Detection and characterization of a lambda gt11 recombinant clone of M. leprae that expresses an antigenic determinant of a 64-kDa protein.

A genomic library of Mycobacterium leprae in the expression vector lambda gt11 was screened with rabbit polyclonal hyperimmune antiserum elicited with a sonicated extract of M. leprae. Numerous reactive clones were isolated by this immunoscreening, indicating a broad antibody response of the rabbit. None of the recombinant clones was reactive with monoclonal antibodies to the previously well-characterized M. leprae recombinant clones. One of the clones isolated, clone A, encoded a large, 132-143-kDa beta-galactosidase fusion protein expressing an epitope of M. leprae. Monospecific antibodies eluted from this fusion protein reacted on Western blots with a 64-kDa M. leprae protein. The DNA of this clone was shown to be distinct from the gene encoding the well-characterized immunodominant 65-kDa protein by DNA hybridization. We have identified a new lambda gt11 recombinant clone encoding a fusion protein with a 64-kDa protein. This protein is recognized by the humoral immune response of the rabbit in response to a challenge with an M. leprae cell extract.