Interleukin-4 induced by measles virus and measles-derived peptides as measured by IL-4 receptor-blocking ELISA

Polypharmacological Cell-Penetrating Peptides from Venomous Marine Animals Based on Immunomodulating, Antimicrobial, and Anticancer Properties

Complex pathological diseases, such as cancer, infection, and Alzheimer's, need to be targeted by multipronged curative. Various omics technologies, with a high rate of data generation, demand artificial intelligence to translate these data into druggable targets. In this study, 82 marine venomous animal species were retrieved, and 3505 cryptic cell-penetrating peptides (CPPs) were identified in their toxins. A total of 279 safe peptides were further analyzed for antimicrobial, anticancer, and immunomodulatory characteristics. Protease-resistant CPPs with endosomal-escape ability in Hydrophis hardwickii, nuclear-localizing peptides in Scorpaena plumieri, and mitochondrial-targeting peptides from Synanceia horrida were suitable for compartmental drug delivery. A broad-spectrum S. horrida-derived antimicrobial peptide with a high binding-affinity to bacterial membranes was an antigen-presenting cell (APC) stimulator that primes cytokine release and naïve T-cell maturation simultaneously. While antibiofilm and wound-healing peptides were detected in Synanceia verrucosa, APC epitopes as universal adjuvants for antiviral vaccination were in Pterois volitans and Conus monile. Conus pennaceus-derived anticancer peptides showed antiangiogenic and IL-2-inducing properties with moderate BBB-permeation and were defined to be a tumor-homing peptide (THP) with the ability to inhibit programmed death ligand-1 (PDL-1). Isoforms of RGD-containing peptides with innate antiangiogenic characteristics were in Conus tessulatus for tumor targeting. Inhibitors of neuropilin-1 in C. pennaceus are proposed for imaging probes or therapeutic delivery. A Conus betulinus cryptic peptide, with BBB-permeation, mitochondrial-targeting, and antioxidant capacity, was a stimulator of anti-inflammatory cytokines and non-inducer of proinflammation proposed for Alzheimer's. Conclusively, we have considered the dynamic interaction of cells, their microenvironment, and proportional-orchestrating-host- immune pathways by multi-target-directed CPPs resembling single-molecule polypharmacology. This strategy might fill the therapeutic gap in complex resistant disorders and increase the candidates' clinical-translation chance.

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.

Effects of early measles on later rhinitis and bronchial hyperresponsiveness

BACKGROUND

The hygiene hypothesis suggests that infectious diseases in early life reduce the risk of allergic diseases.

OBJECTIVE

To investigate the association between measles infection during early childhood and the prevalence of allergic diseases, lung function, bronchial hyperresponsiveness (BHR), and sensitization in later childhood.

METHODS

A survey was conducted 5 years after a nationwide measles outbreak in Korea. From September 1 through November 30, 2006, we obtained information on history of measles and allergic diseases but not of measles vaccination through a questionnaire completed by 1004 schoolchildren aged 6 to 7 years. Furthermore, we measured measles antibody titers and performed skin prick tests, pulmonary function tests, and methacholine challenge tests. Children were divided into groups based on their history of measles infection and antibody titers.

RESULTS

Prevalence of measles infection was 8.2%. Children with both a positive measles history and a positive antimeasles antibody had significantly higher antimeasles antibody levels than those without a measles history. The prevalence of current rhinitis (adjusted odds ratio [aOR], 1.86; 95% confidence interval [CI], 1.02-3.40), rhinitis ever (aOR, 2.17; 95% CI, 1.19-3.94), and current BHR (aOR, 1.98; 95% CI, 1.04-3.78) was significantly higher in the group with a positive measles history compared with the group with a negative measles antibody. No differences were found among groups in the prevalence of asthma, lung function, provocation concentration that caused a decrease in forced expiratory volume of 1 second of 20%, or sensitization.

CONCLUSION

Early measles infection was associated with increased prevalence of rhinitis and BHR at the age of 7 years but has no effect on the development of asthma and allergy at the age of 7 years. This study indicates that common childhood infections such as measles in early age do not protect against later development of allergic diseases.

Specific CD8(+) T-lymphocytes control dissemination of measles virus

Measles continues to be an important cause of childhood mortality in developing countries. Measles virus (MV) is lymphotropic and infects high percentages of B- and T-lymphocytes in lymphoid tissues. Cellular immunity is considered crucial for viral clearance; however, MV-specific T-lymphocytes generated during primary infection also constitute a potential target for MV infection. We therefore aimed to identify T-lymphocyte subsets that can clear MV infection without becoming infected. To this end, we infected human EBV transformed B-lymphoblastic cell lines (B-LCL) with a recombinant MV strain expressing enhanced GFP, and co-cultured these with non-infected B-LCL resulting in rapid viral spread. MV-specific CD8(+) T-cell clones efficiently suppressed MV dissemination in autologous and HLA-matched, but not in HLA-mismatched B-LCL. In contrast, CD4(+) T-cell clones could not control MV dissemination but became a target for MV infection themselves. Furthermore, PBMC collected 6-9 months after acute measles and stimulated with autologous MV-infected B-LCL also efficiently suppressed MV dissemination; this was mediated by the fraction containing CD8(+) T-lymphocytes. In conclusion, we have developed a powerful tool to study cellular immunity against measles, and demonstrate that control of MV dissemination is mediated by virus-specific CD8(+) rather than by CD4(+) T-lymphocytes.

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.

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.

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.

Associations between SNPs in toll-like receptors and related intracellular signaling molecules and immune responses to measles vaccine: preliminary results

Toll-like receptors (TLRs) represent the critical "bridge" between innate and adaptive immunity to viral pathogens. We hypothesized that single nucleotide polymorphisms (SNPs) that potentially influence the expression/function of TLRs and their associated intracellular signaling molecules contribute to variations in humoral and cellular immunity to measles vaccine. We genotyped 190 randomly selected subjects (12-18 years old), previously vaccinated with two doses of measles, for known SNPs in TLR 2, 3, 4, 5, 6, 7, 8 and 9, and their associated intracellular signaling genes. Specific SNPs in the TLR 2, 3, 4, 5, 6, MyD88 and MD2 genes were associated with measles-specific humoral and cellular immunity. Heterozygous variants for rs3775291 (Phe412Leu) and rs5743305 (-926 bp in promoter region) of the TLR3 gene were associated with low antibody and lymphoproliferative responses (p <or= 0.02) to measles vaccination. Heterozygous variants for rs4986790 (Gly299Asp) and rs4986791 (Ile399Thr) in the TLR4 gene demonstrated higher levels of (p <or= 0.02) IL-4 secretion. Heterozygous variants for SNPs in TLR5 (rs5744174) and TLR6 (rs5743818) were associated with higher levels of (p <or= 0.02) IFN-gamma secretion. In addition, SNPs in MyD88 and MD2, intracellular molecules that associate with TLRs, also demonstrated associations with variations in antibody and IL-10 production (p <or= 0.03). Thus, we identified specific SNP associations between TLRs and their associated signaling molecules that have a known role in viral immunity and variations in both humoral and cellular immunity following measles vaccination. These data contribute to understanding the immunogenetic mechanisms underlying variations in the immune response to measles vaccine.

HLA supertypes and immune responses to measles–mumps–rubella viral vaccine: Findings and implications for vaccine design

Although the outcome of the immune response to measles-mumps-rubella (MMR) vaccination depends on multiple factors, elucidation of specific host genetic markers, such as HLA supertypes based on a shared sequence motif in the peptide-binding pockets of HLA molecules, is essential. We studied the association between measures of humoral and cellular immune responses and HLA supertypes among 346 children previously immunized with two doses of MMR. We found that HLA supertypes, such as A3, B7, B44, B58, B62, and DR may play a role in modulating immune responses to the measles and mumps components of MMR vaccine. This information may be of significant value in the engineering of potential epitope-based vaccines that are recognized by T cells restricted by human HLA supertype alleles.

HLA homozygosity does not adversely affect measles vaccine-induced cytokine responses

The association between HLA homozygosity and measles-specific Th(1) (IFN-gamma, IL-2 and IL-12p40) and Th(2) (IL-4 and IL-10) cytokine responses were assessed in a group of 339 healthy schoolchildren 12-18 years of age previously immunized with two doses of live-attenuated measles virus vaccine. No associations were observed between class I HLA homozygosity and measles-specific cytokine levels. Children who were homozygous at the class II DRB1, DQA1, DPA1 and DPB1 loci had higher median IFN-gamma secretion levels compared with children who were heterozygous for DRB1 (77.7 vs. 39.5 pg/ml, p=0.05), DQA1 (60.9 vs. 36.6 pg/ml, p=0.03), DPA1 (46.1 vs. 27.1 pg/ml, p=0.01) and DPB1 (61.5 vs. 36.0 pg/ml, p=0.01) loci, respectively. Homozygosity at increasing numbers of HLA loci ( >or=4) was associated with increased IFN-gamma secretion levels (test for trend p-value=0.01). Our results suggest that HLA homozygosity showed no disadvantage for measles-specific cytokine responses and instead was associated with increased IFN-gamma levels.

Cytokine responses in gnotobiotic pigs after infection with virulent or attenuated human rotavirus

To understand the role of cytokines during rotavirus infection, we assessed the kinetics of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) (proinflammatory), IL-12 (Th1 inducer), gamma interferon (IFN-gamma) (Th1), IL-4 and IL-10 (Th2), and transforming growth factor beta (Th3) cytokine responses by enzyme-linked immunosorbent assay in serum and intestinal contents of neonatal gnotobiotic pigs and IL-12, IFN-gamma, IL-4, and IL-10 cytokine-secreting cell (CSC) responses of mononuclear cells from ileum, spleen, and blood by ELISPOT. Pigs received the virulent Wa P1A[8]G1 strain of human rotavirus (HRV) (VirHRV), attenuated Wa HRV (AttHRV), or mock (controls). The TNF-alpha levels peaked earlier and remained elevated in serum of the VirHRV group but peaked later in the AttHRV group. In serum, IL-6 was significantly elevated at postinoculation day (PID) 1 in the VirHRV group and at PID 3 in both HRV groups. The IL-12 was detected in serum of all pigs including controls with significantly elevated peaks in both HRV-infected groups, indicating a role for IL-12 in the induction of immune responses to rotavirus infection. Only low and transient IFN-gamma responses occurred in serum and intestinal contents of the AttHRV-infected pigs, compared to significantly higher and prolonged IFN-gamma responses in the VirHRV-infected pigs. This observation coincides with the diarrhea and viremia induced by VirHRV. The number of IFN-gamma-secreting cells was significantly higher in the ileum of the VirHRV group than in that of the controls. The number of IL-4 CSCs was significantly higher in ileum of both HRV groups than in that of the controls. Significantly higher levels of IL-10 in the serum occurred early in the VirHRV group, compared to lower levels in the AttHRV group. However, the number of IL-10 CSCs was significantly higher later in ileum and spleen of the AttHRV than in the VirHRV group, suggesting a delayed initiation of a Th2 response induced by AttHRV. A significantly higher percentage of pigs had IFN-gamma and IL-10 responses in serum after VirHRV infection than after AttHRV infection or in controls. These data indicate a balanced Th1/Th2 response during rotavirus infection, with higher cytokine levels early after infection with VirHRV compared to that with AttHRV. Mapping the kinetics and patterns of cytokine responses after rotavirus infection has important implications for induction of protective immunity by HRV vaccines. Higher protection rates may be associated with more balanced Th1- and Th2-type responses, but induction of higher earlier IFN-gamma (Th1) and proinflammatory cytokines triggered by VirHRV may also play an important role in the higher intestinal immunoglobulin A responses and protection rates induced by VirHRV.

Interleukin-4 production by human alveolar macrophages

BACKGROUND

IL-4 is a key factor for T helper type 2 (Th2) differentiation and Ig class switching to IgE and IgG(4) during the development of immune responses. IL-4 is produced by T cells, mast cells, basophils, and eosinophils. However, there is also evidence suggesting that rat alveolar macrophages (AMs) produce IL-4.

OBJECTIVE

Given the importance of AMs and Th2-related diseases in the lung, we investigated the production of IL-4 by human AMs.

METHODS

Human AMs were isolated from bronchoalveolar lavage, purified, and IL-4 production was investigated at mRNA and protein levels using real-time PCR, flow cytometry, immunocytochemistry, and ELISA. The presence of IL-4 was investigated in subjects with asthma or asymptomatic airway hyper-responsiveness, and in normal non-smokers.

RESULTS

IL-4 and IL-4delta2 (a splice variant found in other IL-4 producing cells) mRNAs were found in all these subjects, but IL-4 expression could not be correlated with a particular disease. Protein production was verified by immunocytochemistry and flow cytometry analysis demonstrating, respectively, up to 69% and 59% positive AMs, regardless of the subject condition. Furthermore, phorbol-12-myristate-13-acetate and calcium ionophore stimulated the release of IL-4 after 48 h treatment in the presence of anti-IL-4 receptor antibody.

CONCLUSION

Our results show for the first time that IL-4 and IL-4delta2 mRNA are expressed and IL-4 protein produced and released by human AMs, suggesting a contribution of these cells in the modulation of Th2 immune response.

Importance of HLA-DQ and HLA-DP polymorphisms in cytokine responses to naturally processed HLA-DR-derived measles virus peptides

We studied the association between class II human leukocyte antigen (HLA)-DRB1*0301 presented measles virus (MV) peptide-specific cytokine responses and DQB1 and DPB1 alleles among 313 individuals who received two doses of measles-mumps-rubella-II vaccine. The overall median IFN-gamma secretion levels (first and third quartiles) for the 19-amino acid MV phosphoprotein (MV-P)- and 14-amino acid MV nucleoprotein (MV-N)-derived peptides were 27.7 pg/ml (1.8, 109.4) and 1.9 pg/ml (-6.2, 13.0), respectively; median IL-4 secretion levels were -0.6 pg/ml (-7.1, 6.2) and 2.4 pg/ml (-3.2, 9.3), respectively. Primary statistical analyses were adjusted for previously identified DRB1 associations. A marginally significant increase in the frequency of the DQB1*0604 (p=0.02) allele was found among subjects who demonstrated detectable IL-4 levels to the MV-P peptide. Further, DPB1*0201 (p=0.02) and DPB1*1301 (p=0.09) alleles provided suggestive evidence of an association with MV-P-induced IL-4 secretion. Examination of IFN-gamma responses to MV-P and MV-N indicated that none of the individual alleles of the DQB1 and DPB1 loci were associated with peptide-induced T cell response. An increase in the frequency of DPB1*0501 (p=0.01) was found among subjects who failed to produce MV-N peptide-specific IL-4 responses. These data further confirm that HLA-DRB1 alleles are the major restriction molecules for MV-P and MV-N measles virus antigen presentation to T cells. We speculate that MV-P and MV-N peptides derived from DRB1*0301 could potentially be recognized in association with different HLA molecules, including DQB1 and DPB1; however, statistical adjustments for the effect of HLA-DR locus could potentially alter these genetic relationships. This concept provides important information supporting the use of promiscuous peptides in a peptide-based vaccine approach.

Inter-operator variation in ELISPOT analysis of measles virus-specific IFN-gamma-secreting T cells

The ELISPOT assay is a highly sensitive technique used for the detection of individual cytokine releasing cells. We have developed an IFN-gamma ELISPOT assay utilizing unfractionated frozen peripheral blood mononuclear cells (PBMC) to quantify the frequency of measles virus (MV)-specific IFN-gamma-secreting T cells in 117 healthy children who had been previously immunized with two doses of the measles-mumps-rubella vaccine. We have also estimated the variability associated with the quantification of ELISPOT plates and compared the number of MV-specific IFN-gamma-secreting T cells for each subject as determined by two different operators of an ELISPOT reader. The median frequency of MV-specific IFN-gamma-producing memory T cells detected by this assay was 0.005 % and 0.01 % as determined by an in-house and commercial operator, respectively. Although we found a significant correlation (r = 0.83, p<0.0001) between the number of spots counted by the commercial and in-house operators of an ELISPOT reader, the median number of spots counted by the commercial operator was twice the number of spots counted by an in-house operator (p<0.001). This demonstrates the importance of using a common ELISPOT reader and operator, among other parameters, to quantify the number of spots when a large volume of plates are being scanned and analyzed.

Correlations among measles virus-specific antibody, lymphoproliferation and Th1/Th2 cytokine responses following measles-mumps-rubella-II (MMR-II) vaccination

Immunity to measles is conferred by the interplay of humoral and cellular immune responses, the latter being critical in maintaining long-term recall response. Therefore, it is important to evaluate measles-specific humoral and cellular immunity in populations several years after vaccination and understand the correlations among these measures of immunity. We examined measles-specific antibodies, lymphoproliferation and the Th1/Th2 signature cytokines, interferon (IFN)-gamma and interleukin (IL)-4, in a population-based cohort of healthy children from Olmsted County, Minnesota after two doses of measles-mumps-rubella-II (MMR-II) vaccine. We detected positive measures of measles-specific cellular and humoral immunity in the majority of our study population. However, a small proportion of subjects demonstrated an immune response skewed towards the Th2 type, characterized by the presence of either IL-4 and/or measles-specific antibodies and a lack of IFN-gamma production. Further, we observed a significant positive correlation between lymphoproliferation and secretion of IFN-gamma (r = 0.20, P = 0.0002) and IL-4 (r = 0.15, P = 0.005). Measles antibody levels were correlated with lymphoproliferation (r = 0.12, P = 0.03), but lacked correlation to either cytokine type. In conclusion, we demonstrated the presence of both long-term cellular and humoral responses after MMR-II vaccination in a significant proportion of study subjects. Further, a positive correlation between lymphoproliferation and IL-4 and IFN-gamma suggests that immunity to measles may be maintained by both Th1 and Th2 cells. We speculate that the Th2 biased response observed in a subset of our subjects may be insufficient to provide long-term immunity against measles. Further examination of the determinants of Th1 versus Th2 skewing of the immune response and long-term follow-up is needed.

Immune activation at effector and gene expression levels after measles vaccination in healthy individuals: a pilot study

Cellular immunity to measles vaccination is not fully understood at the effector response and gene expression levels. We enrolled 15 healthy individuals (15-25 years old) previously vaccinated with two doses of measles-mumps-rubella-II vaccine to characterize their cellular immunity. We detected a spectrum of lymphoproliferative response (median stimulation indices of 3.4), low precursor frequencies of interferon-gamma (median 0.11%) and interleukin-4 (median 0.05%) by Elispot, and cosecretion of Th1 and Th2 cytokines after measles virus stimulation. Further, global gene expression was examined in five subjects from this cohort after vaccination with an additional dose of measles vaccine (Attenuax, Merck) to identify the genes involved in measles immunity. Linear mixed effect models were used to identify genes significantly up or downregulated in vivo between baseline and Days 7 and 14 after measles vaccination. Measles vaccination induced upregulation of a set of 80 genes, which play a role in measles immunity, signal transduction, apoptosis, cell proliferation, and metabolic pathways. Among the 34 genes that were downregulated, only interferon-alpha is known to have a direct role in measles immunity. This study suggests that measles vaccination leads to activation of multiple cellular mechanisms that can override the immunosuppressant effects of the measles virus and induce immunity.

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

The variability of immune responses modulated by human leukocyte antigen (HLA) genes and secreted cytokines is a significant factor in the development of a protective effect of measles vaccine. We studied the association between type 1 helper T cells (Th1)- and Th2-like cytokine immune responses and HLA class I alleles among 339 schoolchildren who previously received two doses of the measles vaccine. Median values for measles-specific interferon gamma (IFN-gamma) and interleukin-4 (IL-4) cytokines were 40.7 pg/ml [interquartile range (IQR) 8.1-176.7] and 9.7 pg/ml (IQR 2.8-24.3), respectively. Class I HLA-A (*0101 and *3101) and HLA-Cw (*0303 and *0501) alleles were significantly associated with measles-virus-induced IFN-gamma secretion. HLA-A*3101 and Cw*0303 were associated with a higher median IFN-gamma response, while A*0101 and Cw*0501 were associated with lower measles-specific IFN-gamma response. We found limited associations between HLA class I gene polymorphisms and Th2-like (IL-4) immune responses after measles vaccination, indicating that HLA class I molecules may have a limited effect on measles-vaccine-induced IL-4 secretion. Understanding the genetic factors that influence variations in cytokine secretion following measles vaccination will provide insight into the factors that influence both cell-mediated and humoral immunity to measles.

In vitro suppression of human immunodeficiency virus type 1 replication by measles virus

During the acute phase of measles, human immunodeficiency virus type 1 (HIV-1)-infected children have a transient, but dramatic, decrease in plasma HIV-1 RNA levels (W. J. Moss, J. J. Ryon, M. Monze, F. Cutts, T. C. Quinn, and D. E. Griffin, J. Infect. Dis. 185:1035-1042, 2002). To determine the mechanism(s) by which coinfection with measles virus (MV) decreases HIV-1 replication, we established an in vitro culture system that reproduces this effect. The addition of MV to CCR5- or CXCR4-tropic HIV-1-infected human peripheral blood mononuclear cells (PBMCs) decreased HIV-1 p24 antigen production in a dose-dependent manner. This decrease occurred with the addition of MV before or after HIV-1. The inhibition of HIV-1 p24 antigen production was decreased when UV-inactivated MV or virus-free supernatant fluid from MV-infected PBMCs was used. Inhibition was not due to increased production of chemokines known to block coreceptor usage by HIV-1, a decrease in the percentage of CD4+ T cells, or a decrease in chemokine receptor expression by CD4+ T cells. Viability of PBMCs was decreased only 10 to 20% by MV coinfection; however, lymphocyte proliferation was decreased by 60 to 90% and correlated with decreased production of p24 antigen. These studies showed that an in vitro system of coinfected PBMCs could be used to dissect the mechanism(s) by which MV suppresses HIV-1 replication in coinfected children and suggest that inhibition of lymphocyte proliferation by MV may play a role in the suppression of HIV-1 p24 antigen production.

Induction of CD4 T cell proliferation and in vitro Th1-like cytokine responses to measles virus

Mechanisms that lead to induction of life-long immunity to measles virus (MV) are poorly understood. In the present study, we have assessed the activation, proliferation and cytokine secreting function of peripheral blood T cells from MV immune individuals. Expression of cell blastogenesis markers, such as increased forward light scatter and CD38 expression, peaked 5-7 days after infection of peripheral blood mononuclear cells (PBMC) with the live attenuated Edmonston strain of MV. Subset analysis revealed that both CD3- and CD3+ cells expressed activation markers but that the CD3+ T cells predominated late in the culture period corresponding to maximal proliferation and cell recovery. The majority of CD3+ T cells consisted of CD4+CD8- cells. IFN-gamma and IL-4 production similarly showed optimal production late in culture. Depletion of CD4 cells prior to culture and MV stimulation completely abrogated both IFN-gamma and IL-4 production, whereas depletion of CD8 cells did not diminish production, suggesting that CD4+CD8- T cells were principally involved in production of these cytokines. Finally, optimal IFN-gamma production was elicited at high MV doses and IL-4 at much lower doses. These results suggest that among MV immune individuals, in vitro responses to measles are dominated by CD4+ T cells that, depending on antigen dose, primarily produce a Th1-like and, to a lesser extent, a Th1/Th2-mixed pattern of cytokine release.

Identification of Th0 cells responding to measles virus

Mechanisms involved in the induction of immunity to measles virus (MV) are not well understood. In the present study, we assessed proliferation, interferon (IFN)-gamma, and interleukin (IL)-4 production of MV-specific T cells after secondary in vitro stimulation of peripheral blood mononuclear cells (PBMCs) from human donors. Such secondary stimulation resulted in responses substantially higher than after primary in vitro exposure. Most study participants produced both IFN-gamma and IL-4 after secondary in vitro stimulation. Patterns of secondary in vitro responses that use genetically disparate antigen-presenting cells were consistent with T-cell recognition restricted to human leukocyte antigen class II molecules. Limiting dilution analyses indicated that precursor frequencies of cytokine secreting and proliferating cells ranged from about 0.001% to 0.1% among fresh PBMCs. Split-well analyses of limiting dilution cultures suggested that virtually all putative T-cell clones produced either IFN-gamma alone or both IFN-gamma and IL-4. Intracytoplasmic flow cytometric analysis of polyclonal MV-specific secondary in vitro responding T cells revealed a similar pattern of cytokine expression. These results suggest that memory T cells responding in vitro to MV generate cells that produce either IFN-gamma alone (and resemble Th1-like cells) or secreted both IFN-gamma and IL-4 (resembling Th0-like cells) in vitro with few cells expressing a Th2-like pattern.

HLA class II alleles and measles virus-specific cytokine immune response following two doses of measles vaccine

Measles virus-specific T cells and the production of cytokines play a critical role in the immune response following measles immunization. To understand the genetic factors that influence variation in IFN-gamma and IL-4 responses following measles immunization and to provide insight into the factors influencing both cellular and humoral immunity to measles, we assessed associations between human leukocyte antigen (HLA) class II genes and measles-specific Th1 and Th2-type cytokine responses in peripheral blood lymphocytes from 339 children previously vaccinated with two doses of measles-mumps-rubella vaccine (MMR-II). Median values for measles-specific IFN-gamma and IL-4 secretion levels were 40.73 and 9.71 pg/ml, respectively. The global tests suggested associations between measles-specific IFN-gamma response and alleles of the DRB1 and DQB1 loci (P=0.07 and P=0.02, respectively). Specifically, DRB1*0301, *0901, and *1501 alleles were significantly associated with IFN-gamma secretion. The alleles that suggested evidence of an HLA association with IL-4 secretion were DRB1*0103, *0701, and *1101. Th1 cytokine responses and DQB1 allele associations revealed that the alleles with the strongest association with IFN-gamma secretion were DQB1*0201, *0303, *0402, and *0602. Specific alleles with a suggestive association with low measles-specific Th2 cytokine responses were DQB1*0202 and *0503. In addition, DPB1*0101, *0201, and *0601 alleles provided suggestive evidence of an HLA association with measles-induced IFN-gamma response, while DPB1*0501 was associated with an IL-4 response. These data suggest that IFN-gamma and IL-4 cytokine responses to measles may be genetically restricted in part by HLA class II genes, which in turn can restrict the cellular immune response to measles vaccine.