Efficacy of culture filtrate protein preparations from Indian isolates of M-tuberculosis to activate T cells derived from healthy donors

SETTING: While culture filtrate proteins (CFPs) of Mycobacterium tuberculos is appear to be good vaccine candidates for tuberculosis, only CFPs derived from certain popular laboratory strains of M. tuberculosis have been studi ed for this purpose. OBJECTIVE: To compare the relative efficacies of CFP preparations from two laboratory strains and four contemporary clinical isolates of M. tuberculos is to induce T-cell activation. DESIGN: CFPs were isolated From six strains of M. tuberculosis and were use d to induce 1) T-cell proliferation, 2) IFN-gamma secretion, and 3) IL-12 s ecretion from peripheral blood derived mononuclear cell (PBMC) preparations from 33 healthy donors. RESULTS: Significant amounts of IL-12 were spontaneously secreted by PBMC p reparations; CFP preparations from two clinical isolates (JNU-7 and JNU-51) significantly boosted this response. All six CFP preparations induced IFN- gamma secretion by PBMCs. but those from two contemporary strains of M. tub erculosis (JNU-7 and JNU-22) were most effective in this regard. The effect of CFPs from JNU-7 and JNU-22 was significantly better than those from the laboratory strains (H37Ra and Erdman). Similar results were obtained with the T-cell proliferation parameter. CONCLUSION: These results suggest that CFPs derived from selected clinical isolates of hi. tuberculosis may outperform those of standard laboratory st rains, and mal: therefore be a better source of potential candidates for a tuberculosis vaccine.