Screening gene expression libraries for epitopes recognized in Mycobacterium leprae by mouse T cells

Parasite expression libraries have so far been screened with antibodies, DNA probes or T cell clones. Immunity to many parasites, such as Mycobacterium leprae, is largely mediated by T cells, and so the screening of such libraries for T cell epitopes is an important step toward the development of effective vaccines and diagnostic reagents. A new method for screening of λgt11 libraries with uncloned T cell populations is presented here, which takes advantage of the fact that the recombinant proteins contain β‐galactosidase as their leader peptide; this allows them to be semipurified by means of anti‐β‐galactosidase antibodies coated on the bottom of microtiter plate wells, within which a proliferation assay can then be carried out. Optimum conditions for the assay were determined, using the M. leprae 18‐kDa antigen as a test antigen.