Adjuvant modulation of T-cell reactivity to 30-kDa secretory protein of Mycobacterium tuberculosis H(37)Rv and its protective efficacy against experimental tuberculosis

The immunoprotective behaviour of the 30-kDa secretory glycoprotein of Myco bacterium tuberculosis H(37)Rv has been investigated in different adjuvant systems in two mouse strains, NMR1 and C57BL/6J. In comparison with Freund' s incomplete adjuvant (FIA) and dimethyldioctadecyl ammonium bromide (DDA), the 30-kDa glycoprotein complexed with polylactide-co-glycolide microparti cles (PLG-MPs) induced maximum immunoreactivity in the two mouse strains. A s compared,vith controls, immunisation with 30-kDa-PLG-MPs resulted in sign ificantly greater protection in animals challenged with 1 x LD50 of M, tube rculosis H37Rv On the basis of survival rates and number of cfu in the infe cted organs 30 days after challenge. The degree of protection provided by 3 0-kDa-PLG-MPs was similar to that obtained with 30-kDa-FIA and higher than BCG immunisation. These findings suggest that biodegradable PLG micropartic les can be used as an efficient carrier system for the key immunoprotective 30-kDa secretory protein antigen of M, tuberculosis H(37)Rv.