Hapten-specific stimulation of secondary B cells independent of T cells.

Treatment of spleen cell suspensions from immunized mice with anti-theta serum and complement before transfer to nonimmune irradiated recipients reduced the degree of in vitro stimulation by hapten-homologous carrier complexes by 90%, but did not decrease at all the number of isolated precursor cells stimulated by hapten on heterologous carriers. Thus, secondary B cells can be stimulated by low concentrations of multiply substituted hapten-carrier complexes in the apparent complete absence of specific T cells.