Immunity to Plasmodium falciparum malaria sporozoites by somatic transgene immunization.

Immunity against the human malaria parasite Plasmodium falciparum was induced using somatic transgene immunization, a method to effectively target B lymphocytes in vivo. A single inoculation of plasmid DNA containing an immunoglobulin heavy-chain gene coding in the complementarity-determining region 3 for three repeats of the sequence Asn-Ala-Asn-Pro (NANP), a B-cell epitope of P.falciparum sporozoites, induced antibodies against NANP in all mice. A booster with an antibody antigenized with the NANP peptide, or challenge with P. falciparum sporozoites, demonstrated the establishment of immunologic memory. Immunity to a parasite antigen can be induced by exploiting mechanisms in which B lymphocytes are both the source of the immunogen as well as the effector mechanism of immunity. The results indicate that somatic transgene immunization is a potential approach for vaccination against foreign pathogens.