Studies on the adjuvant effect of Bordetella pertussis vaccine to sheep erythrocytes in the mouse. I. In vitro enhancement of antibody formation with normal spleen cells.

The adjuvant effect of Bordetella pertussis vaccine (PV) on the antibody response to sheep erythrocytes (SRBC) has been studied in vitro with the Mishell-Dutton immunization technique. The addition of PV to cultures of spleen cells obtained from normal non-immunized mice markedly enhanced the plaque-forming cell response to SRBC. The greatest enhancement was evident at 24 hr of culture. PV was also shown to enhance the antibody response of spleen cells that had been depleted of either T lymphocytes or adherent cells, presumably macrophages. In addition, it was found that PV, per se, released into the culture medium a soluble cell-free component(s) that contributed significantly to adjuvanticity. The results suggest that at least one of the ways that PV enhances the in vitro immune response to SRBC is by direct stimulation of precursors of antibody-forming cells.