|Budget Amount *help
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,000,000 (Direct Cost: ¥1,000,000)
HLA class II antigens play an essential role in the immune response by interacting with regulatory T cells. At least three distinct HLA class II antigens, designated HLA-DR, -DQ, and - DP,exist and are expressed simultaneously on the same cells. Therefore, it is extremely difficult to examine the role of each class II antigen in the immune response. We introduced alpha and beta chain genes of one of DR, DQ, and DP antigens into murine L cells and obtained transformants expressing DR, DQ, or DP antigens individually. Applying these transfectants to mixed lymphocyte reaction (MLR) and the antibody-production in MLR, we assessed the function of DR, DQ, and DP antigens individually. In MLR, the order of stimulating abilities appeared to be DR>DQ>DP antigen-expressing transformants. As the stimulating ability in MLR did not correlate with the antigen-dose, it seems likely that the different responsiveness in MLR did not reflect the difference of antigen-dose but reflected the size of T cell pool responding each of DR, DQ, and DP antigens.
MLR caused by these transformants were blocked by monoclonal antibodies against each class II antigens, indicating that these MLR were elicited by class II antigens expressed on transformants. Next, we assessed the role of class II antigens in the IgG and IgM-production in MLR. Similar to the results of MLR, the amount of antibody-production caused by the transformants was DR>DQ>DP-expressing transformants in both IgG and IgM. Mixing experiments of transformants showed that no suppressor T cells was induced by any transformants.
Taken together, these results indicate that the different responsiveness to transformants in both MLR and the antibody-production is attributable to the different sizes of T cell clone pools responding to each class II antigen.