Effect of Plasmodium yoelii YM Infection on Vaccination with 19 kDa Carboxylterminus of the Merozoite Surface Protein 1 (MSP1_(19))

摘要

We have previously demonstrated the ability of malaria parasites to interfere with specific immune responses. CD4 T cells specific to parasite antigens, but not CD4 T cells specific to an irrelevant antigen, ovalbumin (OVA), are de- leted via apoptosis during malaria infection. It is of interest, therefore, to investigate the immune responses that developed following vaccination with the 19 kDa carboxylterminus of the merozoite surface protein 1 (MSP119) in mice that had previ- ously experienced malaria infection. In this study, pre-exposure of mice to Plasmodium yoelii elicited native anti-MSP119 an- tibody responses, which could be boosted by vaccination with recombinant MSP119 . likewise, infection of MSP119-primed mice with Plasmodium yoelii ( P . yoelii) led to an increase of anti-MSP119 antibodies. MSP119 vaccination of malaria pre- exposed mice or immunization by infection/cure of MSP119-primed mice enabled the mice to survive challenge infection, with the former group having slightly lower parasitaemia. The data suggest that exposure to malaria infection primes a natural im- mune response which can be boosted by vaccination. This information is relevant to the development of a vaccine for use in individuals living in malaria-endemic areas.