HLA class-II-restricted Mycobacterium leprae-reactive T-cell clones from leprosy patients established with a minimal requirement for autologous mononuclear cells.

This report describes an effective method for the cloning of Mycobacterium leprae-reactive T lymphocytes with Epstein-Barr-virus transformed autologous B cells as antigen-presenting cells. The two advantages of this method are that it drastically reduces the number of autologous peripheral blood mononuclear cells (less than 10(7) cells) needed to obtain and propagate these T-cell clones (TLC), and that it enables us to expand individual TLC to large numbers of cells (greater than 10(8)). Thus the major obstacles for the cloning of T lymphocytes--especially important with regard to patients--are bypassed. Thus far, TLC from three leprosy patients have been established. These TLC are HLA class II restricted in their M. leprae-directed response. A marked enhancement in antigen responsiveness was observed after further expansion of several TLC, some of which turned from nonresponder into responder TLC. Four tested TLC display strikingly different antigen recognition patterns when tested against a number of other mycobacterial antigens; one TLC so far recognizes only M. leprae antigens.