The role of CD4 + T cells in the protective immune response to Plasmodium chabaudi in vivo

Abstract

CD4 + T cells are an essential component of the protective immune response to Plasmodium chabaudi. In order to determine whether the presence of CD4 + T cells is necessary throughout a primary infection for a protective immune response to develop mice were depleted of their CD4 + T cells in vivo by treatment with specific antibodies. Removal of CD4 + T cells during the acute phase of infection renders mice incapable of clearing their infection. In contrast, removal of CD4 + T cells after this time did not affect their ability to control their parasitaemia. The ability to control parasitaemia correlated with appearance of malaria-specific IgG antibodies. Our data, therefore, suggest a mechanism requiring the presence of CD4 + T cells during the acute pre-IgG period. Later, after IgG has been produced, this mechanism is no longer required.