EXPANSION OF THE CD4-,CD8- GAMMA-DELTA T-CELL SUBSET IN THE SPLEENS OF MICE DURING NONLETHAL BLOOD-STAGE MALARIA

Splenic gammadelta T cells (CD4 , CD8 ) increased more that 10-fold up on resolution of either Plasmodium chabaudi adami or P c. chabaudi inf ections in C57BL/6 mice compared to controls. Similarly, a 10- to 20-f old expansion of the gammadelta T cell population was observed in beta 2-microglobulin deficient (beta2-m0/0) mice that had resolved P c. ada mi, P c. chabaudi or P yoelii yoelii infections. In contrast, increase s in the number of splenic alphabeta T cells in these infected mice we re only two to three-fold indicating a differential expansion of the g ammadelta T cell subset during malaria. Because nucleated cells Of bet a2-M0/0 mice lack surface expression of major histocompatibility compl ex class I and class Ib glycoproteins, our findings suggest that antig en presentation by these glycoproteins is not necessary for the increa sing number of gammadelta T cells. Our observation that after resoluti on of P c. adami malaria, C57BL/6 mice depleted of CD8+ cells by monoc lonal antibody treatment had lower numbers of gammadelta T cells than untreated controls suggests that the demonstrated lack of CD8+ cells i n beta2-M0/0 mice does not contribute to the expansion of the gammadel ta T cell population during non-lethal malaria.