CD5+ B-lymphocytes are as dependent on T-helper cells and as responsive to T-suppressor cells in pokeweed mitogen-stimulated activation as conventional CD5- B-lymphocytes.

Pokeweed mitogen (PWM)-stimulated cultures were established with varying numbers of CD4+ or CD8+ cells and CD5+ immunoglobulin-secreting cells were subsequently identified using a combination of haemolytic plaque formation and rosetting with immunobeads coated with anti-Leu-1. It was found that CD5+ and CD5- B-cells required similar numbers of CD4+ cells for half-maximum plaque-forming cell (PFC) induction and that 50% suppression of both CD5+ and CD5- PFC occurred with similar numbers of CD8+ cells. Suppression of both CD5+ and CD5- PFC could occur when T-helper signals were supplied by a PWM-stimulated culture supernatant, indicating that both subsets could be directly suppressed by CD8+ cells rather than by indirect suppression of T-helper cells. It is concluded that CD5+ B-cells are as responsive to T-regulatory influences as conventional CD5- B-cells.