Immunologic significance of HLA class I genes in measles virus-specific IFN-gamma and IL-4 cytokine immune responses

Vaccinomics: A scoping review

BACKGROUND

This scoping review summarizes a key aspect of vaccinomics by collating known associations between heterogeneity in human genetics and vaccine immunogenicity and safety.

METHODS

We searched PubMed for articles in English using terms covering vaccines routinely recommended to the general US population, their effects, and genetics/genomics. Included studies were controlled and demonstrated statistically significant associations with vaccine immunogenicity or safety. Studies of Pandemrix®, an influenza vaccine previously used in Europe, were also included, due to its widely publicized genetically mediated association with narcolepsy.

FINDINGS

Of the 2,300 articles manually screened, 214 were included for data extraction. Six included articles examined genetic influences on vaccine safety; the rest examined vaccine immunogenicity. Hepatitis B vaccine immunogenicity was reported in 92 articles and associated with 277 genetic determinants across 117 genes. Thirty-three articles identified 291 genetic determinants across 118 genes associated with measles vaccine immunogenicity, 22 articles identified 311 genetic determinants across 110 genes associated with rubella vaccine immunogenicity, and 25 articles identified 48 genetic determinants across 34 genes associated with influenza vaccine immunogenicity. Other vaccines had fewer than 10 studies each identifying genetic determinants of their immunogenicity. Genetic associations were reported with 4 adverse events following influenza vaccination (narcolepsy, GBS, GCA/PMR, high temperature) and 2 adverse events following measles vaccination (fever, febrile seizure).

CONCLUSION

This scoping review identified numerous genetic associations with vaccine immunogenicity and several genetic associations with vaccine safety. Most associations were only reported in one study. This illustrates both the potential of and need for investment in vaccinomics. Current research in this field is focused on systems and genetic-based studies designed to identify risk signatures for serious vaccine reactions or diminished vaccine immunogenicity. Such research could bolster our ability to develop safer and more effective vaccines.

Prediction of Specific Antibody- and Cell-Mediated Responses Using Baseline Immune Status Parameters of Individuals Received Measles-Mumps-Rubella Vaccine

A successful vaccination implies the induction of effective specific immune responses. We intend to find biomarkers among various immune cell subpopulations, cytokines and antibodies that could be used to predict the levels of specific antibody- and cell-mediated responses after measles-mumps-rubella vaccination. We measured 59 baseline immune status parameters (frequencies of 42 immune cell subsets, levels of 13 cytokines, immunoglobulins) before vaccination and 13 response variables (specific IgA and IgG, antigen-induced IFN-γ production, CD107a expression on CD8+ T lymphocytes, and cellular proliferation levels by CFSE dilution) 6 weeks after vaccination for 19 individuals. Statistically significant Spearman correlations between some baseline parameters and response variables were found for each response variable (p < 0.05). Because of the low number of observations relative to the number of baseline parameters and missing data for some observations, we used three feature selection strategies to select potential predictors of the post-vaccination responses among baseline variables: (a) screening of the variables based on correlation analysis; (b) supervised screening based on the information of changes of baseline variables at day 7; and (c) implicit feature selection using regularization-based sparse regression. We identified optimal multivariate linear regression models for predicting the effectiveness of vaccination against measles-mumps-rubella using the baseline immune status parameters. It turned out that the sufficient number of predictor variables ranges from one to five, depending on the response variable of interest.

Mumps virus-specific immune response outcomes and sex-based differences in a cohort of healthy adolescents

Despite high levels of MMR-II usage in the US, mumps outbreaks continue to occur. Evidence suggests that mumps vaccine-induced humoral immunity wanes over time. Relatively few studies have examined cell-mediated immunity or reported on sex-based differences. To better understand sex-based differences in the immune response to mumps vaccine, we measured neutralizing antibody titers and mumps-specific cytokine/chemokine responses in a cohort of 748 adolescents and young adults after two doses of MMR vaccine. We observed significantly higher neutralizing antibody titers in females than in males (120.8 IU/mL, 98.7 IU/mL, p = 0.038) but significantly higher secretion levels of MIP-1α, MIP-1β, TNFα, IL-6, IFNγ, and IL-1β in males compared to females. These data demonstrate that sex influences mumps-specific humoral and cell-mediated immune response outcomes, a phenomenon that should be considered during efforts to improve vaccines and prevent future outbreaks.

Why do Individuals Differ in Viral Susceptibility? A Story Told by Model Organisms

Viral susceptibility and disease progression is determined by host genetic variation that underlies individual differences. Genetic polymorphisms that affect the phenotype upon infection have been well-studied for only a few viruses, such as HIV-1 and Hepatitis C virus. However, even for well-studied viruses the genetic basis of individual susceptibility differences remains elusive. Investigating the effect of causal polymorphisms in humans is complicated, because genetic methods to detect rare or small-effect polymorphisms are limited and genetic manipulation is not possible in human populations. Model organisms have proven a powerful experimental platform to identify and characterize polymorphisms that underlie natural variations in viral susceptibility using quantitative genetic tools. We summarize and compare the genetic tools available in three main model organisms, Mus musculus, Drosophila melanogaster, and Caenorhabditis elegans, and illustrate how these tools can be applied to detect polymorphisms that determine the viral susceptibility. Finally, we analyse how candidate polymorphisms from model organisms can be used to shed light on the underlying mechanism of individual variation. Insights in causal polymorphisms and mechanisms underlying individual differences in viral susceptibility in model organisms likely provide a better understanding in humans.

The effectiveness of measles-mumps-rubella (MMR) vaccination in the prevention of pediatric hospitalizations for targeted and untargeted infections: A retrospective cohort study

OBJECTIVES

To evaluate the effectiveness of the measles-mumps-rubella (MMR) vaccine in reducing hospitalizations for infectious disease, targeted and not targeted, as well as from respiratory diseases in children in Rome.

METHODS

The cohort was recomposed through record linkage of 2 archives (vaccination register and hospital discharge records.

RESULTS

The analysis included 11,004 children. 20.9% did not receive the MMR vaccination, 49% and 30.1% received one and 2 doses. There were no hospitalizations for rubella, 2 for mumps, and 12 for measles. The vaccine was highly protective against measles and mumps hospitalizations (HR = 0.10; 95% CI: 0.03.0.34). Regarding all infectious diseases there were 414 hospitalizations, and the vaccine was protective (HR = 0.29; 95% CI: 0.25 to 0.34). Concerning respiratory diseases, there were 809 admissions (7.4%), and the vaccine was highly protective (HR: 0.18; 95% CI: 0.07 to 0.48).

CONCLUSIONS

MMR vaccination is effective for the primary prevention of target and not targeted infectious diseases and may also limit hospitalizations for respiratory diseases.

A large population-based association study between HLA and KIR genotypes and measles vaccine antibody responses

Human antibody response to measles vaccine is highly variable in the population. Host genes contribute to inter-individual antibody response variation. The killer cell immunoglobulin-like receptors (KIR) are recognized to interact with HLA molecules and possibly influence humoral immune response to viral antigens. To expand on and improve our previous work with HLA genes, and to explore the genetic contribution of KIR genes to the inter-individual variability in measles vaccine-induced antibody responses, we performed a large population-based study in 2,506 healthy immunized subjects (ages 11 to 41 years) to identify HLA and KIR associations with measles vaccine-induced neutralizing antibodies. After correcting for the large number of statistical tests of allele effects on measles-specific neutralizing antibody titers, no statistically significant associations were found for either HLA or KIR loci. However, suggestive associations worthy of follow-up in other cohorts include B*57:01, DQB1*06:02, and DRB1*15:05 alleles. Specifically, the B*57:01 allele (1,040 mIU/mL; p = 0.0002) was suggestive of an association with lower measles antibody titer. In contrast, the DQB1*06:02 (1,349 mIU/mL; p = 0.0004) and DRB1*15:05 (2,547 mIU/mL; p = 0.0004) alleles were suggestive of an association with higher measles antibodies. Notably, the associations with KIR genotypes were strongly nonsignificant, suggesting that KIR loci in terms of copy number and haplotypes are not likely to play a major role in antibody response to measles vaccination. These findings refine our knowledge of the role of HLA and KIR alleles in measles vaccine-induced immunity.

HLA genotypes and rubella vaccine immune response: additional evidence

Recent population-based studies have demonstrated the genetic heritability of rubella vaccine response and assessed that the HLA system may explain about 20% of the inter-individual variance in humoral immune response to this vaccine. Our earlier studies compared HLA allelic associations with rubella vaccine-specific antibodies between two smaller cohorts of healthy Rochester, MN, children (346 and 396 subjects) after two doses of rubella-containing vaccine. This study found that specific HLA alleles were consistently associated with rubella-specific antibody titers (B*27:05, DPA1*02:01, and DPB1*04:01 alleles). The current study examined HLA associations in an independent larger cohort of 1012 healthy San Diego, CA, subjects (age 19-40 years) after rubella vaccine in order to replicate our previous findings in the Rochester subjects. Two HLA associations of comparable magnitudes were consistently observed between B*27:05 (median NT50 Rochester cohort 48.9, p=0.067; San Diego cohort 54.8, p=0.047) and DPB1*04:01 (median NT50 Rochester cohort 61.6, p<0.001; San Diego cohort 70.8, p=0.084) alleles and rubella virus-neutralizing antibody titers. Additional HLA alleles resulted in consistent effects on IL-6 production in both cohorts, but did not meet criteria for statistical significance. Our data suggest these HLA alleles play a role in rubella vaccine-induced immunity and provide the basis for future studies that may explain the mechanism(s) by which these HLA polymorphisms affect immune responses to rubella vaccine.

The genetic basis for interindividual immune response variation to measles vaccine: new understanding and new vaccine approaches

The live-attenuated measles vaccine is effective, but measles outbreaks still occur in vaccinated populations. This warrants elucidation of the determinants of measles vaccine-induced protective immunity. Interindividual variability in markers of measles vaccine-induced immunity, including neutralizing antibody levels, is regulated in part by host genetic factor variations. This review summarizes recent advances in our understanding of measles vaccine immunogenetics relative to the perspective of developing better measles vaccines. Important genetic regulators of measles vaccine-induced immunity, such as HLA class I and HLA class II genotypes, single nucleotide polymorphisms in cytokine/cytokine receptor genes (IL12B, IL12RB1, IL2, IL10) and the cell surface measles virus receptor CD46 gene, have been identified and independently replicated. New technologies present many opportunities for identification of novel genetic signatures and genetic architectures. These findings help explain a variety of immune response-related phenotypes and promote a new paradigm of 'vaccinomics' for novel vaccine development.

Associations between polymorphisms in the antiviral TRIM genes and measles vaccine immunity

The role of polymorphisms within the antiviral tripartite motif (TRIM) genes in measles vaccine adaptive immune responses was examined. A limited association was found between TRIM5 (rs7122620) and TRIM25 (rs205499) gene polymorphisms and measles-specific antibody levels. However, many associations were found between TRIM gene SNPs and variations in cellular responses (IFN-γ Elispot and secreted cytokines IL-2, IL-6, IL-10, IFN-γ, and TNF-α). TRIM22 rs2291841 was significantly associated with an increased IFN-γ Elispot response (35 vs. 102 SFC per 2×10(5)PBMC, p=0.009, q=0.71) in Caucasians. A non-synonymous TRIM25 rs205498 (in LD with other SNPs, r(2)≥0.56), as well as the TRIM25 AAAGGAAAGGAGT haplotype, was associated with a decreased IFN-γ Elispot response (t-statistic -2.32, p=0.02) in African-Americans. We also identified polymorphisms in the TRIM5, TRIM22, and TRIM25 genes that were associated with significant differences in cytokine responses. Additional studies are necessary to replicate our findings and to examine the functional consequences of these associations.

HLA-DR specific monoclonal antibodies block lymphoproliferative response to measles vaccine in vitro: a pilot study

Humoral and cell-mediated immune responses are important in protection against measles. Non-response to vaccination has been associated with specific HLA-DR and HLA-DQ alleles; however, little is known about the relative importance of these alleles in the cellular immune response induced by measles virus vaccine. To investigate the role of HLA-DR/DQ class II restriction, a small pilot study was conducted. Lymphoproliferation assays using class II DR and DQ-specific monoclonal antibodies (MoAb) were performed at one week and two weeks post immunization with MMRII vaccine. The mean stimulation index (SI) was 4.4 and 5.3 at one and two weeks with reductions in SI of 47.6% and 70.2%, respectively, following the addition of DR-specific MoAb (p<0.001). These results clearly show that a significant proportion of the cell-mediated immune response to measles virus vaccine, as measured by SI, is HLA-DR restricted.

HLA class II allele frequencies in the Lebanese population

AIMS

Being one of the most polymorphic genetic systems , the Human Leukocyte Antigen system is divided into class I (HLA-A, HLA-B and HLA-C) and class II (HLA-DP, -DQ and -DR). This study is the first and largest of its kind to describe the distribution of HLA-DQB1 and HLA-DRB1 alleles in Lebanon and the region.

METHODS

Respectively, 560 and 563 Lebanese individuals referred for HLA typing and possible bone marrow/kidney donation were tested for HLA-DQB1 and HLA-DRB1 alleles using the polymerase chain reaction/sequence specific priming (PCR-SSP) method.

RESULTS

Our data were compared to that of several populations with interesting common findings between the Lebanese, Jordanian, Bahraini, Saudi, Kuwaiti, Tunisian, Korean, Japanese, Thai, Irish, Bulgarian and Polish populations.

CONCLUSION

These data about the Lebanese population are going to aid future researchers to study the relation of HLA-DQB1 and HLA-DRB1 alleles with major and common diseases in the Lebanese population and will add to the available international literature associated with these loci. In addition it will serve as a reference for the future national bone marrow registry program in our country. We also reviewed the literature for the described association between HLA-DRB1 and -DQB1 loci and different disease entities.

Associations between demographic variables and multiple measles-specific innate and cell-mediated immune responses after measles vaccination

Measles remains a public health concern due to a lack of vaccine use and vaccine failure. A better understanding of the factors that influence variations in immune responses, including innate/inflammatory and adaptive cellular immune responses, following measles-mumps-rubella (MMR) vaccination could increase our knowledge of measles vaccine-induced immunity and potentially lead to better vaccines. Measles-specific innate/inflammatory and adaptive cell-mediated immune (CMI) responses were characterized using enzyme-linked immunosorbent assays to quantify the levels of secreted IL-2, IL-6, IL-10, IFN-α, IFN-γ, IFN-λ1, and TNF-α in PBMC cultures following in vitro stimulation with measles virus (MV) in a cohort of 764 school-aged children. IFN-γ ELISPOT assays were performed to ascertain the number of measles-specific IFN-γ-secreting cells. Cytokine responses were then tested for associations with self-declared demographic data, including gender, race, and ethnicity. Females secreted significantly more TNF-α, IL-6, and IFN-α (p<0.001, p<0.002, p<0.04, respectively) compared to males. Caucasians secreted significantly more IFN-λ1, IL-10, IL-2, TNF-α, IL-6, and IFN-α (p<0.001, p<0.001, p<0.001, p<0.003, p<0.01, and p<0.02, respectively) compared to the other racial groups combined. Additionally, Caucasians had a greater number of IFN-γ-secreting cells compared to other racial groups (p<0.001). Ethnicity was not significantly correlated with variations in measles-specific CMI measures. Our data suggest that innate/inflammatory and CMI cytokine responses to measles vaccine vary significantly by gender and race. These data further advance our understanding regarding inter-individual and subgroup variations in immune responses to measles vaccination.

Consistency of HLA associations between two independent measles vaccine cohorts: a replication study

Associations between HLA genotypes and measles vaccine humoral and cellular immune responses were examined to better understand immunogenetic drivers of vaccine response. Two independent study cohorts of healthy schoolchildren were examined: cohort one, 346 children between 12 and 18 years of age; and cohort two, 388 children between 11 and 19 years of age. All received two age-appropriate doses of measles-containing vaccine. The purpose of this study was to identify and replicate associations between HLA genes and immune responses following measles vaccination found in our first cohort. Associations of comparable magnitudes and with similar p-values were observed between B*3503 (1st cohort p=0.01; 2nd cohort p=0.07), DQA1*0201 (1st cohort p=0.03; 2nd cohort p=0.03), DQB1*0303 (1st cohort p=0.10; 2 cohort p=0.02), DQB1*0602 (1st cohort p=0.07; 2nd cohort p=0.10), and DRB1*0701 (1st cohort p=0.03; 2nd cohort p=0.07) alleles and measles-specific antibody levels. Suggestive, yet consistent, associations were observed between the B7 (1st cohort p=0.01; 2nd cohort p=0.08) supertype and higher measles antibody levels in both cohorts. Also, in both cohorts, the B*0801 and DRB1*0301 alleles, C*0802 and DPA1*0202 alleles, and DRB1*1303 alleles displayed consistent associations with variations in IFN-γ, IL-2 and IL-10 secretion, respectively. This study emphasizes the importance of replicating HLA associations with measles vaccine-induced humoral and cellular immune responses and increases confidence in the results. These data will inform strategies for functional studies and novel vaccine development, including epitope-based measles vaccines. This is the first HLA association replication study with measles vaccine-specific immune responses to date.

Multigenic control of measles vaccine immunity mediated by polymorphisms in measles receptor, innate pathway, and cytokine genes

Measles infection and vaccine response are complex biological processes that involve both viral and host genetic factors. We have previously investigated the influence of genetic polymorphisms on vaccine immune response, including measles vaccines, and have shown that polymorphisms in HLA, cytokine, cytokine receptor, and innate immune response genes are associated with variation in vaccine response but do not account for all of the inter-individual variance seen in vaccinated populations. In the current study we report the findings of a multigenic analysis of measles vaccine immunity, indicating a role for the measles virus receptor CD46, innate pattern-recognition receptors (DDX58, TLR2, 4, 5, 7 and 8) and intracellular signaling intermediates (MAP3K7, NFKBIA), and key antiviral molecules (VISA, OAS2, MX1, PKR) as well as cytokines (IFNA1, IL4, IL6, IL8, IL12B) and cytokine receptor genes (IL2RB, IL6R, IL8RA) in the genetic control of both humoral and cellular immune responses. This multivariate approach provided additional insights into the genetic control of measles vaccine responses over and above the information gained by our previous univariate SNP association analyses.

Vaccinomics and a new paradigm for the development of preventive vaccines against viral infections

In this article we define vaccinomics as the integration of immunogenetics and immunogenomics with systems biology and immune profiling. Vaccinomics is based on the use of cutting edge, high-dimensional (so called "omics") assays and novel bioinformatics approaches to the development of next-generation vaccines and the expansion of our capabilities in individualized medicine. Vaccinomics will allow us to move beyond the empiric "isolate, inactivate, and inject" approach characterizing past vaccine development efforts, and toward a more detailed molecular and systemic understanding of the carefully choreographed series of biological processes involved in developing viral vaccine-induced "immunity." This enhanced understanding will then be applied to overcome the obstacles to the creation of effective vaccines to protect against pathogens, particularly hypervariable viruses, with the greatest current impact on public health. Here we provide an overview of how vaccinomics will inform vaccine science, the development of new vaccines and/or clinically relevant biomarkers or surrogates of protection, vaccine response heterogeneity, and our understanding of immunosenescence.

Human leukocyte antigen associations with humoral and cellular immunity following a second dose of measles-containing vaccine: persistence, dampening, and extinction of associations found after a first dose

Previously we found human leukocyte antigen (HLA) associations with humoral immunity following a single dose of measles-containing vaccine. In this study, we sought to determine if HLA associations exist with humoral and cellular immunity following a second dose of measles-containing vaccine and if the associations we found with humoral immunity after the first dose persist following a second dose. We recruited a population-based sample of 346 schoolchildren, all who previously received two doses of a measles-containing vaccine. Molecular HLA classes I and II typing as well as humoral and cellular immune assays (measles-specific IgG antibody levels and lymphoproliferative response) were performed in these subjects. We found significant associations with class I HLA-B (p=0.05) as well as class II HLA-DPB1 (p=0.01) and -DPA1 (p=0.03) genes for measles vaccine-induced antibody levels after the second dose. Similarly, we found significant associations with class II HLA-DQB1 (p=0.05) and -DRB1 (p=0.01) genes for measles-specific lymphoproliferation after the second dose. While we found HLA associations after the second dose that we previously found after the first dose of measles containing vaccine, fewer alleles had statistically significant associations, suggesting that the second dose had a dampening or extinguishing effect on the HLA associations. It appears that the second dose overcomes HLA restriction through an as yet unknown mechanism. Future studies of HLA associations should consider both the effect of dose and the role that subsequent doses might play on genetic associations found with the response to a first dose.

Human leukocyte antigen genotypes in the genetic control of adaptive immune responses to smallpox vaccine

BACKGROUND

The role of human leukocyte antigen (HLA) genes in mediating adaptive immune responses to smallpox vaccine remains unknown.

METHODS

We determined genotypes for a group of individuals (n = 1071) who received a single dose of smallpox vaccine (Dryvax, Wyeth Laboratories) and examined associations between HLA alleles and 15 immune outcomes to smallpox vaccine on a per-locus and a per-allele level.

RESULTS

We found significant associations between the HLA-B and HLA - DQB1 loci and vaccinia-induced antibodies (P = .04 for each locus), with the HLA-B*1302 (P = .036), B*3802 (P = .011), DQB1*0302 (P = .015), and DQB1*0604 (P = .017) alleles being associated with higher levels. Significant global associations were identified between vaccinia-specific interferon (IFN)-γ and DQA1 (P = .003), interleukin (IL)-1β and HLA-B (P = .004), tumor necrosis factor (TNF)-α and HLA-B (P = .006), and IL-6 and HLA-B locus (P = .016) for secreted cytokines, as well as between CD8α(+) IFN-γ Elispot responses and DQB1 (P = .027). Subjects carrying B*3906 (P = .006) and B*5701 (P < .001) secreted higher levels of IL-1β than did subjects who did not carry these alleles. Subjects carrying the B*5301 (P = .047) and B*5601 (P = .008) alleles secreted less IL-1β, compared with subjects who did not carry these alleles. The B*3502 (P = .009), B*5601 (P = .004), and B*5701 (P < .001) alleles were significantly associated with variations in TNF-α secretion.

CONCLUSIONS

These data suggest that variations in antibody and cellular IFN-γ, IL-1β, TNF-α, and IL-6 immune responses after receipt of smallpox vaccine are genetically controlled by HLA genes or genes in close linkage disequilibrium to these alleles.

Differential cellular immune responses to wild-type and attenuated edmonston tag measles virus strains are primarily defined by the viral phosphoprotein gene

The measles virus phosphoprotein (P) gene encodes the P, V, and C proteins, which have multiple functions including type I interferon (IFN) inhibition. With a focus on viral immune modulation, we conducted a study on healthy vaccinees (n=179) to compare cytokine secretion patterns/cell frequencies and gene expression after in vitro encounter with a highly attenuated strain of measles virus (MVEdmtag), wild-type MV (MVwt) or recombinant MVEdmtag expressing the wild-type P gene (MVwtP). Cytokines were quantified by ELISA and Elispot. Gene expression profiling was performed using real-time PCR. We found differential MV-specific cytokine responses to all detected cytokines characterized by significantly higher cytokine levels (P<0.001) and higher frequencies (P<0.0001) of cytokine-producing cells after stimulation with the highly attenuated MVEdmtag strain in comparison with MVwt or MVwtP. Furthermore, gene expression profiling revealed significant cytokine suppression at the transcriptional level for viruses encoding the functional wt P gene, compared to attenuated MVEdmtag (P<0.05). Using lentivirus-mediated stable expression of P gene-encoded proteins in human cell lines, we demonstrated that the expression of the functional wt V protein significantly down-modulated the induction of IFNs type I, II, and III in lymphocytes and monocytes. Taken together our results indicate that Th1, Th2, and innate/inflammatory cytokine responses in vaccinees are suppressed both at the protein and transcriptional level by viruses expressing the functional wt P gene products. The functional P gene-encoded viral proteins (particularly V proteins) emerge as crucial immune evasion factors for modulating and shaping the measles virus-specific cytokine responses in humans.

Optimizing high dimensional gene expression studies for immune response following smallpox vaccination using Taqman® low density immune arrays

INTRODUCTION

We sought to determine the time and vaccinia virus dose combination that would maximize the number of acute immune response changes in response to vaccinia stimulation in preparation for a large gene expression microarray experiment.

METHODS

PBMCs from ten subjects were exposed to five vaccinia virus doses for three lengths of time. Gene expression was measured for 90 immune response genes via Taqman® Low Density Immune Arrays. Expression data were normalized via model-based non-linear normalization. Linear mixed effects model results were used to standardize changes across genes and determine the time/multiplicity of infection (MOI) combination with the largest number of changes.

RESULTS

The greatest number of changes occurred with a MOI of 5.0 and exposure time of 48 h. Further inspection revealed that most changes had occurred earlier and faded at this combination. The second highest number of changes was found at a MOI of 0.5 PFU/cell and time of 18 h.

CONCLUSIONS

We conclude a time of 18 h with a MOI of 0.5 PFU/cell is the optimal time/MOI combination for the full scale gene expression study. The strategy described herein is a general and resource efficient way to make critical decisions regarding experimental parameters for studies utilizing expensive assays that interrogate a large number of variables.

Antibodies to measles in individuals with recent onset psychosis

BACKGROUND

Measles virus is a highly prevalent neurotropic virus capable of causing persistent infections within the central nervous system.

METHODS

We measured IgG class antibodies to measles in 820 individuals including 138 with recent onset psychosis, 378 with persistent schizophrenia, and 304 non-psychiatric controls. Levels of antibodies among the groups were compared by bivariate and by multivariate analyses and correlated with clinical and demographic variables.

RESULTS

The level of measles antibodies in individuals with a recent onset of psychosis was greater than the level of antibodies in individuals with persistent schizophrenia or individuals without a history of a psychiatric disorder (p<.00001). The level of measles antibodies in the individuals with persistent schizophrenia was greater than the level of measles antibodies in the controls (p<.001). Recent onset of psychosis was associated with having elevated levels of measles antibodies, defined as the 90th percentile of the levels of the controls, with an odds ratio of 8.0 (95% CI 4.6, 14.0); persistent schizophrenia was associated with having this level with an odds ratio of 2.3 (95% CI 1.4, 3.7). Within the psychiatric groups, measles antibody levels were associated with age, race, and current treatment with the antipsychotic medication, olanzapine.

CONCLUSIONS

The reasons for elevated levels of measles antibodies in the psychiatric groups are not known with certainty and should be studied in prospective investigations.

Predominant inflammatory cytokine secretion pattern in response to two doses of live rubella vaccine in healthy vaccinees

We conducted a population-based study on 738 schoolchildren who received two doses of rubella vaccine in order to determine cytokine secretion patterns and their associations with demographic and clinical variables. The results showed a robust rubella-specific inflammatory cytokine response characterized by high median [inter-quartile range (IQR)] secretion levels (in pg/mL) of IL-6 [3681.0 (3160.0, 4052.0)], GM-CSF [28.0 (23.6, 32.6)], and TNF-alpha [29.7 (-7.0, 89.2)]. We also detected modest levels of rubella-specific secretion of Th1 cytokines IL-2 and IFN-gamma, while IL-12p40 was undetectable. In contrast, rubella-specific Th2 responses were hardly detectable. Age at vaccination, enrollment, and time elapsed between last vaccination and enrollment was significantly associated with the outcome of IL-2, IL-6, and IFN-gamma secretion. These results suggest an immune-deviation or "skewing" from Th1/Th2 cytokine patterns towards a predominant inflammatory response upon in vitro rubella virus stimulation.

Interindividual variations in the efficacy and toxicity of vaccines

A number of currently available vaccines have shown significant differences in the magnitude of immune responses and toxicity in individuals undergoing vaccination. A number of factors may be involved in the variations in immune responses, which include age, gender, race, amount and quality of the antigen, the dose administered and to some extent the route of administration, and genetics of immune system. Hence, it becomes imperative that researchers have tools such as genomics and proteomics at their disposal to predict which set of population is more likely to be non-responsive or develop toxicity to vaccines. In this article, we briefly review the influence of pharmacogenomics biomarkers on the efficacy and toxicity of some of the most frequently reported vaccines that showed a high rate of variability in response and toxicity towards hepatitis B, measles, mumps, rubella, influenza, and AIDS/HIV.

Application of pharmacogenomics to vaccines

The field of pharmacogenomics and pharmacogenetics provides a promising science base for vaccine research and development. A broad range of phenotype/genotype data combined with high-throughput genetic sequencing and bioinformatics are increasingly being integrated into this emerging field of vaccinomics. This paper discusses the hypothesis of the 'immune response gene network' and genetic (and bioinformatic) strategies to study associations between immune response gene polymorphisms and variations in humoral and cellular immune responses to prophylactic viral vaccines, such as measles-mumps-rubella, influenza, HIV, hepatitis B and smallpox. Immunogenetic studies reveal promising new vaccine targets by providing a better understanding of the mechanisms by which gene polymorphisms may influence innate and adaptive immune responses to vaccines, including vaccine failure and vaccine-associated adverse events. Additional benefits from vaccinomic studies include the development of personalized vaccines, the development of novel vaccines and the development of novel vaccine adjuvants.

Cytokine imbalance after measles virus infection has no correlation with immune suppression

Measles virus infection leads to immune suppression. A potential mechanism is the reduction of interleukin 12 (IL-12) secretion during acute measles, resulting in a TH2 response. Studies in humans have reported conflicting results, detecting either a TH2 or a TH1 response. We have investigated the correlation between a TH2 response and immune suppression in specific-pathogen-free inbred cotton rats which were infected with measles vaccine and wild-type viruses. After infection of bone marrow-derived macrophages with wild-type virus, IL-12 secretion was reduced in contrast to the level for vaccine virus infection. In bronchoalveolar lavage cells, IL-12 secretion was suppressed after infection with both wild-type and vaccine virus on days 2, 4, and 6 and was detectable on days 8 and 10. After stimulation of mediastinal lymph node and spleen cells with UV-inactivated measles virus at various time points after infection, gamma interferon but no IL-4 was found. After stimulation with phorbol myristate acetate-ionomycin, high gamma interferon and low IL-4 levels were detected. To investigate whether the secretion of IL-4 contributes to immune suppression, a recombinant vaccine virus was created which secretes cotton rat IL-4. After infection with this recombinant virus, IL-4 secretion was enhanced. However, neither inhibition of concanavalin A-stimulated spleen cells nor keyhole limpet hemocyanin-specific proliferation of spleen cells was altered after infection with the recombinant virus in comparison to the levels with the parental virus. Our data indicate that measles virus infection leads to a decrease in IL-12 secretion and an increase in IL-4 secretion, but this does not seem to correlate with immune suppression.

Major histocompatibility complex haplotype determines hsp70-dependent protection against measles virus neurovirulence

In vitro studies show that hsp70 promotes gene expression for multiple viral families, although there are few reports on the in vivo significance of virus-hsp70 interaction. Previously we showed that hsp70-dependent stimulation of Edmonston measles virus (Ed MeV) transcription caused an increased cytopathic effect and mortality in transgenic hsp70-overexpressing C57BL/6 mice (H-2(b)). The response to MeV infection is influenced by the major histocompatibility complex haplotype; H-2(d) mice are resistant to brain infection due to robust antiviral immune responses, whereas H-2(b) mice are susceptible due to deficiencies in this response. We therefore tested the hypothesis that the outcome of MeV-hsp70 interaction may be dependent upon the host H-2 haplotype. The impact of selective neuronal hsp70 overexpression on Ed MeV brain infection was tested with congenic C57BL/10 H-2(d) neonatal mice. In this context, hsp70 overexpression conferred complete protection against virus-induced mortality, compared to >30% mortality in nontransgenic mice. Selective depletion of T-cell populations showed that transgenic mice exhibit a diminished reliance on T cells for protection. Brain transcript analysis indicated enhanced innate immune activation and signaling through Toll-like receptors 2 and 4 at early times postinfection for transgenic infected mice relative to those for nontransgenic infected mice. Collectively, results suggest that hsp70 can enhance innate antiviral immunity through Toll-like receptor signaling, supporting a protective role for physiological responses that enhance tissue levels of hsp70 (e.g., fever), and that the H-2 haplotype determines the effectiveness of this response.

Influence of host genetic variation on rubella-specific T cell cytokine responses following rubella vaccination

The variability of immune response modulated by immune response gene polymorphisms is a significant factor in the protective effect of vaccines. We studied the association between cellular (cytokine) immunity and HLA genes among 738 schoolchildren (396 males and 342 females) between the ages of 11 and 19 years, who received two doses of rubella vaccine (Merck). Cytokine secretion levels in response to rubella virus stimulation were determined in PBMC cultures by ELISA. Cell supernatants were assayed for Th1 (IFN-gamma, IL-2, and IL-12p40), Th2 (IL-4, IL-5, and IL-10), and innate/proinflammatory (TNF-alpha, GM-CSF, and IL-6) cytokines. We found a strong association between multiple alleles of the HLA-DQA1 (global p-value 0.022) and HLA-DQB1 (global p-value 0.007) loci and variations in rubella-specific IL-2 cytokine secretion. Additionally, the relationships between alleles of the HLA-A (global p-value 0.058), HLA-B (global p-value 0.035), and HLA-C (global p-value 0.023) loci and TNF-alpha secretion suggest the importance of HLA class I molecules in innate/inflammatory immune response. Better characterization of these genetic profiles could help to predict immune responses at the individual and population level, provide data on mechanisms of immune response development, and further inform vaccine development and vaccination policies.

Response surface methodology to determine optimal cytokine responses in human peripheral blood mononuclear cells after smallpox vaccination

Feasibility, amount of sample aliquots, processing time and cost are critical considerations for optimizing and conducting assays for large-population based studies. Well designed statistical approaches that quickly identify optimal conditions for a given assay could assist efficient completion of the laboratory assays for such studies. For example, assessment of the profile of secreted cytokines is important in understanding the immune response after vaccination. To characterize the cytokine immune response following smallpox vaccination, PBMC obtained from recently vaccinated subjects were stimulated with varying doses of live or UV-inactivated vaccinia virus and cultured for up to 8 days. In this paper, we describe a novel statistical method to identify optimal operating conditions for length in culture and virus MOI in order to measure a panel of secreted Th1, Th2, and inflammatory cytokines. This statistical method is comprised of two components. It first identifies a subset of the possible time in culture by virus MOI combinations to be studied. It then utilizes response surface analysis techniques to predict the optimal operating conditions for the measurement of each secreted cytokine. This method was applied, and the predicted optimal combinations of length in culture and virus MOI for maximum vaccinia-specific cytokine secretion were identified. The use of the response surface methodology can be applied to the optimization of other laboratory assays; especially when the number of PBMC available limits the testing of all possible combinations of parameters.

Vaccine immunogenetics: bedside to bench to population

The immunogenetic basis for variations in immune response to vaccines in humans remains largely unknown. Many factors can contribute to the heterogeneity of vaccine-induced immune responses, including polymorphisms of immune response genes. It is important to identify those genes involved directly or indirectly in the generation of the immune response to vaccines. Our previous work with measles reveals the impact of immune response gene polymorphisms on measles vaccine-induced humoral and cellular immune responses. We demonstrate associations between genetic variations (single nucleotide polymorphisms, SNPs) in HLA class I and class II genes, cytokine, cell surface receptor, and toll-like receptor genes and variations in immune responses to measles vaccine. Such information may provide further understanding of genetic restrictions that influence the generation of protective immune responses to vaccines, and eventually the development of new vaccines.

Genetic studies of African populations: an overview on disease susceptibility and response to vaccines and therapeutics

Africa is the ultimate source of modern humans and as such harbors more genetic variation than any other continent. For this reason, studies of the patterns of genetic variation in African populations are crucial to understanding how genes affect phenotypic variation, including disease predisposition. In addition, the patterns of extant genetic variation in Africa are important for understanding how genetic variation affects infectious diseases that are a major problem in Africa, such as malaria, tuberculosis, schistosomiasis, and HIV/AIDS. Therefore, elucidating the role that genetic susceptibility to infectious diseases plays is critical to improving the health of people in Africa. It is also of note that recent and ongoing social and cultural changes in sub-Saharan Africa have increased the prevalence of non-communicable diseases that will also require genetic analyses to improve disease prevention and treatment. In this review we give special attention to many of the past and ongoing studies, emphasizing those in Sub-Saharan Africans that address the role of genetic variation in human disease.

[Tumor inhibiting and immunoloregulation effects of Mylabris Mixture on H22 cancer-bearing mice]

OBJECTIVE

To investigate the mechanisms of tumor inhibiting and immunoloregulation of Mylabris Mixture on H22 cancer-bearing mice.

METHODS

H22 cancer-bearing mice were chosen to observe the effects of tumor inhibiting and detect the proliferation function of T lymphocytes, the toxicity function of NK cells, the changes of T lymphocytes and the contents of interferon-gamma and interleukin-4.

RESULTS

Mylabris Mixture could obviously inhibit the growth of H22 cancer in mice, and the tumor inhibition rat was 65.76%. The stimulation index of T lymphocyte transformation and percentage of NK cells in Mylabris Mixture-treated group were obviously higher than those in the normal control group. The subpopulation proportion of T lymphocytes in Mylabris Mixture-treated group was changed more than the normal control group. The production of interferon-gamma and interleukin-4 by T lymphocytes obviously increased in Mylabris Mixture-treated group (P<0.05, P<0.001).

CONCLUSION

Mylabris Mixture has the effect of inhibiting the growth of tumor constitution, and regulating immunological function on mice with tumor. Its mechanisms include the reinforcement of T lymphocyte immune function, NK cell killing function and humoral immune function.

Genetic variation in the response to vaccination

Vaccines are the most powerful means to prevent and diminish the burden of infectious disease. However, there are limitations to their use: vaccines are not yet available for all infectious diseases (including human immunodeficiency virus and respiratory syncytial virus), they sometimes lack efficacy, the response to vaccination is limited by maternal antibodies in very young infants, and the response to vaccination is variable or may even be absent in some individuals. This review focuses on genetic factors that determine the variable response to vaccination. The highly polymorphic human leukocyte antigen system, which is involved in antigen presentation, has been researched most in this aspect, and clearly affects the response to vaccination. Other, but less polymorphic pathways involved are the Toll-like receptor pathway, which is involved in antigen recognition and stimulation of the immune system, and the cytokine immunoregulatory network. The heritability, or the proportion of total variance that is due to additive genetic factors, appears to be particularly large for vaccine-induced antibody responses in young infants compared with cell-mediated responses and antibody responses in older, immunologically more mature individuals. Both antibody and cell-mediated responses are not only affected by loci within, but also strongly by loci outside the human leukocyte antigen system. Because most genes that are important in influencing immune responses to vaccination are still unknown, clearly more work is required. A better understanding of the factors that determine an effective response to vaccination may lead to the identification of specific genes and pathways as targets for the development of novel more uniformly effective vaccines.

Heterogeneity in vaccine immune response: the role of immunogenetics and the emerging field of vaccinomics

Recent advances in the fields of immunology, genetics, molecular biology, bioinformatics, and the Human Genome Project have allowed for the emergence of the field of vaccinomics. Vaccinomics encompasses the fields of immunogenetics and immunogenomics as applied to understanding the mechanisms of heterogeneity in immune responses to vaccines. In this study, we examine the role of HLA genes, cytokine genes, and cell surface receptor genes as examples of how genetic polymorphism leads to individual and population variations in immune responses to vaccines. In turn, this data, in concert with new high-throughput technology, inform the immune-response network theory to vaccine response. Such information can be used in the directed and rational development of new vaccines, and this new golden age of vaccinology has been termed "predictive vaccinology", which will predict the likelihood of a vaccine response or an adverse response to a vaccine, the number of doses needed and even whether a vaccine is likely to be of benefit (i.e., is the individual at risk for the outcome for which the vaccine is being administered?).

Human leukocyte antigen and interleukin 2, 10 and 12p40 cytokine responses to measles: is there evidence of the HLA effect?

HLA class I and class II associations were examined in relation to measles virus-specific cytokine responses in 339 healthy children who had received two doses of live attenuated measles vaccine. Multivariate linear regression modeling analysis revealed suggestions of associations between the expression of DPA1*0201 (p=0.03) and DPA1*0202 (p=0.09) alleles and interleukin-2 (IL-2) cytokine production (global p-value 0.06). Importantly, cytokine production and DQB1 allele associations (global p-value 0.04) revealed that the alleles with the strongest association with IL-10 secretion were DQB1*0302 (p=0.02), DQB1*0303 (p=0.07) and DQB1*0502 (p=0.06). Measles-specific IL-10 secretion associations approached significance with DRB1 and DQA1 loci (both global p-values 0.08). Specifically, suggestive associations were found between DRB1*0701 (p=0.07), DRB1*1103 (p=0.06), DRB1*1302 (p=0.08), DRB1*1303 (p=0.06), DQA1*0101 (p=0.08), and DQA1*0201 (p=0.04) alleles and measles-induced IL-10 secretion. Further, suggestive association was observed between specific DQA1*0505 (p=0.002) alleles and measles-specific IL-12p40 secretion (global p-value 0.09) indicating that cytokine responses to measles antigens are predominantly influenced by HLA class II genes. We found no associations between any of the alleles of HLA A, B, and Cw loci and cytokine secretion. These novel findings suggest that HLA class II genes may influence the level of cytokine production in the adaptive immune responses to measles vaccine.