Tandem use of PCR and synthetic peptides to map helper T-cell epitopes on 27-kDa sexual stage antigen of Plasmodium falciparum

Document Type

Journal Article

Publication Date



Peptide Research






Monoclonal antibodies recognizing two overlapping linear epitopes (amino acid residues 10 to 25) on the 27-kDa sexual stage antigen of Plasmodium falciparum (Pfg27) effectively reduce the infectivity of the parasites to mosquitoes. Although malaria transmission-blocking immunity is largely antibody-mediated, T cells play critical roles in the regulation of antibody secreting B cells. In order to facilitate the development of a malaria transmission-blocking subunit vaccine, studies were undertaken to map epitopes on Pfg27 recognized by T-helper lymphocytes. Pfg27-specific T-cell hybridoma clones were produced from Pfg27-immunized BALB/c (H-2(d)) and C57BL/6 (H-2b) mice, and used in studies to map antigenic determinants using PCR-generated Pfg27 gene fragments express'ed in E. coli and synthetic peptides based on the Pfg27 sequence. We identified and mapped five distinct T-cell epitopes that tire recognized by major histocompatibility complex (MHC) class II-restricted T-cell hybridoma clones. A single peptide (21 residues) was shown to contain two tandem or partially overlapping epitopes recognized by T-cell hybridomas in the context of I-A(d) and I-Ab, respectively. Synthetic peptides representing epitopes recognized by T-cell hybridoma clones elicited strong IgG responses in immunized mice, suggesting that T-cells of the helper phenotype were stimulated in vivo by these peptides. These studies represent the first detailed T-cell epitope analysis of a malaria sexual-stage antigen.

This document is currently not available here.