[Roles of T cell subsets in the protective immunity of mice against Plasmodium yoelii].

BALB/c mice which had developed protective immunity against Plasmodium yoelii (P. y.) challenge were injected with anti-CD4 or anti-CD8 monoclonal antibody, and were then challenged again with P. yoelli. No impairment of protection was observed. CD8+T cells obtained from spleens of these mice were transferred to BALB/c nude mice and induced partial protection, while transfer of CD4+T cells did not so. In P. yoelli-mouse model, the parasites invaded reticulocytes in the early infection, and the infected reticulocytes could be recognized and attacked by sensitized CD8+T cells. In late infection when P. yoelli also invaded mature erythrocytes, the protective effect of CD8+T cells decreased and the main role of protection was played by antibodies.

Construction and screening of Plasmodium falciparum cDNA library.

The HAINAN isolate of Plasmodium falciparum FCC1/HN was cultured in vitro in large quantities. The total parasite mRNA was purified and reverse transcribed into cDNA. The cDNA fragments were inserted into lambda gt11 to construct a P. falciparum FCC1/HN erythrocytic stage cDNA library. Inhibitory monoclonal antibodies (McAbs) M26-32, F6-C2, and F6-D3 were used to screen the cDNA library expressed in E. coli. A total of 27 positive clones were found to react with M26-32 alone and 34 clones with both M26-32 and F6-C2. These expressed proteins may be candidates for use in malaria vaccine.