Regulation of the immune responses to a streptococcal antigen by helper and suppressor functions in man.

Natural sensitization of human lymphocytes to a SA, isolated from Streptococcus mutans, has been investigated by stimulating T-lymphocytes in vitro with the streptococcal antigen. Helper or suppressor activity released by the lymphocytes was then tested for anti-DNP antibody-forming cells. A differential dose-response of about 1000 ng of SA was found between the specific helper function of HLA DRw6 and DR4 lymphocytes. Specific suppressor activity showed a reciprocal relationship to helper activity. Depletion of suppressor cells, by killing these with the monoclonal T8 antiserum and complement, resulted in loss of suppressor, but increased dose response in helper function. Conversely, helper-cell-depleted cultures showed a loss of helper and increased dose response in suppressor function. The results suggest a reciprocal controlling function of helper and suppressor cells. The HLA-DR linked antigens might be related to significant shifts in the dose response of helper cells.