M. Tsuji et al., GAMMA-DELTA T-CELLS CONTRIBUTE TO IMMUNITY AGAINST THE LIVER STAGES OF MALARIA IN ALPHA-BETA T-CELL-DEFICIENT MICE, Proceedings of the National Academy of Sciences of the United Statesof America, 91(1), 1994, pp. 345-349
The functional role of gammadelta T cells (expressing the gammadelta h
eterodimeric T-cell receptor for antigen) in infectious diseases remai
ns largely unknown. We have therefore attempted to define the possible
role of these T cells in the immune response against the various deve
lopmental stages of malaria parasites. For this purpose, we monitored
the immune response and the development of liver and blood stages of P
lasmodium yoelii, a rodent malaria parasite, in immunized and nonimmun
ized alphabeta T-cell-deficient and gammadelta T-cell-deficient mice.
Immunization of alphabeta T-cell-deficient mice with irradiated sporoz
oites induced an immune response that significantly inhibited the deve
lopment of the parasite's liver stages. This inhibitory immune respons
e was abolished by an antibody-mediated transient in vivo depletion of
gammadelta T cells. Two gammadelta T-cell clones were derived from ma
laria-immunized alphabeta T-cell-deficient mice. The adoptive transfer
of one of these gammadelta T-cell clones to normal mice inhibited the
development of liver stages, following sporozoite inoculation. These
results provide evidence for gammadelta T-cell-mediated protective imm
unity against parasites, in the absence of alphabeta T cells. As for t
he blood phase of the infection, both normal mice and gammadelta T-cel
l-deficient mice cleared the blood stages of the nonlethal strain of P
. yoelii, while alphabeta T-cell-deficient mice failed to control the
parasitemia.