV3, it did not clearly associate with the genotype. Our data therefore do not support the role of intra-serotypic antigenic difference in the genotype replacement. Amino acid alignment showed that eight positions are potentially associated with diversity between distinct antigenic subgroups. Most of these amino acids were found in envelope domain II. Some positions (aa81, aa124, and aa172) were located on the surface of virus particles, probably involving the neutralization sensitivity. Notably, the strains of both genotypes II and III showed clear antigenic differences from the vaccine genotype I strain. Whether this differencewill affect vaccine efficacy requires further studies.

Transforming CLL management with immunotherapy: Investigating the potential of CAR T-cells and bispecific antibodies

Immunotherapies, such as chimeric antigen receptor (CAR) T-cell therapy and bispecific antibodies or T-cell engagers, have revolutionized the treatment landscape for various B-cell malignancies, including B-acute lymphoblastic leukemia and many non-Hodgkin lymphomas. Despite their significant impact on these malignancies, their application in chronic lymphocytic leukemia (CLL) management is still largely under investigation. Although the initial success of CD19-directed CAR T-cell therapy was observed in 3 multiply relapsed CLL patients, with 2 of them surviving over 10 years without relapse, recent CAR T-cell therapy trials in CLL have shown reduced response rates compared to their efficacy in other B-cell malignancies. One of the challenges with using immunotherapy in CLL is the compromised T-cell fitness from persistent CLL-related antigenic stimulation, and an immunosuppressive tumor microenvironment (TME). These challenges underscore a critical gap in therapeutic options for CLL patients intolerant or resistant to current therapies, emphasizing the imperative role of effective immunotherapy. Encouragingly, innovative strategies are emerging to overcome these challenges. These include integrating synergistic agents like ibrutinib to enhance CAR T-cell function and persistence and engineering newer CAR T-cell constructs targeting diverse antigens or employing dual-targeting approaches. Bispecific antibodies are an exciting "off-the-shelf" prospect for these patients, with their investigation in CLL currently entering the realm of clinical trials. Additionally, the development of allogeneic CAR T-cells and natural killer (NK) cells from healthy donors presents a promising solution to address the diminished T-cell fitness observed in CLL patients. This comprehensive review delves into the latest insights regarding the role of immunotherapy in CLL, the complex landscape of resistance mechanisms, and a spectrum of innovative approaches to surmount therapeutic challenges.

The rare DRB1*04:08-DQ8 haplotype is the main HLA class II genetic driver and discriminative factor of Early-onset Type 1 diabetes in the Portuguese population.

Early-onset Type 1 diabetes (EOT1D) is considered a disease subtype with distinctive immunological and clinical features. While both Human Leukocyte Antigen (HLA) and non-HLA variants contribute to age at T1D diagnosis, detailed analyses of EOT1D-specific genetic determinants are still lacking. This study scrutinized the involvement of the HLA class II locus in EOT1D genetic control. We conducted genetic association and regularized logistic regression analyses to evaluate genotypic, haplotypic and allelic variants in DRB1, DQA1 and DQB1 genes in children with EOT1D (diagnosed at ≤5 years of age; n=97), individuals with later-onset disease (LaOT1D; diagnosed 8-30 years of age; n=96) and nondiabetic control subjects (n=169), in the Portuguese population. Allelic association analysis of EOT1D and LaOT1D unrelated patients in comparison with controls, revealed that the rare DRB1*04:08 allele is a distinctive EOT1D susceptibility factor (corrected p-value=7.0x10-7). Conversely, the classical T1D risk allele DRB1*04:05 was absent in EOT1D children while was associated with LaOT1D (corrected p-value=1.4x10-2). In corroboration, HLA class II haplotype analysis showed that the rare DRB1*04:08-DQ8 haplotype is specifically associated with EOT1D (corrected p-value=1.4x10-5) and represents the major HLA class II genetic driver and discriminative factor in the development of early onset disease. This study uncovered that EOT1D holds a distinctive spectrum of HLA class II susceptibility loci, which includes risk factors overlapping with LaOT1D and discriminative genetic configurations. These findings warrant replication studies in larger multicentric settings encompassing other ethnicities and may impact target screening strategies and follow-up of young children with high T1D genetic risk as well as personalized therapeutic approaches.

Lateral Flow Immunochromatographic Assay for Competitive Detection of Crustacean Allergen Tropomyosin Using Phage-Displayed Shark Single-Domain Antibody.

The common food allergy crustacean tropomyosin (TM) poses a significant food safety challenge, which requires rapid and sensitive methods for screening TM in food. Herein, the variable new antigen receptor (VNAR) single-domain antibodies specific for the crustacean TM were isolated from a naïve phage-displayed shark VNAR library. Subsequently, a lateral flow immunochromatographic assay (LFIA) based on the gold nanoparticle-labeled phage-displayed shark VNAR (AuNPs@PSV) probe was developed for the detection of TM in food. The AuNPs@PSV-LFIA took 15 min for one test and had a visual limit of detection (vLOD) of 0.1 μg/mL and an instrumental LOD of 0.02 μg/mL. Good selectivity, accuracy, precision, and stability were confirmed for the AuNPs@PSV-LFIA. Moreover, the test results of 21 commercially available food products consisted of the allergen labels and were validated by a commercial ELISA kit. Therefore, this work demonstrated the great potential of VNAR for detecting TM in food by LFIA.

Molecular characterization of canine parvovirus type 2 (CPV2) reveals a high prevalence of the CPV2c genotype among dogs suffering from diarrhea

AbstractCanine parvovirus 2 (CPV-2) is a highly contagious virus in dogs that typically causes hemorrhagic enteritis and a high mortality rate in unvaccinated puppies. The genetic variability and antigenic diversity of CPV-2 hinder its effective prevention of infection by vaccination. To investigate the epidemiology and genetic characteristics of CPV-2 in China, rectal swabs from affected dogs were collected from different animal clinics in Kunshan from 2022 to 2023. Preliminary detection and capsid gene sequencing of CPV-2 were performed using previously described primers and protocols. The overall detection rate for CPV-2 was 16.5% (33/200). A significant association was found between the CPV-2-positivity and clinical signs, age, breed and vaccination status. Sequence analysis revealed the presence of CPV-2c genotypes in all positive samples, which were genetically similar to other Asian CPV-2c strains. Notably, four key mutations (A5G, F267Y, Y324I and Q370R) were detected in all isolates, and one novel mutation (I447M) was detected in three CPV-2 isolates. These mutations in the CPV-2 strains could impact vaccine efficacy and the effectiveness of the virus immune evasion. Surprisingly, no recombination events were observed between the identified CPV-2c strains and reference strains from China. Our data revealed that amino acid residues 324, 426 and 440 of VP2 may under strong selection pressure. This pattern of genetic variation in the CPV-2 lineage warrants continuous laboratory-based surveillance programs in other parts of China to better understand the pattern of seasonal distribution and association between emerging genotypes and the intensity of disease severity.

The Pathogenesis of Foot-and-Mouth Disease Virus Infection: How the Virus Escapes from Immune Recognition and Elimination.

Foot-and-mouth disease virus (FMDV) is a highly contagious and economically devastating pathogen that affects cloven-hoofed animals worldwide. FMDV infection causes vesicular lesions in the mouth, feet, and mammary glands, as well as severe systemic symptoms such as fever, salivation, and lameness. The pathogenesis of FMDV infection involves complex interactions between the virus and the host immune system, which determine the outcome of the disease. FMDV has evolved several strategies to evade immune recognition and elimination, such as antigenic variation, receptor switching, immune suppression, and subversion of innate and adaptive responses. This review paper summarizes the current knowledge on the pathogenesis of FMDV infection and the mechanisms of immune evasion employed by the virus. It also discusses the challenges and opportunities for developing effective vaccines and therapeutics against this important animal disease.

Elevation of Serum Prostate-Specific Antigen Levels in Males With Pulmonary Embolism.

Hypoxemia is a clinical characteristic of pulmonary embolism (PE). Hypoxemia is associated with variations in serum prostate-specific antigen (PSA) levels. Thus, the present study aimed to determine serum PSA levels in patients with PE, which may be helpful in improving clinical evaluation in screening for prostate diseases in those with PE. Clinical data from 61 consecutive male patients with PE and 113 age-matched healthy male controls were retrospectively analyzed. The pulmonary artery obstruction index (PAOI) was used to evaluate the pulmonary embolic burden. Compared with healthy controls, serum total PSA (tPSA) levels were significantly increased (P = .003), and free PSA (fPSA)/tPSA ratio was significantly decreased in patients with PE (P < .001). There was no significantly difference in serum fPSA levels between patients with PE and healthy controls (P = .253). A significant positive association was observed between serum tPSA levels and PAOI in patients with PE (β = .270, P = .036). Multivariable linear regression analysis revealed that serum tPSA levels were independently associated with PAOI in patients with PE (β = .347, P = .003). Serum tPSA levels were higher in male patients with PE than those in healthy controls, but fPSA was not affected. These findings highlight that PE may elevate serum tPSA levels, and that measures of tPSA should be interpreted with caution in screening for prostate diseases in patients with PE.

Whole-Mount Immunohistochemical and Immunofluorescence Assays in Zebrafish Embryos.

Zebrafish embryos are an important organism used as an in vivo model in a wide variety of disciplines from the past to the present. Immunohistochemistry analyses are an important method used to determine the localization of specific antigens in tissue sections with labeled antibodies depending on antigen-antibody interactions in zebrafish embryos. Immunofluorescence assays are an immunohistochemistry method that uses fluorophores to determine diverse cellular antigens. Zebrafish embryos and larvae, with their small size, are the most ideal model organisms for whole-mount immunohistochemical and immunofluorescent methods today. The small size of these organisms allows simultaneous evaluation of different tissues and organs, and results are obtained in a shorter time. In this section, whole-mount immunohistochemical and immunofluorescent analysis methods in zebrafish embryos, and larvae are summarized in detail, taking into account different studies and recent advances.

Analysis of Human Leukocyte Antigen Frequency among Renal Transplant Recipients and Donors in Nepal

ABSTRACT Background and Objectives: Kidney transplants are effective for advanced renal failure, but graft rejection can occur when the recipient’s immune system misidentifies the kidney as a foreign object. Human leukocyte antigen (HLA), a component of the host’s immunological defense system, acts as a barrier to graft rejection. Selecting potential kidney recipients and donors for transplantation requires careful consideration of histocompatibility for the HLA-A, HLA-B, and HLA-DRB1 antigens. Mismatches between donors and recipients prolong transplant therapy, leading to lower graft survival and higher mortality. The objective of the study was to analyze HLA-A, HLA-B, and HLA-DRB1 antigens frequency in live-related renal transplant recipients and donors visiting the Department of Histocompatibility and Immunopathology at the National Public Health Laboratory, Teku, Kathmandu, Nepal. Methods: A retrospective study was conducted by using data from 104 renal transplant recipients and donors whose samples had previously been collected, processed, and analyzed to identify the Class I loci (HLA-A and HLA-B) and Class II loci (DRB1) between November 2021 and February 2024. Results: The study found that the majority of donors were female, and the majority of recipients were male. In this study, 10, 17, and 12 different HLA-A, B, and DRB1 alleles were found in recipients and donors. Alleles found more frequently are A*11 (25.00%), A*24 (23.08%), sB*15 (22.60%), B*35 (12.98%), DRB1*15 (22.60%), and DRB1*12 (21.63%). Conclusions: The study suggests that both donors and recipients of renal transplants in Nepal have a diverse HLA antigen distribution, which could aid in selecting a genetically closer group as potential matched donors for transplant recipients.

A STUDY ON HOMOLOGY AND HETEROLOGY BETWEEN PANASIA-II &amp; PAK-98 LINEAGES OF FOOT AND MOUTH DISEASE VIRUS SEROTYPE-O

To understand the dynamics of epidemics, it is crucial to evaluate prior exposure to infectious diseases as a possible defense against newly developing strains. The cross-protection prediction is unresolved matter that holds great importance, particularly in the field of Foot-and-Mouth Disease Virus (FMDV). The new methods for controlling FMD involve the implementation of vaccine, limited movement, containment and elimination of cattle that are either affected or vulnerable to the disease. Therefore, it is necessary to use a serological analysis strategy that applies association coefficients (r1-values) to identify effective vaccines. The primary objective of this study was aimed to explain the genetic homologous and heterologous association among two ancestries of FMDV serotype O found in Pakistan (Pk) and to find a suitable strain from field for selection of vaccinated seed that provide cross-protection against both ancestries. Virus neutralization tests (VNTs) were used to evaluate an antigenic association among the two groups of viruses, indicates a significant degree of antigenic similarity between stains within a particular cluster. Conversely, r1 values ranging from 0.07-0.2 were obtained from cross-combinations among clusters, suggesting antigenic variation amongst virus strains. These results were further supported by in vitro tests, which showed that heterologous combinations of PanAsia-II and PAK-98 isolates showed antigenic variation, except for 25-06-PK-19, SDG-43-FSD-PK, and TANWL-34PK, which showed a 0.3 (r1 value). In contrast, when considering homologous combination of strains from both lineages showed antigenic similarity. Furthermore, it was projected that these combinations would provide protective titers during in-vivo. As a conclusion, it is recommended that all strains, except 25-06-PK-19, SDG-43-FSD-PK, and TANWL-34PK considered as potential vaccine candidates for effectively managing outbreaks of FMDV serotype-O, due to their ability to confer broad-spectrum immunity.

Past And Current Vaccine Development Effort of Gonorrhea

Neisseria gonorrhea causes gonorrhoea, which is one of the sexually transmitted infections (STI) diseases that can affect the health of women, men, and neonates. Reflecting on its history of treatment, the development and distribution of a vaccine hold significant potential for mitigating the impact of this disease, especially in vulnerable populations. However, developing a novel vaccine for Neisseria gonorrhoeae has posed considerable challenges. This is primarily due to the Gonorrhea's antigenic variation, rendering it difficult for the human immune system to identify. Neisseria Gonorrhea is currently exhibiting significant antimicrobial resistance, raising concerns about the potential for it to evolve into a superbug in the future. This escalating antimicrobial resistance has led to a diminishing effectiveness of antibiotics in treating Neisseria gonorrhoeae infections. Consequently, there is an increased risk of reinfection, potentially necessitating higher antibiotic doses during treatment. This, in turn, contributes to elevated treatment costs. Thus, the development of a new vaccine against Neisseria gonorrhoeae becomes imperative. This urgency is particularly pronounced for safeguarding the health of women and newborns. In this review, I explored the progress and efficacy of both historical and contemporary vaccines designed to address Neisseria gonorrhoeae infections.

The Relationship of ABO and Rh Blood Group Types With Severe COVID-19 Disease Mortality in ICU Patients: Insights From a Single-Center Experience in Southern Saudi Arabia.

Introduction The global COVID-19 pandemic has triggered an unprecedented public health crisis, emphasizing the need to understand factors influencing disease outcomes. This study explores the role of genetic variations in blood group antigens, particularly ABO and RhD, in shaping mortality rates among critically ill COVID-19 patients in the southern region of Saudi Arabia. Methods Utilizing a retrospective, noninterventional approach, we analyzed medical records of 594 COVID-19 patients admitted to the intensive care unit (ICU) at Aseer Central Hospital from August 2020 to April 2021. The cohort, with a mean age of 60.5 years, consisted of a predominantly male population. Results The study encompassed a diverse age range of 18 to 103 years, with a mean age of 60.5 ± 17.3 years. Of the 594 patients, 398 (67%) were male, and only 5 (0.8%) had a history of smoking. Blood group distribution revealed 275 (48.4%) with O-, 189 (33.3%) with A+, and 51 (9%) with AB- types. Predominant chronic conditions included diabetes mellitus (35.5%). Tragically, 320 patients (54.6%) experienced mortality, with a 100% mortality rate for the B+ blood group and 92.9% for O- blood group. Conclusion This analysis establishes significant statistical links, underscoring the pivotal role of blood type, particularly the Rh factor, in influencing mortality risk among critically ill COVID-19 patients. These findings contribute valuable insights into risk stratification and personalized care for severe cases, emphasizing the importance of genetic considerations in understanding disease outcomes.

Reticulocyte Binding Protein Homologue 5 is a target of balancing selection in the Plasmodium falciparum population of Papua New Guinea

Plasmodium falciparum Reticulocyte Binding Protein Homologue (RH5), a leading malaria vaccine candidate, is essential for erythrocyte invasion by the parasite, interacting with the human host receptor, basigin. RH5 has a small number of polymorphisms relative to other blood-stage antigens, and in vitro studies have shown that vaccine-induced antibodies raised against RH5 are strain-transcending, however most studies investigating RH5 diversity have been done in Africa. Understanding the genetic diversity and evolution of malaria antigens in other regions is important for their validation as vaccine candidates. In this study the rh5 gene was sequenced in 677 samples from a longitudinal cohort of Papua New Guinean (PNG) children aged 1-3 years. Of 677 samples successfully sequenced, 566 were identified as independent infections (i.e. one of each pair of identical sequences within hosts were removed). A total of 14 non-synonymous polymorphisms were identified, eight that are ‘common’ in the population (minor allele frequency &amp;gt; 1%), with 44 haplotypes ranging in frequency from 1% to 21%. Modeling of common SNPs to the cryo-EM structure of the RH5/CyRPA/RIPR complex mapped them to the Basigin binding site and near the contact point of CyRPA. Tajima’s D analyses of the corresponding nucleotide sequences produced positive values indicating potential hotspots of balancing selection. We attempted to confirm whether these signals were due to immune selection by measuring the rate of polymorphism between independent infections within the same host, and the association with clinical symptoms, however, no such associations were identified. Together these results suggest that while there is evidence of balancing selection driving RH5 diversity in the PNG P. falciparum population, immune escape was not observed within the cohort of young children. Limited immunity and therefore low selective pressure may explain this result, alternatively other evolutionary forces may contribute to balancing selection at the RH5-BSG binding interface in PNG.

Pre-treatment of canine plasma with heat, rather than acid, efficiently enhances Dirofilaria immitis antigen detection

BackgroundThe dissociation of antigen-antibody complexes has been utilized to enhance the accuracy of serological tests for infectious diseases, including Dirofilaria immitis. Currently, the antigen detected by available tests is primarily a glycoprotein found in the reproductive tract of female worms. However, this antigen can become inaccessible when bound to excessive circulating antibodies, leading to reduced test sensitivity and false-negative results. Acid and heat treatments of the sera or plasma have been established as reliable methods for inducing immune complex dissociation (ICD). Previous antigen testing for heartworm infection in dogs and cats has demonstrated that these treatments improve the diagnostic sensitivity without compromising specificity. This study aims to evaluate the performance of four distinct ICD methods in the detection of D. immitis antigen.MethodsWe utilized twofold serial dilutions of a well-characterized plasma (ranging from 1:2 to 1:4096) obtained from a D. immitis-infected dog to simulate the diverse antigen levels encountered in real-life infected dogs. The presence of antigen in the diluted samples, both without treatment and treated with four ICD protocols, was assessed in triplicate visually using DiroCHEK® by observing color changes. OD values were also obtained using the microplate reader SpectraMax® i Series-Spectramax Id3. A Factorial ANOVA test was conducted to compare the OD values between samples with and without treatments.ResultsThe highest dilution at which color changes were observed was 1:128 for untreated samples and for samples subjected to acid treatments in ICD-3 and the hybrid ICD-4 protocol. In contrast, both heat treatment protocols (ICD-1 and ICD-2) exhibited color changes at a 512-fold dilution. The OD values in samples subjected to heat treatment were significantly higher than those in untreated samples, up to dilutions of 512-fold. Although OD values tended to be higher in samples subjected to acid treatment and the hybrid protocol compared to untreated samples up to a 128-fold dilution, this difference was not significant as the samples underwent further dilution.ConclusionsOur findings affirm that heat treatments, rather than acid treatment, efficiently enhance the detection of D. immitis antigen by liberating the sequestered antigen from the immune complexes.

Microevolution and Its Impact on Hypervirulence, Antimicrobial Resistance, and Vaccine Escape in Neisseria meningitidis.

Neisseria meningitidis is commensal of the human pharynx and occasionally invades the host, causing the life-threatening illness invasive meningococcal disease. The meningococcus is a highly diverse and adaptable organism thanks to natural competence, a propensity for recombination, and a highly repetitive genome. These mechanisms together result in a high level of antigenic variation to invade diverse human hosts and evade their innate and adaptive immune responses. This review explores the ways in which this diversity contributes to the evolutionary history and population structure of the meningococcus, with a particular focus on microevolution. It examines studies on meningococcal microevolution in the context of within-host evolution and persistent carriage; microevolution in the context of meningococcal outbreaks and epidemics; and the potential of microevolution to contribute to antimicrobial resistance and vaccine escape. A persistent theme is the idea that the process of microevolution contributes to the development of new hyperinvasive meningococcal variants. As such, microevolution in this species has significant potential to drive future public health threats in the form of hypervirulent, antibiotic-resistant, vaccine-escape variants. The implications of this on current vaccination strategies are explored.

Advancement of Autogenous Vaccines in the Poultry Industry.

Autogenous vaccines, also known as "custom" vaccines, have become an essential instrument in the production veterinarian's toolbox for the control of emerging and evolving diseases. Autogenous vaccines require a reduced burden of U.S. Department of Agriculture licensing, making them rapidly accessible. Autogenous vaccines have made significant advancements in the ability to reduce disease within the poultry industry from a combination of several different advancements in regulation requirements, rapid and accurate diagnostic assessments, and improvements in manufacturing. The use of autogenous vaccines by poultry health professionals has also increased, and these custom-made products have been instrumental in combating diseases resulting from antigenic variants such as salmonellosis, colibacillosis, infectious coryza, infectious bursal disease, inclusion body hepatitis, viral enteritis, and viral arthritis and tenosynovitis.

Application of proteomics in identifying crucial virulence factors shared by different Streptococcus iniae isolates for developing an effective subunit vaccine against S. iniae in tilapia

Streptococcus iniae (S. iniae) has become an important aquatic pathogen to cause serious streptococcosis outbreaks in cultured fish species, thus resulting in great economic losses in the worldwide aquaculture industry. Although vaccination has been so far an effective strategy to alleviate the threats of streptococcosis, antigenic variations displayed by different strains/isolates of S. iniae have brought about a severe challenge in the vaccine development. In the present study, three local S. iniae isolates, MML SI-007, MML SI-018 and MML SI-148, were first evaluated for their virulence in tilapia. Proteomics was then performed to analyze protein profiles between the highly virulent isolate (MML SI-007) and lowly virulent isolate (MML SI-018) in order to identify important virulence factors/antigens shared by different isolates. After proteomics, eleven proteins that displayed more than four times the differences in expression between MML SI-007 and MML SI-018 were identified. Two proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and superoxide dismutase (SOD), were selected to be vaccine candidates for respectively cloning their genes and expressing their recombinant proteins, rGAPDH and rSOD. After peritoneal vaccination in tilapia, mixed recombinant proteins (rGAPDH + rSOD) elicited significantly higher serum titers and lymphocyte proliferation than individual recombinant proteins (rGAPDH or rSOD). In addition, maximum production of IL-6 in the head kidney was detected in fish peritoneally vaccinated with mixed recombinant proteins. More importantly, 84% (21/25) of tilapia peritoneally vaccinated with mixed recombinant proteins survived at least four weeks after a lethal peritoneal challenge of heterologous S. iniae (MML SI-148). Taken together, our results have pointed out that both GAPDH and SOD identified via proteomics are crucial virulence factors that can be protective antigens for future development of an effective cross-protective subunit vaccine against S. iniae.