Kulachart JangpatarapongsaJeeraphat SirichaisinthopJetsumon SattabongkotSornchai Looareesuwanศรชัย หลูอารีย์สุวรรณMarita Troye-BlombergRachanee UdomsangpetchMahidol University. Faculty of Tropical Medicine. Department of Clinical Tropical Medicine2016-02-052021-08-302016-02-052021-08-302016-02-052004https://repository.li.mahidol.ac.th/handle/20.500.14594/63376Joint International Tropical Medicine Meeting 2004: Ambassador Hotel, Thailand 29 November-1 December 2004: abstract. Bangkok: Faculty of Tropical Medicine, Mahidol University; 2004. p.201.Immunity induced by P. vivax during acute infection leads to memory T cells recruitment of which will be activated during subsequent infection. This study therefore aims to verify the level of memory T cells during acute and convalescent periods. Memory T cells are recognized by the surface molecules CD45RO+ CD27+ as an early stage and CD27- as a mature stage. The results showed significant [P<0.01] increase of mean percentage of CD4+ memory T cells during acute infection when compared with those either from healthy donors and immune villagers. The P. vivax-induced memory T cells were maintained at high level until 60 days post treatment. The mean percentage of CD8+ memory T cells was also significantly higher during acute infection until 60 days post treatment. Interestingly, the CD8+ memory T cells was stably maintained at high level among the non-acute malaria immune villagers in contrast to the low level CD4+ memory T cells in the same immune villager group. These results suggest that memory T cells particularly CD8+ phenotype-play role in the development of naturally acquired protection against P. vivax infection. The ongoing study will investigate further whether or not the protection is mediated by the memory T cells of ab-phenotypeengMahidol UniversityMalariaPlasmodium VIVAXProceeding Poster