The role of HLA-DR-DQ haplotypes in variable antibody responses to anthrax vaccine adsorbed

Genetic determinants of IgG antibody response to COVID-19 vaccination

Human humoral immune responses to SARS-CoV-2 vaccines exhibit substantial inter-individual variability and have been linked to vaccine efficacy. To elucidate the underlying mechanism behind this variability, we conducted a genome-wide association study (GWAS) on the anti-spike IgG serostatus of UK Biobank participants who were previously uninfected by SARS-CoV-2 and had received either the first dose (n = 54,066) or the second dose (n = 46,232) of COVID-19 vaccines. Our analysis revealed significant genome-wide associations between the IgG antibody serostatus following the initial vaccine and human leukocyte antigen (HLA) class II alleles. Specifically, the HLA-DRB1∗13:02 allele (MAF = 4.0%, OR = 0.75, p = 2.34e-16) demonstrated the most statistically significant protective effect against IgG seronegativity. This protective effect was driven by an alteration from arginine (Arg) to glutamic acid (Glu) at position 71 on HLA-DRβ1 (p = 1.88e-25), leading to a change in the electrostatic potential of pocket 4 of the peptide binding groove. Notably, the impact of HLA alleles on IgG responses was cell type specific, and we observed a shared genetic predisposition between IgG status and susceptibility/severity of COVID-19. These results were replicated within independent cohorts where IgG serostatus was assayed by two different antibody serology tests. Our findings provide insights into the biological mechanism underlying individual variation in responses to COVID-19 vaccines and highlight the need to consider the influence of constitutive genetics when designing vaccination strategies for optimizing protection and control of infectious disease across diverse populations.

The immunogenetics of COVID-19

The worldwide coronavirus disease 2019 pandemic was sparked by the severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) that first surfaced in December 2019 (COVID-19). The effects of COVID-19 differ substantially not just between patients individually but also between populations with different ancestries. In humans, the human leukocyte antigen (HLA) system coordinates immune regulation. Since HLA molecules are a major component of antigen-presenting pathway, they play an important role in determining susceptibility to infectious disease. It is likely that differential susceptibility to SARS-CoV-2 infection and/or disease course in COVID-19 in different individuals could be influenced by the variations in the HLA genes which are associated with various immune responses to SARS-CoV-2. A growing number of studies have identified a connection between HLA variation and diverse COVID-19 outcomes. Here, we review research investigating the impact of HLA on individual responses to SARS-CoV-2 infection and/or progression, also discussing the significance of MHC-related immunological patterns and its use in vaccine design.

Genetic predisposition to adverse events in Chinese children aged 3-24 months after diphtheria, tetanus, acellular pertussis and haemophilus influenzae type b combined vaccination

BACKGROUND

Post-vaccination safety is a major public health concern. The genetic predisposition on immune response has not been clearly identified. Clarifying whether individual genetic predisposition plays a role on adverse events (AEs) is critical for the prevention of AEs.

METHODS

From July 2019 to June 2020, we performed a case-control study among children aged 3-24 months in seven Chinese provinces. Each child received a combination vaccination against diphtheria, tetanus, acellular pertussis, and Haemophilus influenzae type b (DTaP-Hib). Through daily telephone follow-up, we collected AEs within seven days. Oral swab samples were collected to investigate the effects of single nucleotide polymorphisms (SNPs) on the risk of AEs.

RESULTS

304 participants were included in the study. In univariate analysis, we discovered three protective SNPs (rs452204, OR = 0.67, P = 0.0352; rs9282763 and rs839, OR = 0.64, P = 0.0256) and one risk SNP (rs9610, OR = 2.20, P = 0.0397). In multivariate analysis, the effects of rs452204 and rs839 were found to be stable. The interaction between rs452204 and rs9610 was observed (OR = 7.25, 95% CI: 1.44-36.58, P = 0.0165).

CONCLUSION

Genetic predisposition was associated with the risk of AEs after DTaP-Hib vaccination, emphasizing the potential application in the prevention of AEs.

Impact of HLA Polymorphism on the Immune Response to Bacillus Anthracis Protective Antigen in Vaccination versus Natural Infection

The causative agent of anthrax, Bacillus anthracis, evades the host immune response and establishes infection through the production of binary exotoxins composed of Protective Antigen (PA) and one of two subunits, lethal factor (LF) or edema factor (EF). The majority of vaccination strategies have focused upon the antibody response to the PA subunit. We have used a panel of humanised HLA class II transgenic mouse strains to define HLA-DR-restricted and HLA-DQ-restricted CD4+ T cell responses to the immunodominant epitopes of PA. This was correlated with the binding affinities of epitopes to HLA class II molecules, as well as the responses of two human cohorts: individuals vaccinated with the Anthrax Vaccine Precipitated (AVP) vaccine (which contains PA and trace amounts of LF), and patients recovering from cutaneous anthrax infections. The infected and vaccinated cohorts expressing different HLA types were found to make CD4+ T cell responses to multiple and diverse epitopes of PA. The effects of HLA polymorphism were explored using transgenic mouse lines, which demonstrated differential susceptibility, indicating that HLA-DR1 and HLA-DQ8 alleles conferred protective immunity relative to HLA-DR15, HLA-DR4 and HLA-DQ6. The HLA transgenics enabled a reductionist approach, allowing us to better define CD4+ T cell epitopes. Appreciating the effects of HLA polymorphism on the variability of responses to natural infection and vaccination is vital in planning protective strategies against anthrax.

Characterization of the UK anthrax vaccine and human immunogenicity

The manufacture of the UK Anthrax vaccine (AVP) focuses on the production of Protective Antigen (PA) from the Bacillus anthracis Sterne strain. Although used for decades, several of AVP’s fundamental properties are poorly understood, including its exact composition, the extent to which proteins other than PA may contribute to protection, and whether the degree of protection varies between individuals.

This study involved three innovative investigations. Firstly, the composition of AVP was analyzed using liquid chromatography tandem mass-spectrometry (LC-MS/MS), requiring the development of a novel desorption method for releasing B. anthracis proteins from the vaccine’s aluminum-containing adjuvant. Secondly, computational MHC-binding predictions using NetMHCIIpan were made for the eight most abundant proteins of AVP, for the commonest HLA alleles in multiple ethnic groups, and for multiple B. anthracis strains. Thirdly, antibody levels and toxin neutralizing antibody (TNA) levels were measured in sera from AVP human vaccinees for both PA and Lethal Factor (LF).

It was demonstrated that AVP is composed of at least 138 B. anthracis proteins, including PA (65%), LF (8%) and Edema Factor (EF) (3%), using LC-MS/MS. NetMHCIIpan predicted that peptides from all eight abundant proteins are likely to be presented to T cells, a pre-requisite for protection; however, the number of such peptides varied considerably between different HLA alleles.

These analyses highlight two important properties of the AVP vaccine that have not been established previously. Firstly, the effectiveness of AVP within humans may not depend on PA alone; there is compelling evidence to suggest that LF has a protective role, with computational predictions suggesting that additional proteins may be important for individuals with specific HLA allele combinations. Secondly, in spite of differences in the sequences of key antigenic proteins from different B. anthracis strains, these are unlikely to affect the cross-strain protection afforded by AVP.

Genomics and High-Consequence Infectious Diseases: A Scoping Review of Emerging Science and Potential Ethical Issues

Host genomic research on high-consequence infectious diseases is a growing area, but the ethical, legal, and social implications of such findings related to potential applications of the research have not yet been identified. While there is a robust ethical debate about the ethical, legal, and social implications of research during an emergency, there has been less consideration of issues facing research conducted outside of the scope of emergency response. Addressing the implications of research at an early stage (anticipatory ethics) helps define the issue space, facilitates preparedness, and promotes ethically and socially responsible practices. To lay the groundwork for more comprehensive anticipatory ethics work, this article provides a preliminary assessment of the state of the field with a scoping review of host genomic research on a subset of high-consequence infectious diseases of relevance to high-level isolation units, focusing on its ethically relevant features and identifying several ethical, legal, and social implications raised by the literature. We discuss the challenges of genomic studies of low-frequency, high-risk events and applications of the science, including identifying targets to guide the development of new therapeutics, improving vaccine development, finding biomarkers to predict disease outcome, and guiding decisions about repurposing existing drugs and genetic screening. Some ethical, legal, and social implications identified in the literature included the rise of systems biology and paradigm shifts in medical countermeasure development; controversies over repurposing of existing drugs; genetic privacy and discrimination; and benefit-sharing and global inequity as part of the broader ecosystem surrounding high-level isolation units. Future anticipatory ethics work should forecast the science and its applications; identify a more comprehensive list of ethical, legal, and social implications; and facilitate evaluation by multiple stakeholders to inform the integration of ethical concerns into high-level isolation unit policy and practice.

Protection of rhesus macaques against inhalational anthrax with a Bacillus anthracis capsule conjugate vaccine

The efficacy of currently licensed anthrax vaccines is largely attributable to a single Bacillus anthracis immunogen, protective antigen. To broaden protection against possible strains resistant to protective antigen-based vaccines, we previously developed a vaccine in which the anthrax polyglutamic acid capsule was covalently conjugated to the outer membrane protein complex of Neisseria meningitidis serotype B and demonstrated that two doses of 2.5μg of this vaccine conferred partial protection of rhesus macaques against inhalational anthrax . Here, we demonstrate complete protection of rhesus macaques against inhalational anthrax with a higher 50μg dose of the same capsule conjugate vaccine. These results indicate that B. anthracis capsule is a highly effective vaccine component that should be considered for incorporation in future generation anthrax vaccines.

Recent developments in the understanding and use of anthrax vaccine adsorbed: achieving more with less

Anthrax Vaccine Adsorbed (AVA, BioThrax™) is the only Food and Drug Administration (FDA) approved vaccine for the prevention of anthrax in humans. Recent improvements in pre-exposure prophylaxis (PrEP) use of AVA include intramuscular (IM) administration and simplification of the priming series to three doses over 6 months. Administration IM markedly reduced the frequency, severity and duration of injection site reactions. Refinement of animal models for inhalation anthrax, identification of immune correlates of protection and cross-species modeling have created opportunities for reductions in the PrEP booster schedule and were pivotal in FDA approval of a post-exposure prophylaxis (PEP) indication. Clinical and nonclinical studies of accelerated PEP schedules and divided doses may provide prospects for shortening the PEP antimicrobial treatment period. These data may assist in determining feasibility of expanded coverage in a large-scale emergency when vaccine demand may exceed availability. Enhancements to the AVA formulation may broaden the vaccine's PEP application.

An initial investigation of associations between dopamine-linked genetic variation and smoking motives in African Americans

Nicotine dependence (ND) is a heterogeneous phenotype with complex genetic influences that may vary across ethnicities. The use of intermediate phenotypes may clarify genetic influences and reveal specific etiological pathways. Prior work in European Americans has found that the four Primary Dependence Motives (PDM) subscales (Automaticity, Craving, Loss of Control, and Tolerance) of the Wisconsin Inventory of Smoking Motives represent core features of nicotine dependence and are promising intermediate phenotypes for understanding genetic pathways to ND. However, no studies have examined PDM as an intermediate phenotype in African American smokers, an ethnic population that displays unique patterns of smoking and genetic variation. In the current study, 268 African American daily smokers completed a phenotypic assessment and provided a sample of DNA. Associations among haplotypes in the NCAM1-TTC12-ANKK1-DRD2 gene cluster, a dopamine-related gene region associated with ND, PDM intermediate phenotypes, and ND were examined. Dopamine-related genetic variation in the DBH and COMT genes was also considered on an exploratory basis. Mediational analysis was used to test the indirect pathway from genetic variation to smoking motives to nicotine dependence. NCAM1-TTC12-ANKK1-DRD2 region variation was significantly associated with the Automaticity subscale and, further, Automaticity significantly mediated associations among NCAM1-TTC12-ANKK1-DRD2 cluster variants and ND. DBH was also significantly associated with Automaticity, Craving, and Tolerance; Automaticity and Tolerance also served as mediators of the DBH-ND relationship. These results suggest that PDM, Automaticity in particular, may be a viable intermediate phenotype for understanding dopamine-related genetic influences on ND in African American smokers. Findings support a model in which putatively dopaminergic variants exert influence on ND through an effect on patterns of automatic routinized smoking.

HLA Class-II Associated HIV Polymorphisms Predict Escape from CD4+ T Cell Responses

Antiretroviral therapy, antibody and CD8⁺ T cell-mediated responses targeting human immunodeficiency virus-1 (HIV-1) exert selection pressure on the virus necessitating escape; however, the ability of CD4⁺ T cells to exert selective pressure remains unclear. Using a computational approach on HIV gag/pol/nef sequences and HLA-II allelic data, we identified 29 HLA-II associated HIV sequence polymorphisms or adaptations (HLA-AP) in an African cohort of chronically HIV-infected individuals. Epitopes encompassing the predicted adaptation (AE) or its non-adapted (NAE) version were evaluated for immunogenicity. Using a CD8-depleted IFN-γ ELISpot assay, we determined that the magnitude of CD4⁺ T cell responses to the predicted epitopes in controllers was higher compared to non-controllers (p<0.0001). However, regardless of the group, the magnitude of responses to AE was lower as compared to NAE (p<0.0001). CD4⁺ T cell responses in patients with acute HIV infection (AHI) demonstrated poor immunogenicity towards AE as compared to NAE encoded by their transmitted founder virus. Longitudinal data in AHI off antiretroviral therapy demonstrated sequence changes that were biologically confirmed to represent CD4⁺ escape mutations. These data demonstrate an innovative application of HLA-associated polymorphisms to identify biologically relevant CD4⁺ epitopes and suggests CD4⁺ T cells are active participants in driving HIV evolution.

In HIV, CD4⁺ T cells are best known as the primary targets of infection. Although emerging data has suggested a more active role in viral pathogenesis, the CD4⁺ T cell population remains relatively understudied. Using a novel computational approach, we predicted 29 different epitopes with mutations that potentially represent escape from CD4⁺ T cell responses. The predicted escaped epitopes were found to be less immunogenic than the wild type forms, suggesting that the identified escapes allow HIV to reduce its visibility to the immune system. Using longitudinal samples, we were able to show CD4⁺ T cells driving viral escape following acute infection. Overall, these findings significantly expand our knowledge of how CD4⁺ T cells can exert HIV control and influence HIV evolution, providing important implications to future vaccine development strategies.

Adversomics: a new paradigm for vaccine safety and design

Despite the enormous population benefits of routine vaccination, vaccine adverse events (AEs) and reactions, whether real or perceived, have posed one of the greatest barriers to vaccine acceptance--and thus to infectious disease prevention--worldwide. A truly integrated clinical, translational, and basic science approach is required to understand the mechanisms behind vaccine AEs, predict them, and then apply this knowledge to new vaccine design approaches that decrease, or avoid, these events. The term 'adversomics' was first introduced in 2009 and refers to the study of vaccine adverse reactions using immunogenomics and systems biology approaches. In this review, we present the current state of adversomics research, review known associations and mechanisms of vaccine AEs/reactions, and outline a plan for the further development of this emerging research field.

Correlation of HLA-DQB1 gene polymorphism of Xinjiang Uygur with outcome of HBV infection

BACKGROUND

The aim of this study was to explore the correlation of gene polymorphisms of human leukocyte antigen-DQB1 (HLA-DQB1) with the infection outcome and replication status of hepatitis B virus (HBV) positive patients in the Xinjiang Uygur population in China.

METHODS

110 cases of chronic hepatitis B (CHB) of Xinjiang Uygur were examined clinically, which were named as the CHB group; 100 cases carrying chronic HBV (ASC) served as ASC group; 80 cases of self-limited HBV infection (RHBS) were recorded as RHBS group. Genotypes of HLA-DQB1 were detected by sequence specific primer-polymerase chain reaction (PCR-SSP) method, and the differences of gene frequency among groups were also compared. The distribution frequencies of the HLA-DQB1 gene under different replication states of HBV were compared.

RESULTS

The distribution frequency of DQB1*0201 in the RHBS group was higher than that of the ASC group (18.75%, 10.50%, χ(2) = 5.959, P < 0.05, OR = 2.257). The distribution frequency of DQB1*0201 in the CHB group was higher than that of the ASC group (17.73%, 10.50%, χ(2) = 5.363, P < 0.05, OR = 2.066). The distribution frequency of DQB1*0301 in the CHB group was higher than that of the ASC group (26.82%, 16.50%, χ(2) = 9.062, P < 0.05, OR = 2.349). The distribution frequency of DQB1*0303 in the CHB group was lower than that of the ASC group (19.55%, 31.00%, χ(2) = 10.996, P < 0.05, OR = 0.393). There was no statistically significant difference in the allele frequencies among all other groups. The distribution frequency of DQB1*0201 in the low replication group was higher than that of the high replication group (17.08%, 10.56%, χ(2) = 4.295, P < 0.05, OR = 1.939).

CONCLUSION

HLA-DQB1*0201 is a HBV resistance gene in Xinjiang Uygur. DQB1*0301 is correlated with continuous infection of HBV. DQB1*0303 is a susceptibility gene of ASC.

NCAM1-TTC12-ANKK1-DRD2 variants and smoking motives as intermediate phenotypes for nicotine dependence

RATIONALE

Nicotine dependence (ND) is a heterogeneous phenotype with complex genetic influences. The use of intermediate ND phenotypes may clarify genetic influences and reveal specific etiological pathways. Prior work has found that the four Primary Dependence Motives (PDM) subscales (Automaticity, Craving, Loss of Control, and Tolerance) of the Wisconsin Inventory of Smoking Motives (WISDM) represent heavy, pervasive smoking, which is a core feature of nicotine dependence, making these motives strong candidates as intermediate phenotypes.

OBJECTIVE

This study examines the WISDM PDM as a novel intermediate phenotype of nicotine dependence.

METHODS

The study used data from 734 European Americans who smoked at least 5 cigs/day [M = 16.2 (SD = 9.5) cigs/day], completed a phenotypic assessment, and provided a sample of DNA. Based on prior evidence of the role of genetic variation in the NCAM1-TTC12-ANKK1-DRD2 region on chromosome 11q23 in smoking behavior, associations among 12 region loci with nicotine dependence and PDM phenotypes were examined using haplotype and individual loci approaches. In addition, mediational analysis tested the indirect pathway from genetic variation to smoking motives to nicotine dependence.

RESULTS

NCAM1-TTC12-ANKK1-DRD2 region loci and haplotypes were significantly associated with the motive of Automaticity and, further, Automaticity significantly mediated associations among NCAM1-TTC12-ANKK1-DRD2 cluster variants and nicotine dependence.

CONCLUSIONS

These results suggest that motives related to automaticity are a viable intermediate phenotype for understanding genetic contributions to nicotine dependence. Further, NCAM1-TTC12-ANKK1-DRD2 variants may increase the likelihood that a person will become dependent via a highly automatic smoking ritual that can be elicited with little awareness.

Host immunity to Bacillus anthracis lethal factor and other immunogens: implications for vaccine design

Infections of humans with Bacillus anthracis are an issue with respect to the biothreat both to civilians and military personnel, infections of individuals by infected livestock in endemic regions and, recently, infections of intravenous drug users injecting anthrax-contaminated heroin. Existing vaccination regimens are reliant on protective antigen neutralization induced by repeated boosts with the AVA or AVP vaccines. However, there is ongoing interest in updated approaches in light of the intensive booster regime and extent of reactogenicity inherent in the current protocols. Several other immunogens from the B. anthracis proteome have been characterized in recent years, including lethal factor. Lethal factor induces strong CD4 T-cell immunity and encompasses immunodominant epitopes of relevance across diverse HLA polymorphisms. Taken together, recent studies emphasize the potential benefits of vaccines able to confer synergistic immunity to protective antigen and to other immunogens, targeting both B-cell and T-cell repertoires.

Humoral responses to independent vaccinations are correlated in healthy boosted adults

BACKGROUND

Roughly half of U.S. adults do not receive recommended booster vaccinations, but protective antibody levels are rarely measured in adults. Demographic factors, vaccination history, and responses to other vaccinations could help identify at-risk individuals. We sought to characterize rates of seroconversion and determine associations of humoral responses to multiple vaccinations in healthy adults.

METHODS

Humoral responses toward measles, mumps, tetanus toxoid, pertussis, hepatitis B surface antigen, and anthrax protective antigen were measured by ELISA in post-immunization samples from 1465 healthy U.S. military members. We examined the effects of demographic and clinical factors on immunization responses, as well as assessed correlations between vaccination responses.

RESULTS

Subsets of boosted adults did not have seroprotective levels of antibodies toward measles (10.4%), mumps (9.4%), pertussis (4.7%), hepatitis B (8.6%) or protective antigen (14.4%) detected. Half-lives of antibody responses were generally long (>30 years). Measles and mumps antibody levels were correlated (r=0.31, p<0.001), but not associated with select demographic features or vaccination history. Measles and mumps antibody levels also correlated with tetanus antibody response (r=0.11, p<0.001).

CONCLUSIONS

Vaccination responses are predominantly robust and vaccine specific. However, a small but significant portion of the vaccinated adult population may not have quantitative seroprotective antibody to common vaccine-preventable infections.

HLA alleles associated with the adaptive immune response to smallpox vaccine: a replication study

We previously reported HLA allelic associations with vaccinia virus (VACV)-induced adaptive immune responses in a cohort of healthy individuals (n = 1,071 subjects) after a single dose of the licensed smallpox (Dryvax) vaccine. This study demonstrated that specific HLA alleles were significantly associated with VACV-induced neutralizing antibody (NA) titers (HLA-B*13:02, *38:02, *44:03, *48:01, and HLA-DQB1*03:02, *06:04) and cytokine (HLA-DRB1*01:03, *03:01, *10:01, *13:01, *15:01) immune responses. We undertook an independent study of 1,053 healthy individuals and examined associations between HLA alleles and measures of adaptive immunity after a single dose of Dryvax-derived ACAM2000 vaccine to evaluate previously discovered HLA allelic associations from the Dryvax study and determine if these associations are replicated with ACAM2000. Females had significantly higher NA titers than male subjects in both study cohorts [median ID50 discovery cohort 159 (93, 256) vs. 125 (75, 186), p < 0.001; replication cohort 144 (82, 204) vs. 110 (61, 189), p = 0.024]. The association between the DQB1*03:02 allele (median ID50 discovery cohort 152, p = 0.015; replication cohort 134, p = 0.010) and higher NA titers was replicated. Two HLA associations of comparable magnitudes were consistently found between DRB1*04:03 and DRB1*08:01 alleles and IFN-γ ELISPOT responses. The association between the DRB1*15:01 allele with IFN-γ secretion was also replicated (median pg/mL discovery cohort 182, p = 0.052; replication cohort 203, p = 0.014). Our results suggest that smallpox vaccine-induced adaptive immune responses are significantly influenced by HLA gene polymorphisms. These data provide information for functional studies and design of novel candidate smallpox vaccines.

Allelic-dependent expression of an activating Fc receptor on B cells enhances humoral immune responses

B cells are pivotal regulators of acquired immune responses, and recent work in both experimental murine models and humans has demonstrated that subtle changes in the regulation of B cell function can substantially alter immunological responses. The balance of negative and positive signals in maintaining an appropriate B cell activation threshold is critical in B lymphocyte immune tolerance and autoreactivity. FcγRIIb (CD32B), the only recognized Fcγ receptor on B cells, provides immunoglobulin G (IgG)-mediated negative modulation through a tyrosine-based inhibition motif, which down-regulates B cell receptor-initiated signaling. These properties make FcγRIIb a promising target for antibody-based therapy. We report the discovery of allele-dependent expression of the activating FcγRIIc on B cells. Identical to FcγRIIb in the extracellular domain, FcγRIIc has a tyrosine-based activation motif in its cytoplasmic domain. In both human B cells and B cells from mice transgenic for human FcγRIIc, FcγRIIc expression counterbalances the negative feedback of FcγRIIb and enhances humoral responses to immunization in mice and to BioThrax vaccination in a human anthrax vaccine trial. Moreover, the FCGR2C-ORF allele is associated with the risk of development of autoimmunity in humans. FcγRIIc expression on B cells challenges the prevailing paradigm of unidirectional negative feedback by IgG immune complexes via the inhibitory FcγRIIb, is a previously unrecognized determinant in human antibody/autoantibody responses, and opens the opportunity for more precise personalized use of B cell-targeted antibody-based therapy.

Immunogenicity and safety of a single dose of a CRM-conjugated meningococcal ACWY vaccine in children and adolescents aged 2-18 years in Taiwan: results of an open label study

BACKGROUND

MenACWY-CRM (Menveo®, Novartis Vaccines, Siena, Italy) is a quadrivalent meningococcal conjugate vaccine developed to help prevent invasive meningococcal disease caused by Neisseria meningitidis serogroups A, C, W, and Y. It is approved within the European Union in persons >2 years of age and in persons from 2 months to 55 years of age in the United States, among other countries. Little is known about the immunogenicity and safety of this vaccine in Taiwanese children >2 years and adolescents. This study assessed the immunogenicity and safety of a single injection of MenACWY-CRM vaccine in Taiwanese subjects aged 2-18 years old.

METHODS

In this phase III, multicentre, open-label study 341 subjects received one dose of MenACWY-CRM. Immunogenicity measures were rates of seroresponse (defined as the proportion of subjects with a postvaccination hSBA ≥1:8 if the prevaccination (baseline) titre was <1:4, or at least a fourfold higher hSBA titre than baseline if the prevaccination titre was ≥1:4), percentages of subjects with serum bactericidal activity (hSBA) ≥1:8 for serogroups A, C, W and Y and hSBA geometric mean titres (GMTs). Local and systemic reactions and all adverse events (AEs) were recorded for 7 days, and medically attended AEs for 1 month post-vaccination.

RESULTS

Seroresponse rates after MenACWY-CRM vaccination at Day 29 for the serogroups A, C, W, and Y were 83%, 93%, 50%, and 65%, respectively. At Day 29 the percentages of subjects with hSBA ≥1:8 against all four serogroups A, C, W and Y were: 83%, 96%, 96% and 82%, respectively. GMTs against all serogroups rose by ≥7-fold from baseline to Day 29. The vaccine was well tolerated.

CONCLUSIONS

A single dose of MenACWY-CRM demonstrated a robust immune response, and an acceptable safety profile in Taiwanese children and adolescents.

Impulsivity, variation in the cannabinoid receptor (CNR1) and fatty acid amide hydrolase (FAAH) genes, and marijuana-related problems

OBJECTIVE

Impulsivity is associated with increased marijuana use and subsequent marijuana-related problems among marijuana users. In addition, single nucleotide polymorphisms (SNPs) in the cannabinoid receptor 1 (CNR1) and fatty acid amide hydrolase (FAAH) genes have been associated with cannabis-related phenotypes. This exploratory study tested whether the association between different aspects of impulsivity and the number of marijuana-related problems among users is explicated by variation in these putative cannabinoid-related genes.

METHOD

A total of 151 young adult regular marijuana users (used on M= 41.4% of the prior 60 days, SD = 24.3%) provided DNA and completed measures of trait (Barratt Impulsiveness Scale) and behavioral impulsivity (Stop Signal Task and Delay Discounting Questionnaire), as well as a self-report of marijuana-related problems. Three CNR1 and five FAAH SNPs were genotyped, tested for haplotype blocks, and subsequently examined for association with phenotypes described above.

RESULTS

CNR1 variation significantly moderated the association between trait-level, but not behavioral, impulsivity and marijuana-related problems, such that the combination of higher trait impulsivity and CNR1 variation was associated with a greater number of marijuana-related problems. In contrast, there were no significant FAAH by impulsivity interactions; however, there was a main effect of FAAH on marijuana-related problems.

CONCLUSIONS

These findings support an association with CNR1 and FAAH genes and marijuana-related problems among regular marijuana users. CNR1 variation emerged as a moderator of the relationship between trait impulsivity and marijuana problems, thus suggesting that marijuana users with CNR1 risk variants and a higher trait impulsivity are at greater risk for developing marijuana-related problems and supporting a role for CNR1 in a broader impulsivity phenotype.

Anthrax lethal factor as an immune target in humans and transgenic mice and the impact of HLA polymorphism on CD4+ T cell immunity

Bacillus anthracis produces a binary toxin composed of protective antigen (PA) and one of two subunits, lethal factor (LF) or edema factor (EF). Most studies have concentrated on induction of toxin-specific antibodies as the correlate of protective immunity, in contrast to which understanding of cellular immunity to these toxins and its impact on infection is limited. We characterized CD4⁺ T cell immunity to LF in a panel of humanized HLA-DR and DQ transgenic mice and in naturally exposed patients. As the variation in antigen presentation governed by HLA polymorphism has a major impact on protective immunity to specific epitopes, we examined relative binding affinities of LF peptides to purified HLA class II molecules, identifying those regions likely to be of broad applicability to human immune studies through their ability to bind multiple alleles. Transgenics differing only in their expression of human HLA class II alleles showed a marked hierarchy of immunity to LF. Immunogenicity in HLA transgenics was primarily restricted to epitopes from domains II and IV of LF and promiscuous, dominant epitopes, common to all HLA types, were identified in domain II. The relevance of this model was further demonstrated by the fact that a number of the immunodominant epitopes identified in mice were recognized by T cells from humans previously infected with cutaneous anthrax and from vaccinated individuals. The ability of the identified epitopes to confer protective immunity was demonstrated by lethal anthrax challenge of HLA transgenic mice immunized with a peptide subunit vaccine comprising the immunodominant epitopes that we identified.

Anthrax is of concern with respect to human exposure in endemic regions, concerns about bioterrorism and the considerable global burden of livestock infections. The immunology of this disease remains poorly understood. Vaccination has been based on B. anthracis filtrates or attenuated spore-based vaccines, with more recent trials of next-generation recombinant vaccines. Approaches generally require extensive vaccination regimens and there have been concerns about immunogenicity and adverse reactions. An ongoing need remains for rationally designed, effective and safe anthrax vaccines. The importance of T cell stimulating vaccines is inceasingly recognized. An essential step is an understanding of immunodominant epitopes and their relevance across the diverse HLA immune response genes of human populations. We characterized CD4 T cell immunity to anthrax Lethal Factor (LF), using HLA transgenic mice, as well as testing candidate peptide epitopes for binding to a wide range of HLA alleles. We identified anthrax epitopes, noteworthy in that they elicit exceptionally strong immunity with promiscuous binding across multiple HLA alleles and isotypes. T cell responses in humans exposed to LF through either natural anthrax infection or vaccination were also examined. Epitopes identified as candidates were used to protect HLA transgenic mice from anthrax challenge.

Associations between race, sex and immune response variations to rubella vaccination in two independent cohorts

INTRODUCTION

Immune response variations after vaccination are influenced by host genetic factors and demographic variables, such as race, ethnicity and sex. The latter have not been systematically studied in regard to live rubella vaccine, but are of interest for developing next generation vaccines for diverse populations, for predicting immune responses after vaccination, and for better understanding the variables that impact immune response.

METHODS

We assessed associations between demographic variables, including race, ethnicity and sex, and rubella-specific neutralizing antibody levels and secreted cytokines (IFNγ, IL-6) in two independent cohorts (1994 subjects), using linear and linear mixed models approaches, and genetically defined racial and ethnic categorizations.

RESULTS

Our replicated findings in two independent, large, racially diverse cohorts indicate that individuals of African descent have significantly higher rubella-specific neutralizing antibody levels compared to individuals of European descent and/or Hispanic ethnicity (p<0.001).

CONCLUSION

Our study provides consistent evidence for racial/ethnic differences in humoral immune response following rubella vaccination.

Genetic variants within the MHC region are associated with immune responsiveness to childhood vaccinations

The influence of genetic variability within the major histocompatibility complex (MHC) region on variations in immune responses to childhood vaccination was investigated. The study group consisted of 135 healthy infants who had been immunized with hepatitis B (HBV), 7-valent pneumococcal conjugate (PCV7), and diphtheria, tetanus, acellular pertussis (DTaP) vaccines according to standard childhood immunization schedules. Genotype analysis was performed on genomic DNA using Illumina Goldengate MHC panels (Mapping and Exon Centric). At the 1 year post vaccination check-up total, isotypic, and antigen-specific serum antibody levels were measured using multiplex immunoassays. A number of single nucleotide polymorphisms (SNPs) within MHC Class I and II genes were found to be associated with variations in the vaccine specific antibody responses and serum levels of immunoglobulins (IgG, IgM) and IgG isotypes (IgG1, IgG4) (all at p<0.001). Linkage disequilibrium patterns and functional annotations showed that significant SNPs were strongly correlated with other functional regulatory SNPs. These SNPs were found to regulate the expression of a group of genes involved in antigen processing and presentation including HLA-A, HLA-C, HLA-G, HLA-H, HLA-DRA, HLA-DRB1, HLA-DRB5, HLA-DQA1, HLA-DQB1, HLA-DOB, and TAP-2. The results suggest that genetic variations within particular MHC genes can influence immune response to common childhood vaccinations, which in turn may influence vaccine efficacy.

Human leukocyte antigens and cellular immune responses to anthrax vaccine adsorbed

Interindividual variations in vaccine-induced immune responses are in part due to host genetic polymorphisms in the human leukocyte antigen (HLA) and other gene families. This study examined associations between HLA genotypes, haplotypes, and homozygosity and protective antigen (PA)-specific cellular immune responses in healthy subjects following immunization with Anthrax Vaccine Adsorbed (AVA). While limited associations were observed between individual HLA alleles or haplotypes and variable lymphocyte proliferative (LP) responses to AVA, analyses of homozygosity supported the hypothesis of a "heterozygote advantage." Individuals who were homozygous for any HLA locus demonstrated significantly lower PA-specific LP than subjects who were heterozygous at all eight loci (median stimulation indices [SI], 1.84 versus 2.95, P = 0.009). Similarly, we found that class I (HLA-A) and class II (HLA-DQA1 and HLA-DQB1) homozygosity was significantly associated with an overall decrease in LP compared with heterozygosity at those three loci. Specifically, individuals who were homozygous at these loci had significantly lower PA-specific LP than subjects heterozygous for HLA-A (median SI, 1.48 versus 2.13, P = 0.005), HLA-DQA1 (median SI, 1.75 versus 2.11, P = 0.007), and HLA-DQB1 (median SI, 1.48 versus 2.13, P = 0.002) loci, respectively. Finally, homozygosity at an increasing number (≥ 4) of HLA loci was significantly correlated with a reduction in LP response (P < 0.001) in a dose-dependent manner. Additional studies are needed to reproduce these findings and determine whether HLA-heterozygous individuals generate stronger cellular immune response to other virulence factors (Bacillus anthracis LF and EF) than HLA-homozygous subjects.

Vaccinomics, adversomics, and the immune response network theory: individualized vaccinology in the 21st century

Vaccines, like drugs and medical procedures, are increasingly amenable to individualization or personalization, often based on novel data resulting from high throughput "omics" technologies. As a result of these technologies, 21st century vaccinology will increasingly see the abandonment of a "one size fits all" approach to vaccine dosing and delivery, as well as the abandonment of the empiric "isolate-inactivate-inject" paradigm for vaccine development. In this review, we discuss the immune response network theory and its application to the new field of vaccinomics and adversomics, and illustrate how vaccinomics can lead to new vaccine candidates, new understandings of how vaccines stimulate immune responses, new biomarkers for vaccine response, and facilitate the understanding of what genetic and other factors might be responsible for rare side effects due to vaccines. Perhaps most exciting will be the ability, at a systems biology level, to integrate increasingly complex high throughput data into descriptive and predictive equations for immune responses to vaccines. Herein, we discuss the above with a view toward the future of vaccinology.

Genomic copy number variants: evidence for association with antibody response to anthrax vaccine adsorbed

Background

Anthrax and its etiologic agent remain a biological threat. Anthrax vaccine is highly effective, but vaccine-induced IgG antibody responses vary widely following required doses of vaccinations. Such variation can be related to genetic factors, especially genomic copy number variants (CNVs) that are known to be enriched among genes with immunologic function. We have tested this hypothesis in two study populations from a clinical trial of anthrax vaccination.

Methods

We performed CNV-based genome-wide association analyses separately on 794 European Americans and 200 African-Americans. Antibodies to protective antigen were measured at week 8 (early response) and week 30 (peak response) using an enzyme-linked immunosorbent assay. We used DNA microarray data (Affymetrix 6.0) and two CNV detection algorithms, hidden markov model (PennCNV) and circular binary segmentation (GeneSpring) to determine CNVs in all individuals. Multivariable regression analyses were used to identify CNV-specific associations after adjusting for relevant non-genetic covariates.

Results

Within the 22 autosomal chromosomes, 2,943 non-overlapping CNV regions were detected by both algorithms. Genomic insertions containing HLA-DRB5, DRB1 and DQA1/DRA genes in the major histocompatibility complex (MHC) region (chromosome 6p21.3) were moderately associated with elevated early antibody response (β = 0.14, p = 1.78×10⁻³) among European Americans, and the strongest association was observed between peak antibody response and a segmental insertion on chromosome 1, containing NBPF4, NBPF5, STXMP3, CLCC1, and GPSM2 genes (β = 1.66, p = 6.06×10⁻⁵). For African-Americans, segmental deletions spanning PRR20, PCDH17 and PCH68 genes on chromosome 13 were associated with elevated early antibody production (β = 0.18, p = 4.47×10⁻⁵). Population-specific findings aside, one genomic insertion on chromosome 17 (containing NSF, ARL17 and LRRC37A genes) was associated with elevated peak antibody response in both populations.

Conclusion

Multiple CNV regions, including the one consisting of MHC genes that is consistent with earlier research, can be important to humoral immune responses to anthrax vaccine adsorbed.

Characterizing vaccine responses using host genomic and transcriptomic analysis

Vaccines have had a profound influence on human health with no other health intervention rivaling their impact on the morbidity and mortality associated with infectious disease. However, the magnitude and persistence of vaccine immunity varies considerably between individuals, a phenomenon that is not well understood. Recent studies have used contemporary technologies to correlate variation in the genome and transcriptome to immunological measures of vaccine responsiveness. These approaches have provided fresh insight into the intrinsic factors determining the potency and duration of vaccine-induced immunity. The fundamental challenge will be to translate these findings into innovative and pragmatic strategies to develop new and more effective vaccines.

MHC class II and non-MHC class II genes differentially influence humoral immunity to Bacillus anthracis lethal factor and protective antigen

Anthrax Lethal Toxin consists of Protective Antigen (PA) and Lethal Factor (LF), and current vaccination strategies focus on eliciting antibodies to PA. In human vaccination, the response to PA can vary greatly, and the response is often directed toward non-neutralizing epitopes. Variable vaccine responses have been shown to be due in part to genetic differences in individuals, with both MHC class II and other genes playing roles. Here, we investigated the relative contribution of MHC class II versus non-MHC class II genes in the humoral response to PA and LF immunization using three immunized strains of inbred mice: A/J (H-2k at the MHC class II locus), B6 (H-2b), and B6.H2k (H-2k). IgG antibody titers to LF were controlled primarily by the MHC class II locus, whereas IgG titers to PA were strongly influenced by the non-MHC class II genetic background. Conversely, the humoral fine specificity of reactivity to LF appeared to be controlled primarily through non-MHC class II genes, while the specificity of reactivity to PA was more dependent on MHC class II. Common epitopes, reactive in all strains, occurred in both LF and PA responses. These results demonstrate that MHC class II differentially influences humoral immune responses to LF and PA.

Unraveling the effects of selection and demography on immune gene variation in free-ranging plains zebra (Equus quagga) populations

Demography, migration and natural selection are predominant processes affecting the distribution of genetic variation among natural populations. Many studies use neutral genetic markers to make inferences about population history. However, the investigation of functional coding loci, which directly reflect fitness, is critical to our understanding of species' ecology and evolution. Immune genes, such as those of the Major Histocompatibility Complex (MHC), play an important role in pathogen recognition and provide a potent model system for studying selection. We contrasted diversity patterns of neutral data with MHC loci, ELA-DRA and -DQA, in two southern African plains zebra (Equus quagga) populations: Etosha National Park, Namibia, and Kruger National Park, South Africa. Results from neutrality tests, along with observations of elevated diversity and low differentiation across populations, supported previous genus-level evidence for balancing selection at these loci. Despite being low, MHC divergence across populations was significant and may be attributed to drift effects typical of geographically separated populations experiencing little to no gene flow, or alternatively to shifting allele frequency distributions driven by spatially variable and fluctuating pathogen communities. At the DRA, zebra exhibited geographic differentiation concordant with microsatellites and reduced levels of diversity in Etosha due to highly skewed allele frequencies that could not be explained by demography, suggestive of spatially heterogeneous selection and local adaptation. This study highlights the complexity in which selection affects immune gene diversity and warrants the need for further research on the ecological mechanisms shaping patterns of adaptive variation among natural populations.

A genome-wide association study of host genetic determinants of the antibody response to Anthrax Vaccine Adsorbed

Several lines of evidence have supported a host genetic contribution to vaccine response, but genome-wide assessments for specific determinants have been sparse. Here we describe a genome-wide association study (GWAS) of protective antigen-specific antibody (AbPA) responses among 726 European-Americans who received Anthrax Vaccine Adsorbed (AVA) as part of a clinical trial. After quality control, 736,996 SNPs were tested for association with the AbPA response to 3 or 4 AVA vaccinations given over a 6-month period. No SNP achieved the threshold of genome-wide significance (p=5 × 10(-8)), but suggestive associations (p<1 × 10(-5)) were observed for SNPs in or near the class II region of the major histocompatibility complex (MHC), in the promoter region of SPSB1, and adjacent to MEX3C. Multivariable regression modeling suggested that much of the association signal within the MHC corresponded to previously identified HLA DR-DQ haplotypes involving component HLA-DRB1 alleles of *15:01, *01:01, or *01:02. We estimated the proportion of additive genetic variance explained by common SNP variation for the AbPA response after the 6 month vaccination. This analysis indicated a significant, albeit imprecisely estimated, contribution of variation tagged by common polymorphisms (p=0.032). Future studies will be required to replicate these findings in European Americans and to further elucidate the host genetic factors underlying variable immune response to AVA.

Proinflammatory HLA-DRB1*01-haplotype predisposes to ST-elevation myocardial infarction

BACKGROUND

Major histocompatibility complex (MHC) gene region harbours haplotypes that associate with coronary artery disease (CAD). Their role in ST-elevation infarction (STEMI) or on the inflammatory level is not known.

METHODS

Four candidate MHC markers were analyzed by real-time quantitative PCR and constructed into haplotypes from patients with STEMI (n = 162), matched controls with no CAD (n = 319) and general population sample (n = 149). High sensitivity C-reactive protein (hsCRP) was assessed in a follow-up visit from patients (n = 86) and at inclusion from other study subjects.

RESULTS

The haplotype with one copy of HLA-DRB1*01, C4A, C4B but no HLA-B*35 doubled the risk of STEMI (OR = 2.15, 95%CI = 1.11-4.15, p = 0.020 for patients vs. controls, and OR = 2.26, 95%CI = 0.97-5.24, p = 0.052 for patients vs. population sample). The association between patients and controls persisted in multivariate analyses. The frequency of the haplotype was 5.86% (n = 19/324) in patients, 2.82% (n = 18/638) in controls and 2.68% (n = 8/298) in population sample. None of the individual MHC markers alone showed significant association with STEMI. In multivariate analyses, the haplotype carriers had higher hsCRP levels in patients (median 3.37 mg/L in carriers vs. 1.14 mg/L in non-carriers, p = 0.019) and in controls (median 2.90 mg/L vs. 1.21 mg/L, p = 0.009, respectively).

CONCLUSION

The MHC haplotype associates with STEMI and elevated baseline hsCRP levels. The results are in concordance with previous data on non-STEMI patients, implying that a HLA-DRB1*01--related haplotype increases the risk of CAD, possibly though increased inflammation.