DETERMINANT CAPTURE BY MHC CLASS-II DR3 DURING PROCESSING OF MYCOBACTERIA-LEPRAE 65KD HEAT-SHOCK-PROTEIN BY HUMAN B-CELLS

Using T cell immunoblotting we ha ie characterised the immunogenic fra gments derived from the Mycobacteria Leprae 65kD heat shock protein th at become associated with MHC class II DR3 during processing by a huma n B cell line. After 5 h incubation with antigen, a peptide of approxi mately 12kD (similar to 110 amino acids) was the only major fragment f ound associated with the class II MHC. The association of this oligope ptide was abolished if an excess of a synthetic peptide representing t he minimal epitope was included in the culture or when cells were incu bated at 4 degrees C. This suggests that the gen generation of this mo iety is dependent on cell metabolism and that its binding to MHC is sp ecific. This large fragment may represent an intermediate in the proce ssing pathway, directly demonstrating the role of MHC in determinant c apture during antigen degradation. (C) American Society for Histocompa tibility and Immunogenetics, 1998. Published by Elsevier Science Inc.