Functional analysis of the defective T cell regulation of the antigen-specific PFC response in SLE patients: differentiation of suppressor precursor cells to suppressor effector cells.

The investigation described here is concerned with the T cell regulation of the antigen-specific antibody response which has been studied in patients suffering from systemic lupus erythematosus (SLE). Apart from the fact that T helper cell activity was found to be less efficient, it appeared that the peripheral blood leucocytes (PBL) of patients in an active stage of the disease did not contain the suppressor precursor cells, which functions as the target cell for the inductive signal of T mu+ suppressor inducer cells. The absence of the suppressor precursor cells in SLE patients coincided with the absence of T gamma+ suppressor effector cells. Characterization of the (post-thymic) precursor cells (derived from normal donors) with the aid of monoclonal antibodies of the OKT series and several other markers pointed out that this population contains OKT4+ as well as OKT8+ cells. Further experiments demonstrated that the cells are capable of rosetting with autologous erythrocytes, and do not bear Fc receptors for IgM or IgG. Considering the various findings as a whole the conclusion is warranted that the post-thymic suppressor precursor T cell can differentiate into a suppressor effector cell only after interaction with T suppressor inducer cells.