Human T-cell clones with reactivity to Mycobacterium leprae as tools for the characterization of potential vaccines against leprosy.

T-cell clones with the T4 phenotype were established from patients with tuberculoid leprosy. The antigen reactivity of these clones ranged from stringent specificity for Mycobacterium leprae to broad cross-reactivity with other mycobacteria. Killed M. leprae had a weak stimulatory capacity which could be enhanced by ultrasonication. Among the three candidate antileprosy vaccines, M. leprae, M. bovis BCG, and the ICRC (Indian Cancer Research Center) strain, the last was superior in stimulating cross-reactive T4 clones. This finding argues for a differential masking of similar or identical membrane antigens in various mycobacterial species. T-cell clones with defined reactivity patterns for mycobacterial antigens could be helpful tools for the characterization of an antileprosy vaccine.