FIBRONECTIN-BINDING ANTIGEN-85 AND THE 10-KILODALTON GROES-RELATED HEAT-SHOCK PROTEIN ARE THE PREDOMINANT TH-1 RESPONSE INDUCERS IN LEPROSYCONTACTS

Peripheral blood mononuclear cells from 27 healthy leprosy contacts we re analyzed for lymphoproliferation and TH-1 cytokine secretion (inter leukin-2 and gamma interferon) in response to heat shock proteins with molecular masses of 65, 18, and 10 kDa from Mycobacterium leprae and the 30-32-kDa antigen 85 (Ag 85) from Mycobacterium bovis BCG. Cells f rom 18 and 19 of 19 lepromin-positive contacts proliferated or produce d TH-1 cytokines in response to the M leprae 10-kDa protein and to Ag 85, respectively. Limiting-dilution analysis for two lepromin-positive contacts indicated that about one-third of M. leprae-reactive T cells displayed specificity to the M leprae 10-kDa protein and Ag 85. The M leprae 65- and 18-kDa proteins were less potent TH-1 response inducer s: gamma interferon and interleukin-2 could be measured in 14 and 9 of 19 lepromin-positive contacts, respectively. In contrast, very low or undetectable proliferative and cytokine responses were found for 8 le promin-negative contacts. Our data demonstrate that the fibronectin-bi nding Ag 85 and the 10-kDa GroES homolog are powerful mycobacterial TH -1 response inducers in the vast majority of lepromin-positive contact s and suggest that they might be valuable candidates for a future subu nit vaccine.