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Background & Objective: Few studies concerning the effects of Opioid drugs on the function of immune system have been conducted and conflicting results have been reported. This study evaluates the in-vitro immune responses of drug abusers and investigates the pattern of production of IFN-? and IL-10, which represents the subsets of CD4+T-helper cells. Materials & Methods: Blood samples were taken from healthy drug addicted volunteers. Blood samples were also taken from healthy individuals with no history of drug abuse as control. Cell culture was performed in whole blood culture assay. Diluted blood samples were stimulated with phytohemagglutinin (PHA) and lipopolysaccharide (LPS) and the supernatants were collected to measure the Cytokine production. Results: The results demonstrated that a significant decrease in IFN-? production and increase in IL-10 production in Heroin addicts, whereas the production of these Cytokines in Opium addicts was not significant different from those in control group. Conclusion: The results indicated a significant decrease in mitogenic responsiveness of T-cells in Heroin addicts relative to control group, whereas mitogenic responsiveness of T-cells in Opium addicts was not significantly different from control group.

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Background&Objective: Both CD4+ type 1 helper (Th1) cells and CD8+ T cells play effective roles in protection against Mycobacterium tuberculosis infection. MPB51, a major mycobacterial secreted protein, induces humeral and cellular immune responses against mycobacterial infection. In addition, DNA vaccine encoding MPB51 can induce cellular immune responses and protective immunity upon challenge with M.tuberculosis. This study address to identify T-cell immunodominant epitopes on MPB51 in BALB/c mice. Materials&Methods: We cloned DNA encoding MPB51 molecule in pCI plasmid. After constructing MPB51 DNA-covered gold cartridge, BABL/c mice were immunized by using a gene gun system. Two weeks after the last immunization, the immune spleen cells were cultured in response to synthetic overlapping library peptides covering the mature MPB51 sequence or medium alone. Intracellular and cell culture supernatant gamma interferon (IFN-) production was analyzed by using flow cytometry and ELISA, respectively. Results: The findings of present study indicate that DNA vaccination can course strong mmune response only against the peptides contain 21-40 aminoacids. Further analysis with a computer – assisted algorithm permitted the identification of nine aminoacids of (P24-32) as immunodominant CD8+ T cell epitope. Conclusion: This study proved than the MHC class I-peptide (H2-Dd-P24-32) complex is recognized by (IFN-)–producing CD8+ T cells. We observed by using T-cell subset depletion that CD8+ T cells are the only P24-32-responded T-cells in BABL/c mice. The data obtained are useful for identifying cellular immune responses against TB and for designing a new vaccine against M.tuberculosis infection.