A time study of the requirement for carrier-specific helper cells in the response of mice to dinitrophenylated keyhole limpet hemocyanin.

ABSTRACT

The anti-hapten response of spleen cells from mice primed with hapten-carrier (dinitrophenylated keyhole limpet hemocyanin) was decreased by depletion of T cells during the first four days after secondary antigenic stimulation, but was unaffected when the T cells were depleted on day 5. The response of cultures that were depleted of T cells prior to secondary antigenic stimulation was restored by addition of carrier-primed cells during the first two days of culture, partially restored on day 3, but not at later times. Thus, T cells were required only at about day 4 of a secondary response to a T-dependent antigen that peaked on day 8. Autoradiography experiments showed that the frequency of antigen-binding cells increased with time regardless of the presence of T cells in the cultures. We conclude that helper T cells are not required for B cell proliferation, but are required for the differentiation of B cells to antibody-secreting cells.