Mapping of T cell epitopes using recombinant antigens and synthetic peptides

Two complementary approaches were used to determine the epitope specificity of clonal and polyclonal human T lymphocytes reactive with the 65-kd antigen of Mycobacterium leprae. A recombinant DNA sublibrary constructed from portions of the 65-kd gene was used to map T cell determinants within amino acid sequences 101-146 and 409-526. Independently, potential T cell epitopes within the protein were predicted based on an empirical analysis of specific patterns in the amino acid sequence. Of six peptides that were predicted and subsequently synthesised, two (112-132 and 437-459) were shown to contain human T cell epitopes. This corroborated and refined the results obtained using the recombinant DNA sublibrary. Both of these regions are identical in M. leprae and M. tuberculosis and are distinct from the known B cell epitopes of the 65-kd protein. This combination of recombinant DNA technology and peptide chemistry may prove valuable in analysis of the cellular immune response to infectious agents.