Functional heterogeneity of CD4-positive T-cell subsets: the correlation between effector functions and lymphokine secretion is limited.

Several effector functions and the lymphokine secretion pattern of 30 antigen-specific CD4+ T-cell clones have been investigated. The clones were generated directly by limiting dilution cloning of nylon wool-purified T-cells obtained from KLH immunized BALB/c mice and avoiding an initial bulk culture phase. Using this approach the CD4+ T-cell clones were grouped into helper and nonhelper subsets. Among the helper subset, clones which helped B-cells for specific antibody production by either cognate or noncognate recognition were identified. Some but not all of these helper clones fitted into the Th1 and Th2 scheme, if the lymphokine secretion pattern was evaluated. Among the nonhelper subset CD4+ clones which killed activated APC in a MHC class II-restricted and antigen-specific manner were identified. In addition, one clone which suppressed B-cell antibody production mediated by helper clones was found. However, neither the suppression of antibody responses nor the inability of the nonhelper clones to help B-cells is due to the killing of B-cells. Various attempts were made to convert nonhelper into helper clones and helper into killer clones, without success. Thus, the functional properties of these clones are stable traits and not convertible by varying the experimental conditions.