SLAM and DC-SIGN measles receptor polymorphisms and their impact on antibody and cytokine responses to measles vaccine

Genetics and measles, mumps and rubella vaccine response in childhood and adolescence-A systematic review

Measles, mumps and rubella (MMR) are contagious infectious diseases that can be prevented by immunization. However, MMR infections can occur in previously immunized individuals. The vaccine response is, among other factors, influenced by the combined effects of many genes. This systematic review investigates the genetic influence on measles, mumps and rubella antibody responses after childhood vaccination. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), systematic literature searches were conducted in the medical databases PubMed, EMBASE and PsycINFO. Search strings were adjusted for each database. Citations were included if they measured and compared the immune response with immunogenetics after vaccination with a vaccine containing one or more of the following components: measles, mumps and/or rubella, MMR. The measure of vaccine response studied was antibodies after vaccination. Forty-eight articles were included in the final analysis. The results suggest that genetic determinants, including host genes, and single nucleotide polymorphisms in immune-related genes influence the MMR antibody responses after vaccination. Specifically, replicated associations were found between HLA, CD46, RARB, IRF9, EIF2AK2, cytokine genes and MMR vaccine-induced humoral immune responses. This knowledge can be useful in understanding and predicting immune responses and may have implications for future vaccine strategies.

Association of single nucleotide polymorphisms in the CD209, MMP9, TNFA and IFNG genes with susceptibility to Japanese encephalitis in children from North India

Japanese encephalitis (JE), an acute encephalitis syndrome disease caused by infection with JE virus (JEV), is an important mosquito borne disease in developing countries. The clinical outcomes of JEV infection show inter individual differences. Only in a minor percent of the infected subjects, the disease progresses into acute encephalitis syndrome. Single nucleotide polymorphisms in the host immune response related genes are known to affect susceptibility to JE. In the present study, 238 JE cases and 405 healthy controls (HCs) without any known history of encephalitis were investigated for SNPs in the CD209 MX1, TLR3, MMP9, TNFA and IFNG genes which are important in the immune response against JEV by PCR based methods. The results revealed higher frequencies of heterozygous genotypes of CD209 rs4804803, MMP9 rs17576, TNFA rs1800629 and IFNG rs2430561 in JE cases compared to HCs. These SNPs were associated with JE in an over-dominant genetic model (Odds ratio with 95% CI 1.51 (1.09-2.10) for CD209 rs4804803, 1.52 (1.09-2.11) for MMP9 rs17576, and 1.55 (1.12-2.15) for IFNG rs2430561). The association of G/A genotype of TNFA rs1800629 with JE was confirmed in a larger sample size. The results suggest the association of CD209 rs4804803, MMP9 rs17576, IFNG rs2430561 and TNFA rs1800629 polymorphisms with susceptibility to JE.

Genetic associations with a fever after measles-containing vaccines

Children have elevated fever risk 1 to 2 weeks after the first dose of a measles-containing vaccine (MCV), which is likely affected by genetic, immunologic, and clinical factors. Fever after MCV is associated with febrile seizures, though may also be associated with higher measles antibody titers. This exploratory study investigated genetic and immunologic associations with a fever after MCV. Concurrent with a randomized Phase 3 clinical trial of 12–15-month-olds who received their first measles-mumps-rubella (MMR) vaccine in which parents recorded post-vaccination temperatures daily, we consented a subset to collect additional blood and performed human leukocyte antigens (HLA) typing. Association between fever 5–12 days after MMR (“MMR-associated”) and HLA type was assessed using logistic regression. We compared 42-day post-vaccination geometric mean titers (GMT) to measles between children who did and did not have fever using a t-test. We enrolled 86 children and performed HLA typing on 82; 13 (15.1%) had MMR-associated fever. Logistic regressions identified associations between MMR-associated fever and HLA Class I loci A-29:02 (P = .036), B-57:01 (P = .018), C-06:02 (P = .006), C-14:02 (P = .022), and Class II loci DRB1-15 (P = .045). However, Bonferroni's adjustment for multiple comparisons suggests that these associations could have been due to chance. Ninety-eight percent of children had protective antibody titers to measles; however, GMT was higher among those with fever compared with children without fever (P = .006). Fever after the measles vaccine correlated with genetic factors and higher immune response. This study suggests a possible genetic susceptibility to MMR-associated fever.

Investigating the Interaction between Negative Strand RNA Viruses and Their Hosts for Enhanced Vaccine Development and Production

The current pandemic has highlighted the ever-increasing risk of human to human spread of zoonotic pathogens. A number of medically-relevant zoonotic pathogens are negative-strand RNA viruses (NSVs). NSVs are derived from different virus families. Examples like Ebola are known for causing severe symptoms and high mortality rates. Some, like influenza, are known for their ease of person-to-person transmission and lack of pre-existing immunity, enabling rapid spread across many countries around the globe. Containment of outbreaks of NSVs can be difficult owing to their unpredictability and the absence of effective control measures, such as vaccines and antiviral therapeutics. In addition, there remains a lack of essential knowledge of the host–pathogen response that are induced by NSVs, particularly of the immune responses that provide protection. Vaccines are the most effective method for preventing infectious diseases. In fact, in the event of a pandemic, appropriate vaccine design and speed of vaccine supply is the most critical factor in protecting the population, as vaccination is the only sustainable defense. Vaccines need to be safe, efficient, and cost-effective, which is influenced by our understanding of the host–pathogen interface. Additionally, some of the major challenges of vaccines are the establishment of a long-lasting immunity offering cross protection to emerging strains. Although many NSVs are controlled through immunisations, for some, vaccine design has failed or efficacy has proven unreliable. The key behind designing a successful vaccine is understanding the host–pathogen interaction and the host immune response towards NSVs. In this paper, we review the recent research in vaccine design against NSVs and explore the immune responses induced by these viruses. The generation of a robust and integrated approach to development capability and vaccine manufacture can collaboratively support the management of outbreaking NSV disease health risks.

Parental risk factors for fever in their children 7-10 days after the first dose of measles-containing vaccines

We evaluated whether parental clinical conditions were associated with fever after a first dose of measles-containing vaccine (MCV) in the child in a cohort study including 244,125 children born in Kaiser Permanente Northern California between 2009 and 2016 who received MCV between ages 1 and 2 years. Each child was linked with his/her mother and father when possible. Parental clinical conditions present before and after their child’s birth were identified. We defined fever in the children as clinic and emergency department visits with a fever code 7–10 days after a first dose of MCV (“MCV-associated fever”). We evaluated parental clinical conditions associated with MCV-associated fever using multivariate logistic regression analyses. After adjusting for multiple factors, including healthcare utilization, maternal fever [odds ratio (OR) = 1.19, 95% confidence interval (CI) 1.06–1.32], fever after MCV (OR = 5.90, 95% CI 1.35–25.78), respiratory infections (OR = 1.20, 95% CI 1.10–1.31), migraine (OR = 1.14, 95% CI 1.05–1.24), syncope (OR 1.14, 95% CI 1.01–1.27), and essential thrombocythemia (OR = 1.93, 95% CI 1.15–3.25) were significantly associated with MCV-associated fever. Paternal respiratory infections (OR = 1.15, 95% CI 1.05–1.27), fever associated with respiratory infections (OR = 1.47, 95% CI 1.23–1.76), and vitiligo (OR = 1.63, 95% CI 1.06–2.53) were significantly associated with MCV-associated fever. Parental clinical conditions, specifically fever alone and fever associated with respiratory infection, are associated with fever in their child 7–10 days after MCV.

Factors That Influence the Immune Response to Vaccination

There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal factors (such as gestational age, birth weight, feeding method, and maternal factors), and extrinsic factors (such as preexisting immunity, microbiota, infections, and antibiotics). Further, environmental factors (such as geographic location, season, family size, and toxins), behavioral factors (such as smoking, alcohol consumption, exercise, and sleep), and nutritional factors (such as body mass index, micronutrients, and enteropathy) also influence how individuals respond to vaccines. Moreover, vaccine factors (such as vaccine type, product, adjuvant, and dose) and administration factors (schedule, site, route, time of vaccination, and coadministered vaccines and other drugs) are also important. An understanding of all these factors and their impacts in the design of vaccine studies and decisions on vaccination schedules offers ways to improve vaccine immunogenicity and efficacy.

Current perspectives in assessing humoral immunity after measles vaccination

INTRODUCTION

Repeated measles outbreaks in countries with relatively high vaccine coverage are mainly due to failure to vaccinate and importation; however, cases in immunized individuals exist raising questions about suboptimal measles vaccine-induced humoral immunity and/or waning immunity in a low measles-exposure environment.

AREAS COVERED

The plaque reduction neutralization measurement of functional measles-specific antibodies correlates with protection is the gold standard in measles serology, but it does not assess cellular-immune or other parameters that may be associated with durable and/or protective immunity after vaccination. Additional correlates of protection and long-term immunity and new determinants/signatures of vaccine responsiveness such as specific CD46 and IFI44L genetic variants associated with neutralizing antibody titers after measles vaccination are under investigation. Current and future systems biology studies, coupled with new technology/assays and analytical approaches, will lead to an increasingly sophisticated understanding of measles vaccine-induced humoral immunity and will identify 'signatures' of protective and durable immune responses.

EXPERT OPINION

This will translate into the development of highly predictive assays of measles vaccine efficacy, effectiveness, and durability for prospective identification of potential low/non-responders and susceptible individuals who require additional vaccine doses. Such new advances may drive insights into the development of new/improved vaccine formulations and delivery systems.

Comparison of the Immunogenicities and Cross-Lineage Efficacies of Live Attenuated Peste des Petits Ruminants Virus Vaccines PPRV/Nigeria/75/1 and PPRV/Sungri/96

Despite the widespread use of live attenuated PPRV vaccines, this is the first systematic analysis of the immune response elicited in small ruminants. These data will help in the establishment of the immunological determinants of protection, an important step in the development of new vaccines, especially DIVA vaccines using alternative vaccination vectors. This study is also the first controlled test of the ability of the two major vaccines used against virulent PPRV strains from all genetic lineages of the virus, showing conclusively the complete cross-protective ability of these vaccines.

Peste des petits ruminants (PPR) is a severe disease of goats and sheep that is widespread in Africa, the Middle East, and Asia. Several effective vaccines exist for the disease, based on attenuated strains of the virus (PPRV) that causes PPR. While the efficacy of these vaccines has been established by use in the field, the nature of the protective immune response has not been determined. In addition, while the vaccine derived from PPRV/Nigeria/75/1 (N75) is used in many countries, those developed in India have never been tested for their efficacy outside that country. We have studied the immune response in goats to vaccination with either N75 or the main Indian vaccine, which is based on isolate PPRV/India/Sungri/96 (S96). In addition, we compared the ability of these two vaccines, in parallel, to protect animals against challenge with pathogenic viruses from the four known genetic lineages of PPRV, representing viruses from different parts of Africa, as well as Asia. These studies showed that, while N75 elicited a stronger antibody response than S96, as measured by both enzyme-linked immunosorbent assay and virus neutralization, S96 resulted in more pronounced cellular immune responses, as measured by virus antigen-induced proliferation and interferon gamma production. While both vaccines induced comparable numbers of PPRV-specific CD8⁺ T cells, S96 induced a higher number of CD4⁺ T cells specifically responding to virus. Despite these quantitative and qualitative differences in the immune responses following vaccination, both vaccines gave complete clinical protection against challenge with all four lineages of PPRV.

IMPORTANCE Despite the widespread use of live attenuated PPRV vaccines, this is the first systematic analysis of the immune response elicited in small ruminants. These data will help in the establishment of the immunological determinants of protection, an important step in the development of new vaccines, especially DIVA vaccines using alternative vaccination vectors. This study is also the first controlled test of the ability of the two major vaccines used against virulent PPRV strains from all genetic lineages of the virus, showing conclusively the complete cross-protective ability of these vaccines.

Genetic Variants in the IL-4/IL-13 Pathway Influence Measles Vaccine Responses and Vaccine Failure in Children from Mozambique

Despite effective measles vaccines, measles still causes severe morbidity and mortality worldwide, particularly in developing countries. The Th2 pathway involving interleukin (IL)-4 and IL-13 cytokines, and their receptor IL-4Rα, play important roles in the Th1/Th2 balance and antibody production. A Th2 skewing of the cytokine milieu may affect vaccine responses. We investigated IL-4, IL-13, and IL-4Rα polymorphisms and their impact on measles IgG responses and measles vaccine failure, in two separate cohorts: 12-month-old Australian children immunized with measles-mumps-rubella vaccine (n = 137) and a case/control cohort of children aged 6 months-14 years from Mozambique, Africa (n = 89), some of whom were vaccinated, but still contracted measles (vaccine failure). We found that IL-4Rα haplotypes for Val75Ile, Ser503Pro, and Arg576Gln were associated with measles IgG in Mozambican children (p = 0.016 and p = 0.032 for Val.Pro.Arg and Val.Ser.Arg, respectively), but not Australian children. IL-4Rα 503Pro was more prevalent in Mozambique vaccine failure cases compared with controls (p = 0.008). We showed that the impact of Th2 genes on measles vaccine responses differs between ethnicities and IL-4Rα polymorphisms may work in combination to affect measles antibody responses and vaccine failure in Mozambican children. Studies in this area are particularly important in developing countries like Mozambique where measles is still a major health issue.

Risk factors and familial clustering for fever 7-10days after the first dose of measles vaccines

BACKGROUND

Seven to ten days after a first dose of a measles-containing vaccine (MCV; i.e., MMR or MMRV), children have elevated fever risk which can be associated with febrile seizures. This study investigated individual and familial factors associated with fever 7-10days after MCV.

METHODS

Retrospective cohort study among children who were <36months of age at receipt of MCV in six sites of the Vaccine Safety Datalink from 1/1/2000 to 12/31/2012. We evaluated medically-attended clinic or emergency department visits with a code for fever 7-10days after any MCV ("MCV- associated"). We evaluated factors associated with MCV-associated fever using χ² and multivariable logistic regression analyses.

RESULTS

Among 946,806 children vaccinated with MCV, we identified 7480 (0.8%) MCV-associated fever visits. Compared with children without fever after MCV, children with MCV-associated fever were more likely to have received MMRV than MMR (OR 1.3 95% CI 1.2, 1.5), have had medically attended fever both following previous vaccines (OR 1.3 95% CI 1.1, 1.6) and at any other previous time (OR 1.7 95% CI 1.6, 1.8), have had at least 1 prior seizure (OR 2.2 95% CI 1.7, 2.7), and have had >3 medical visits within the 6months before MCV (OR 1.7 95% CI 1.6, 1.8). In families with multiple MCV-immunized children, after adjusting for healthcare seeking behavior care for fever, those whose siblings had MCV-associated fever were more likely to also have MCV-associated fever (OR 3.5 95% CI 2.5, 4.8).

DISCUSSION

Children who received MMRV vaccine or who had prior medically-attended fevers and seizures during the first year of life had increased risk of fever after a first dose of measles vaccine. After adjusting for familial propensity to seek care, MCV-associated fever still clustered within families, suggesting a possible genetic basis for susceptibility to developing fever due to measles vaccines.

Genetically defined race, but not sex, is associated with higher humoral and cellular immune responses to measles vaccination

In addition to host genetic and environmental factors, variations in immune responses to vaccination are influenced by demographic variables, such as race and sex. The influence of genetic race and sex on measles vaccine responses is not well understood, yet important for the development of much-needed improved measles vaccines with lower failure rates. We assessed associations between genetically defined race and sex with measles humoral and cellular immunity after measles vaccination in three independent and geographically distinct cohorts totaling 2872 healthy racially diverse children, older adolescents, and young adults. We found no associations between biological sex and either humoral or cellular immunity to measles vaccine, and no correlation between humoral and cellular immunity in these study subjects. Genetically defined race was, however, significantly associated with both measles vaccine-induced humoral and cellular immune responses, with subjects genetically classified as having African-American ancestry demonstrating significantly higher antibody and cell-mediated immune responses relative to subjects of Caucasian ancestry. This information may be useful in designing novel measles vaccines that are optimally effective across human genetic backgrounds.

Common haplotypes in CD209 promoter and susceptibility to HIV-1 infection in intravenous drug users

INTRODUCTION

CD209 is a receptor expressed in the dendritic cells involved in recognition of oligosaccharides present in several pathogens with a relevant impact on human health. SNPs located in the promoter region have been associated with HIV-1 susceptibility, although this finding has not been replicated in other populations. The objective of this study is to evaluate the association of CD209 promoter haplotypes with risk of HIV-1 infection in a cohort of Spanish male intravenous drug users (IDU) infected with hepatitis C virus (HCV) and to characterize the phenotypic effects of the associated variants.

METHODS

We genotyped 4 SNPs of CD209 promoter in 295 HCV males exposed to HIV-1 infection by IDU, 165 HIV-1-infected and 130 exposed uninfected (EUI) and 142 healthy controls (HC). We have cloned the promoter variants in a reporter vector and evaluated the promoter activities in a cell culture model. CD209 mRNAs were measured in PBMC.

RESULTS

Single-marker analysis revealed no significant allelic association with the risk of HIV-1 infection by parenteral route. Nevertheless, one haplotype was significantly overrepresented in EUI compared with HIV-1 positive patients and was associated with HIV-1 status (P=0.0008; OR: 0.43). Functional experiments suggested that the protective haplotype displayed lower transcriptional activity in vitro (P<0.05) and this was correlated with lower CD209 mRNA expression in PBMC (P=0.014).

CONCLUSIONS

This study suggests that the promoter haplotypes of CD209 influence the risk of HIV-1 acquisition in IDU and that this association is correlated with the mRNA expression level.

Variability in Humoral Immunity to Measles Vaccine: New Developments

Despite the existence of an effective measles vaccine, resurgence in measles cases in the USA and across Europe has occurred, including in individuals vaccinated with two doses of the vaccine. Host genetic factors result in inter-individual variation in measles vaccine-induced antibodies, and play a role in vaccine failure. Studies have identified HLA (human leukocyte antigen) and non-HLA genetic influences that individually or jointly contribute to the observed variability in the humoral response to vaccination among healthy individuals. In this exciting era, new high-dimensional approaches and techniques including vaccinomics, systems biology, GWAS, epitope prediction and sophisticated bioinformatics/statistical algorithms provide powerful tools to investigate immune response mechanisms to the measles vaccine. These might predict, on an individual basis, outcomes of acquired immunity post measles vaccination.

Association of Oligoadenylate Synthetase Gene Cluster and DC-SIGN (CD209) Gene Polymorphisms with Clinical Symptoms in Chikungunya Virus Infection

Biology and pathogenesis of chikungunya virus (CHIKV) are not clearly established. Host factors play an important role in determining the progression and severity of the disease. Polymorphisms in the promoter region of CD209 gene (rs735239, rs4804803, rs2287886) and OAS1 (rs1131454 and rs10774671), OAS2 (rs15895 and rs1732778), and OAS3 (rs2285932 and rs2072136) genes were investigated in 100 patients with CHIKV infection and 101 healthy controls to find out the association of these polymorphisms with CHIKV infection. To evaluate the association of OAS and CD209 gene polymorphisms with the presence or absence of disease symptoms in CHIKV-infected patients. DNA was extracted and typed using polymerase chain reaction followed by restriction fragment length polymorphism methods. Results revealed that the allele and genotype frequencies of OAS1, OAS3, and OAS2 gene polymorphisms were not different between healthy controls and CHIKV patients. The frequency of CD209 gene G/G genotype of rs4804803 was significantly higher in CHIKV patients compared to healthy controls (p = 0.046). The present study suggests that rs4804803 GG genotype of CD209 gene is associated with susceptibility to CHIKV infection. To conclude, the present preliminary study suggests that OAS gene cluster and CD209 gene polymorphisms influence the risk of developing clinical symptoms in CHIKV-infected patients. Further follow-up studies with a large number of samples are needed to assess the role of these genes in association with post-sequela symptoms observed in CHIKV patients. A detailed research is required in these directions to understand the biology behind CHIKV infection and disease severity.

Associations between single nucleotide polymorphisms in cellular viral receptors and attachment factor-related genes and humoral immunity to rubella vaccination

Background

Viral attachment and cell entry host factors are important for viral replication, pathogenesis, and the generation and sustenance of immune responses after infection and/or vaccination, and are plausible genetic regulators of vaccine-induced immunity.

Methods

Using a tag-SNP approach in candidate gene study, we assessed the role of selected cell surface receptor genes, attachment factor-related genes, along with other immune genes in the genetic control of immune response variations after live rubella vaccination in two independent study cohorts.

Results

Our analysis revealed evidence for multiple associations between genetic variants in the PVR, PVRL2, CD209/DC-SIGN, RARB, MOG, IL6 and other immune function-related genes and rubella-specific neutralizing antibodies after vaccination (meta p-value <0.05).

Conclusion

Our results indicate that multiple SNPs from genes involved in cell adhesion, viral attachment, and viral entry, as well as others in genes involved in signaling and/or immune response regulation, play a role in modulating humoral immune responses following live rubella vaccination.

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.

Polymorphisms in key innate immune genes and their effects on measles vaccine responses and vaccine failure in children from Mozambique

Despite an effective vaccine, measles remains a major health problem globally, particularly in developing countries. More than 30% of children show primary vaccine failure and therefore remain vulnerable to measles. Genetic variation in key innate pathogen recognition receptors, such as the measles cell entry receptors CD46 and SLAM, measles attachment receptor DC-SIGN, the antiviral toll-like receptors (TLR)3, TLR7 and TLR8, and the cytosolic antiviral receptor RIG-I, may significantly affect measles IgG antibody responses. Measles is still highly prevalent in developing countries such as those in Africa however there is no previous data on the effect of these innate immune genes in a resident African population. Polymorphisms (n=29) in the candidate genes were genotyped in a cohort of vaccinated children (n=238) aged 6 months-14 years from Mozambique, Africa who either had vaccine failure and contracted measles (cases; n=66) or controls (n=172). Contrasting previous associations with measles responses in Caucasians and/or strong evidence for candidacy, we found little indication that these key innate immune genes affect measles IgG responses in our cohort of Mozambican children. We did however identify that CD46 and TLR8 variants may be involved in the occurrence of measles vaccine failure. This study highlights the importance of genetic studies in resident, non-Caucasian populations, from areas where determining the factors that may affect measles control is of a high priority.

TLR3 and RIG-I gene variants: associations with functional effects on receptor expression and responses to measles virus and vaccine in vaccinated infants

Measles virus causes severe morbidity and mortality, despite the availability of measles vaccines. Successful defence against viral pathogens requires early recognition of virus-specific patterns by innate receptors like Toll-like receptor (TLR)3 and the RNA helicase, retinoic acid inducible gene-I (RIG-I). Genetic differences in these receptors may influence the primary immune responses to measles and the efficacy of measles vaccine. In 1-year-old Australian infants after their first measles vaccine dose, we investigated functional effects of TLR3 and RIG-I polymorphisms on intracellular protein expression using flow cytometry, cytokine responses to receptor ligands and measles lysate, and post-vaccination measles IgG levels. We found that TLR3 Leu412Phe was significantly associated with IFN-α/β response after stimulation with TLR3 ligand, poly(I:C) (P=0.024). Downregulation of TLR3 protein expression in NK cells after poly(I:C) was also associated with this variant (P=0.011). In contrast, measles-specific expression, cytokine responses and antibody responses were not associated with TLR3 polymorphisms. No associations were found with RIG-I variants. These results suggest that a TLR3 polymorphism has functional effects on receptor expression and cytokine response. However, this did not translate to an effect on specific responses to measles virus or vaccine. We found no evidence that RIG-I polymorphisms were involved in measles immune responses.

CD46 measles virus receptor polymorphisms influence receptor protein expression and primary measles vaccine responses in naive Australian children

Despite the availability of measles vaccines, infants continue to die from measles. Measles vaccine responses vary between individuals, and poor immunogenicity is likely to preclude protection against measles. CD46 is a ubiquitously expressed specific receptor for vaccine strains of measles virus. CD46 polymorphisms have not been functionally investigated but may affect CD46 protein expression, which in turn may mediate primary measles antibody responses in infants. In a cohort of children aged 12 to 14 months from Perth, Australia (n = 137), after their first dose of measles-mumps-rubella (MMR) vaccine, CD46 polymorphisms were genotyped, and postvaccination measles IgG and CD46 protein expression before and after measles lysate stimulation of cells were measured. Three CD46 variants (rs7144, rs11118580, and rs2724384) were significantly associated with measles virus-specific IgG levels (P = 0.008, P = 0.026, and P = 0.018, respectively). There were significant differences between CD46 rs7144 genotypes and CD46 protein expression on T cells, as well as the downregulation of CD46 and T-cell frequency after measles lysate stimulation. We show that CD46 polymorphisms were associated with primary measles antibody responses in naive infants. We also report the first association of a measles virus receptor polymorphism with functional effects on the receptor, suggesting a possible mechanism through which antibody responses are altered. Elucidating all of the interconnecting genetic factors that alter primary measles vaccine responses may be important for identifying children at risk of poor immunogenicity or vaccine failure and for the future design of vaccine strategies to help these children.

Genetic polymorphisms in host antiviral genes: associations with humoral and cellular immunity to measles vaccine

Host antiviral genes are important regulators of antiviral immunity and plausible genetic determinants of immune response heterogeneity after vaccination. We genotyped and analyzed 307 common candidate tagSNPs from 12 antiviral genes in a cohort of 745 schoolchildren immunized with two doses of measles-mumps-rubella (MMR) vaccine. Associations between SNPs/haplotypes and measles virus-specific immune outcomes were assessed using linear regression methodologies in Caucasians and African-Americans. Genetic variants within the DDX58/RIG-I gene, including a coding polymorphism (rs3205166/Val800Val), were associated as single-SNPs (p≤0.017; although these SNPs did not remain significant after correction for false discovery rate/FDR) and in haplotype-level analysis, with measles-specific antibody variations in Caucasians (haplotype allele p-value=0.021; haplotype global p-value=0.076). Four DDX58 polymorphisms, in high LD, demonstrated also associations (after correction for FDR) with variations in both measles-specific IFN-γ and IL-2 secretion in Caucasians (p≤0.001, q=0.193). Two intronic OAS1 polymorphisms, including the functional OAS1 SNP rs10774671 (p=0.003), demonstrated evidence of association with a significant allele-dose-related increase in neutralizing antibody levels in African-Americans. Genotype and haplotype-level associations demonstrated the role of ADAR genetic variants, including a non-synonymous SNP (rs2229857/Arg384Lys; p=0.01), in regulating measles virus-specific IFN-γ Elispot responses in Caucasians (haplotype global p-value=0.017). After correction for FDR, 15 single-SNP associations (11 SNPs in Caucasians and 4 SNPs in African-Americans) still remained significant at the q-value<0.20. In conclusion, our findings strongly point to genetic variants/genes, involved in antiviral sensing and antiviral control, as critical determinants, differentially modulating the adaptive immune responses to live attenuated measles vaccine in Caucasians and African-Americans.