Genetic Factors of Low-responsiveness to Hepatitis B Virus Vaccine Confirms the Importance of Human Leukocyte Antigen Class II Types in a Japanese Young Adult Population

We investigated the genetic mechanisms underlying the association between human leukocyte antigen (HLA) types and the immune response to hepatitis B virus (HBV) vaccination in 84 healthy Japanese adults, and found that the HLA-DRB1＊04 and HLA-DQB1＊03 frequencies were higher in the low responders (<10 mIU/ml; n=9, 10.7%) compared to the responders (≥10 mIU/ml, n=75, 89.3%). The combination of DRB1＊04 and DQB1＊03 was associated with a low response to vaccination. The DRB1＊04 and DQB1＊03 haplotypes’ frequencies were significantly higher in the low responders compared to responders. Novel candidate HLA types may be important in Japanese individuals

Differences in Cytokine Gene Expression after a Stimulation with Escherichia Coli and Porphyromonas Gingivalis or Lipopolysaccharides Derived from these Bacteria

Monocytes are important cells in innate immunity. The early stage of the innate immunity is regulated by various cytokines produced by monocytes. We conducted a preliminary study to investigate TNFα expression by stimulating THP-1 cells with several bacterial species. The TNFα mRNA levels significantly varied, with the most potent stimulatory effects observed with P. gingivalis. In the present study, we focused on P. gingivalis and compared differences in cytokine expression profiles after the stimulation of THP-1 with E. coli. Bacterial antigen stimulation increased various cytokine gene expressions in THP-1. P. gingivalis had significantly more potent effects on the mRNA expressions of TNFα, IL-1β, and IL-10, but not of IL-12p40, than E. coli. This result suggests the potent ability of P. gingivalis to induce inflammation. THP-1 stimulated with LPS derived from both bacterial species showed that E. coli had significantly more potent effects on the expressions of TNFα, IL-1β, and IL-12p40 than P. gingivalis. The differences in the bacterial antigens and the LPS stimulation effects suggest involvements of different receptors, such as TLR-2 and -4, which recognize bacterial components. The present results suggest that the P. gingivalis somatic cell antigen stimulates a number of pattern recognition receptors at the same time as the synthesis of bacterial components, except LPS. The potent virulence of P. gingivalis and persistence of infection might be affected by differences in cytokine production. Pro-inflammatory responses are dependent not only on the bacterial type, but also bacterial components

Influence of single nucleotide polymorphisms of cytokine genes on anti-HBs antibody production after hepatitis B vaccination in a Japanese young adult population

Hepatitis B (HB) vaccination is one of the most efficient tools to prevent the transmission of the virus. Considerable variability exists in HB vaccine responses, with 5-10% of healthy Japanese adults demonstrating no response following a standard vaccination. Recently, polymorphisms of immune-regulatory genes, such as cytokine genes, have been reported to influence the immune response to HB vaccine. The aim of this study was to investigate the underlying mechanisms of the genetic association between several cytokine gene polymorphisms and the immune response to HB vaccination in a Japanese population. One hundred and twenty three vaccinated young adults were classified according to the level of antibody-titer (anti-HBs). Single nucleotide polymorphism typing for IFN-γ(+874, 3’-UTR), IL-10 (−591, −819, −1082), and TNF-α(−308, −857), was accomplished using the PCR-RFLP or SSP-PCR method. The TNF-α(−857) CC type and the IL-10 (−1082) AG type were present more frequently in the low titer group than in the high titer group. The TNF-α(−857) CC type was found to be significantly associated with low response of serum anti-HBs. The anti-HBs antibody was not readily produced in the IL-10 (−1082) AG and TNF-α(−857) CC haplotype. Conversely, the antibody was readily produced in the IL-10 (−1082) AA and TNF-α(−857) CC haplotype, and the IL-10 (−1082) AA and TNF-α(−857) CT haplotype, suggesting a high likelihood of the IL-10 (−1082) AG type to be included in the low anti-HBs group, and high anti-HBs antibody production in those with the TNF-α(−857) CT type. These SNPs may produce ethnically-specific differences in the immune response to HB vaccine in the Japanese population

Evaluation of Surface CD56 Expression

Surface CD56 is the most important cell marker for defining NK cells. However, the relationship between the expression of surface CD56 and NK cell activity has not yet been elucidated in detail. Thirteen healthy volunteers were enrolled in the present study. Peripheral blood mononuclear cells (PBMCs) were stimulated with rIL-2 or rIL-12 (1, 10, 100 U/mL) for 18 h at 37 ℃. After incubation, surface CD56 expression on NK cells was evaluated using a flow cytometric analysis. A colorimetric-based lactate dehydrogenase (LDH) assay was used for experiments on cytotoxicity. IFN-γmRNA gene expression was quantified by real-time PCR. The expression level of surface CD56 on NK cells, cytotoxicity, and IFN-γmRNA gene expression were significantly increased by the rIL-2 and rIL-12 stimulations. In addition, a positive correlation was found between surface CD56 expression and cytotoxic activity or IFN-γmRNA gene expression. We revealed that the quantification of surface CD56 expression was applicable to the evaluation of cytotoxicity and IFN-γproduction in activated NK cells. These results suggest that the measurement of surface CD56 expression represent an easy and rapidly reproducible technique to evaluate the activated state of NK cells and monitor NK cell activity in immunotherapy