Abstract: Genes encoding five immunodeterminant protein antigens of the leprosy parasite Mycobacterium leprae have been isolated. The gene encoding the M. leprae 65kD antigen was sequenced and a lambda gt11 gene sublibrary was constructed with fragments of the gene. Recombinant DNA clones producing specific antigenic determinants were isolated using monoclonal antibodies and the sequences of their insert DNAs were determined with a rapid primer extension method. Amino acid sequences for six different epitopes of the M. leprae protein were elucidated. A peptide containing sequences for one of these epitopes, which is unique to M. leprae, was synthesized and shown to bind the appropriate monoclonal antibody; The approach described here can be used to elucidate rapidly protein epitopes that are recognized by antibodies or T cells. In addition, the well-characterized M. leprae antigens can be used in prevention, diagnosis and treatment of leprosy.

Abstract: Systems are provided for the dual purpose of cloning genes using antibodies as probes and isolating unknown proteins encoded by cloned DNA. The method employs a vector derived from phage which is used in combination with a high frequency lysogenic host. The vector is further characterized by having an inducible promoter regulating expression of a gene into which the foreign DNA may be introduced to produce a fused protein, and controlled induction of the prophage with rapid increase in copy number and high level transcription of foreign DNA. The technique is exemplified with a specific lambda phage construct in conjunction with the .beta.-galactosidase structural gene lacZ.

Abstract: Yeast cells that express rennin or prorennin are used in disrupted cellular form to clot milk without the need for purification of the rennin or prorennin. Cheese making is simplified and reduced in cost by the avoidance of substantial purification techniques to obtain rennin or prorennin from living cells which produce these materials.

Abstract: A DNA segment containing a GAL1 promoter linked to a gene other than the galactokinase gene for directing the expression of the gene within a yeast cell.