HIV-1 Specific Cellular Immune Responses In Hiv-1-monoinfected And HIV-1/HCV-coinfected Individuals

As Acquired Immunodeficiency Syndrome (AIDS) becoming one of the serious infectious diseases impact the health of mankind, researches on it deepens quickly. Cell-mediated immunity, especially the HIV-1 specific cytotoxic T lymphocyte (CTL) is the most important during the process of HIV/AIDS. The enzyme-linked immunosorbent spot (ELISpot) assay is one of the most commonly used methods to measure the CTL immune response in human, which can measure a broad range of magnitudes of CTL response. The following investigations quantitate the secreting cells of Interferon-γ(IFN-γ) by forming a single spot with a single cell, which represent the value to the magnitudes of CTL response. As we all know that except CD8~+T lymphocyte, CD4~+T lymphocyte and non-specific cells(e.g. nature killer cells) also produce IFN-γ. This will impact the quantity of spot forming cells (SFC), and then the magnitudes of CTL response. Moreover, most peripheral blood mononuclear cells (PBMC) were used to study the HIV-1 antigen specific CD4~+/CD8~+T lymphocyte immune responses in previous researches. Though there have been some foreign researches directly aimed at HIV-1 specific CD4~+/CD8~+T lymphocyte immune responses, few reports in China, so it's of great significance to do further studies in this area in China.We selected 26 individuals infected with HIV-1, and 23 with HIV-1/HCV-coinfected. Firstly, T lymphocyte subpopulation CD4~+T cells and CD8~+T cells were isolated from human PBMCs using immunomagnetic microbeads. Secondly, frequencies of IFN-γsecreting cells in CD4~+T, CD8~+T lymphocytes and PBMCs from 49 patients were assessed by stimulation with a peptide pool containing 12 overlapping peptides in HIV-1 P24 via assay of ELISPOT. Finally we analyzed and compared the respective influence of CD4~+and CD8~+T lymphocytes to HIV-1 specific cell-mediated immunity responses. Meanwhile, cytokines in plasma such as IFN-γ, interleukin (IL)-4, IL-6, IL-7, IL-12, IL -21 were measured using enzyme-linked immunosorbent assay (ELISA) in order to analyze the correlation among these cytokines and infectd with HIV-1 and HCV.The main research contents and results are as follows:1. Study on the HIV-1 antigen specific CD4~+/CD8~+T lymphocyte immune responses was carried out among 49 patients, which consisted of 26 HIV-1–monoinfected and 23 HIV-1/HCV-coinfected patients, and all of whom had received highly active antiretroviral therapy (HAART). It turned out that frequencies of HIV-1 antigen specific CD4~+T lymphocyte responses in HIV-1–monoinfected group were significantly lower than those responses of CD8~+T lymphocytes ( F=4.592 , P=0.037) and PBMCs ( F=5.436 , P=0.025 ) , but the differences between the responses of CD8~+T lymphocyte and PBMC were not obvious ( F=0.001 , P=0.970 ) . Frequencies of HIV-1 antigen specific CD4~+T ( Z= -2.432 , P=0.015 ), CD8~+T ( Z= -1.996 , P=0.046 ) lymphocyte and PBMC ( Z= -2.306 , P=0.021 ) responses in HIV-1/HCV-coinfected group were dramatically lower than those of HIV-1–monoinfected group.2. As is shown by the analysis of the correlations among frequencies of HIV-1 antigen specific CD4~+T/CD8~+T lymphocyte, the counts of blood CD4~+T /CD8~+T, there were no correlations between the frequencies of HIV-1 specific cell responses and the counts of blood CD4~+T , CD8~+T in all 49 HIV-1–monoinfected and HIV-1/HCV–coinfected individuals.3. We detected plasma viral load of the subjects, and found that: in HIV-1-monoinfected group the frequencies of HIV-1 antigen specific CD4~+T, CD8~+T lymphocyte, PBMC responses between the patients with viral load <40 copies /mL were higher than those with viral load >40 copies/mL, but the differences were not significant (P=0.166, 0.187, 0.400). Viral load <40 copies /mL, the frequencies of HIV-1 antigen specific immune responses were higher in HIV-1-monoinfected group than those in HIV-1/HCV-coinfected group ( P=0.006, P=0.026, P=0.021), while with viral load >40 copies/mL the differences are not significant ( P=0.268, P=0.376 , P=0.507 ).4. We measured the concentration of IFN-γ, IL-4, IL-6, IL-7, IL-12, IL-21 in plasma , using ELISA, and found that : the differences between HIV-1–monoinfected group and HIV-1/HCV–coinfected group were not obvious ; the concentration of IL-4, IL-12 and IFN-γin both groups were significantly higher than healthy control group ( P=0.000 ), while IL-6 ,IL-21 were obviously lower than healthy control group ( P=0.000 ).The concentration of IL-7 in HIV-1-monoinfected group were obviously higher than healthy control group ( P=0.049 ),while the concentration of IL-7 in HIV-1/HCV-coinfected group were higher than healthy control group,but the difference were not obvious ( P=0.365 ).Conclusions:1. HIV-1 specific CD4~+T cell immune response exist in HIV-1 infected individuals, which is significantly lower than CD8~+T cells;2. In HIV-1/HCV-coinfected group, the HIV-1 antigen specific cellular immune response was down-regulated by HCV infection, which needs further investigation whether this is one of the reasons of the poor efficacy of HAART on HIV-1/HCV-coinfected individuals. 3. In HIV-1/HCV-coinfected group, the secretion of IL-4, IL-6, IL-7, IL-12, IL-21 and IFN-γin vivo were significant impacted by HIV-1 infection compared with HCV infection.