Potentiation of Cell-Mediated Immune Responses Directed against P. Falciparum Sporozoite Peptide Vaccine by Immunomodulators

The development of genetically engineered subunit vaccines has renewed and intensified efforts to immunize third world populations against currently uncontrolled diseases including malaria; however, the success of such vaccines will depend in large part upon efforts to enhance their immunogenicity. It is likely that subunit vaccines will require potent adjuvants in order to be effective. While considerable work has been aimed at enhancing antibody responses to peptide antigens, little is know regarding the potentiation of antigen specific cell-mediated immune responses. We have utilized a delayed type hypersensitivity (DTH) model to investigate cell-mediated immune responses, including those parameters which affect the induction, magnitude and duration of responsiveness. We examined the potency of R32tet32, a subunit vaccine directed against the sporozoite stage of Plasmodium falciparum, to induce and elicit DTH responses in mice and found that these responses were potentiated significantly through the use of selected lymphokines and immunomodulators.