Adjuvant effect of Bordetella pertussis vaccine to sheep erythrocytes: enhancement of antibody formation by using subcutaneous administration of adjuvant and antigen.

The subcutaneous route (s.c.) was used to study the adjuvant effect of Bordetella pertussis vaccine (pv) on the primary antibody response to sheep erythrocytes. The reasons for using the s.c. route are discussed. PV, besides enhancing the hemagglutinin response, also markedly increased the number of plaque-forming cells in the draining lymph nodes. A heated preparation of PV was tested and found to possess significant adjuvant activity. Interestingly, the enhancement occurred in the absence of marked enlargement of the lymph nodes, which was characteristic of the unheated preparation. In addition, a crude solubilized cell-free preparation of PV was tested and also found to possess significant adjuvant activity. The activity was only partially abolished by heat. Hence, it was concluded that both heat-labile as well as heat-stable factors contributed to the adjuvanticity of PV. The studies also support the view that the draining lymph nodes represent a principal locus of action of PV and that the s.c. route of administration of adjuvant and antigen provides a suitable model for studying and assaying the adjuvanticity of PV.