ASSOCIATION BETWEEN CELLULAR-RESPONSE (IL-4) TO RESA PF155 AND PROTECTION FROM CLINICAL MALARIA AMONG PAPUA-NEW-GUINEAN CHILDREN LIVING IN A MALARIA ENDEMIC AREA/

A prospective study in 207 children aged 0.5-15 years was carried out to examine the relationship between cellular responses to Plasmodium f alciparum ring-infected erythrocyte surface antigen (RESA) and malaria infection and morbidity. The prevalence of lymphoproliferative respon se to RESA was 13%, IFN-gamma prevalence was 40% and IL-4 prevalence w as 22%. Only the IFN-gamma, response to RESA increased significantly w ith age. When proliferation or stimulation of either cytokine was used to assess T-cell activation the overall frequency of responders incre ased to 55%. The proliferative and IFN-gamma response to RESA were pos itively associated. Although there was no association between any of t he CMI responses to RESA and concurrent morbidity the prevalence of IL -4 response to RESA was significantly lower in children who experience d clinical malaria in the following year. These results coupled with o ur earlier darn showing a negative relationship between humoral respon ses to RESA and malaria morbidity support the inclusion of RESA in a s ubunit vaccine against malaria.