The effect of a proline-rich polypeptide (PRP) on the humoral immune response. II. PRP induces differentiation of helper cells from glass-nonadherent thymocytes (NAT) and suppressor cells from glass-adherent thymocytes (GAT).

Normal mice given thymocyte subpopulations preincubated with a proline-rich polypeptide (PRP) and immunized with SRBC show enhanced or suppressed humoral immune response measured by the number of plaque-forming cells (PFC). PRP induces differentiation of cells exhibiting helper or suppressive function from NAT and GAT respectively. Moreover, it was demonstrated that PRP-induced helper cells lost their activity after treatment with anti-Lyt 1,1 and the PRP-induced suppressor cells after treatment with anti-Lyt 2,1 monoclonal antibodies.