CHARACTERISTICS OF THE PROTECTIVE RESPONSE OF BALB/C MICE IMMUNIZED WITH A PURIFIED PLASMODIUM-YOELII SCHIZONT ANTIGEN

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 54  (3) , 609-616
Abstract
The reponse of BALB/c mice to immunization with a 230,000 MW protective antigen purified from the blood stages of P. yoelii was analyzed. The protective response to immunization was adjuvant-dependent, and saponin was the most effective adjuvant tested. The i.p. route was superior to the s.c. route for protective immunization. Maximal protection was achieved using 2 immunizations with > 12.5 .mu.g of antigen plus saponin, but even under these conditions challenge infection developed normally for 5 days, followed by the appearance of crisis forms and rapid clearance of parasites. Effective immunization induced high antibody titers, but serum from immunized mice was not protective on passive transfer. Hyperimmune serum from mice recovered and rechallenged with live P. yoelii was protective on passive transfer, even though the titer of antibody specific for the 230,000 MW antigen in this serum was the same as that in the serum from mice immunized with the purified antigen. The 230,000 MW antigen may provide protection against P. yoelii via the cell-mediated immune effector pathway desribed by Playfair et al. (1979), and hyperimmune serum contains protective antibodies specific for P. yoelii antigens other than the 230,000 MW antigen.