Pan DR binding sequence provides T-cell help for induction of protective antibodies against Plasmodium yoelii sporozoites.

Pan-DR epitope (PADRE) peptides have demonstrated the capacity to deliver help for antibody responses in vivo. They were also found, fortuitously, to be able to provide significant helper T-cell activity in vivo. This suggested that linear constructs, containing the PADRE epitope, might be as efficient at generating an immune response as large multivalent antigens. Plasmodium falciparum and P. yoelii PADRE constructs were capable of inducing a high titre IgG antibody response that recognized intact sporozoites. We now report that these antibodies can inhibit sporozoite invasion of hepatocytes in vitro and that mice immunized with the PyCSP-PADRE linear construct were protected when challenged with P. yoelii sporozoites.