Poster Presentation The Australasian Society for Immunology 2017 Annual Scientific Meeting

An examination of the persistence and immunogenicity of Plasmodium blood-stage parasites following commencement of chemoprophylaxis with delayed death antimalarial drugs (#311)

Leanne Low 1 , Aloysious Ssemaganda 1 , Danielle Stanisic 1 , Michael Good 1
  1. Griffith University, Southport, QUEENSLAND, Australia

Malaria vaccine research has generally focused upon single parasite derived proteins for the development of a subunit vaccine. However, many of these proteins are highly variable and are unable to elicit protective responses to multiple strains. A vaccine approach utilising the whole parasite is advantageous in containing multiple parasite antigens, including those that are conserved between parasite strains.  Adopting an infection and drug cure (IDC) immunisation approach, blood-stage whole parasites were administered alongside treatment with the delayed death causing antimalarial drugs, doxycycline and azithromycin. This approach was investigated in C57BL/6 and BALB/c strains of mice receiving IDCs with either P. chabaudi AS or P. yoelii YM. In both mouse strains, one IDC with P. chabaudi AS or P. yoelii YM elicited protection from homologous challenge. Protection was enhanced with a further two IDCs, compared to a single IDC. Heterologous protection was also observed in mice receiving three IDCs of P. chabaudi; however, there was minimal to no protection in the P. yoelii model. Cell mediated immune responses were observed in both models, while humoural mediated immunity was observed in the P. yoelii model. Results to date suggest protection is primarily mediated through a TH1 response, with the presence of IFN-gamma and IL-2 production being observed in both mouse models. Current work aims to further elucidate the mechanisms of immunity and investigate the use of a slow drug release to replace repeated treatment.