FRACTIONATION OF MYCOBACTERIAL INTEGRAL MEMBRANE-PROTEINS BY CONTINUOUS ELUTION SDS-PAGE REVEALS THE IMMUNODOMINANCE OF LOW-MOLECULAR-WEIGHT SUBUNITS FOR HUMAN T-CELLS

Integral membrane proteins (IMP) represent a serologically distinct cl ass of mycobacterial antigens which are potent stimulators of human T cells (Mehrotra et al., Clin Exp Immunol 1995; 102:626). The range of LMP from Mycobacterium fortuitum was resolved by continuous elution SD S-PAGE to recover 31 discrete fractions covering bands up to approxima te to 58 kD. The fractions, after removal of SDS, were subjected to hu man T cell proliferation assays for the identification of immunodomina nt molecule(s). A low molecular weight (<20 kD) fraction was able to s timulate T cells from 11 out of 12 donors comprising mainly tuberculoi d leprosy patients. The described protocol is well suited to situation s where large quantities of antigenic protein mixtures must be process ed in order to get the purified molecules/fractions in amounts require d for immunoepidemiological studies.