Genetic restriction of the murine humoral response to a recombinant Plasmodium vivax circumsporozoite protein

The antibody response of inbred and congenic strains of mice immunized with a recombinant Plasmodium vivax circumsporozoite protein was investigated. Only mice of the H‐2k and H‐2a haplotypes developed antibodies that react with P. vivax sporozoite in an indirect immunofluorescence assay and with the recombinant protein in enzyme‐linked immunosorbent assay. Congenic recombinant strains were used to map Ir gene control to the I‐Ak locus. A similar pattern of genetic restriction was found when congenic strains were immunized with a carrier‐free synthetic peptide corresponding to the repeat region of the P. vivax circumsporozoite protein. The results suggest that the ability of T helper cells to recognize a T cell epitope(s) in the repeat region of the P. vivax circumsporozoite protein is genetically restricted.