T-Cell Mediated Inhibition of Liver-Stage Development Assay

Most studies of the T-cell response to Plasmodium-infected hepatocytes have been done with the rodent parasites, P. yoelii and P. berghei. Early experiments showed that mice immunized with irradiated sporozoites of P. berghei and devoid of antibodies after a long-term treatment with anti-IgM antibodies resisted a live sporozoite challenge (1 ), suggesting that T cells by themselves were able to confer protection. Further transfer of both CD8⁺ and CD4⁺ T-cell clones specific for T epitopes from P. yoelii or P. berghei circumsporozoite or SSP-2 protein confirmed that these T cell populations could confer protection against a sporozoite challenge (2 -6 ). However, these experiments provided indirect evidence that T cells inhibit parasite development in hepatocytes.