IDENTIFICATION OF THE EPITOPE RECOGNIZED BY THE HUMAN V-BETA-5-SPECIFIC MONOCLONAL-ANTIBODY 42 1C1 - POTENTIAL IMPLICATIONS FOR DISEASE THERAPY/

A panel of T-cell clones was generated that was specific for amino aci d residues 4-13 of the mycobacterial 65-kd stress protein. All the clo nes were found to express a member of the V beta 5 family, as defined by PCR. However, the clones could be differentiated on the basis of di fferent staining characteristics with the mAb 42/1C1. This antibody is known to recognize both V beta 5.2 and V beta 5.3, as was the PCR pri mer pair used in the analysis. Sequencing of the TCRs revealed that th ose crones which were not stained by 42/1C1 expressed a previously uni dentified member of the V beta 5 family. By comparing the sequences of the V beta 5 family members chat are recognized by 42/1C1 with those that are not, we were able to identify a probable epitope for the anti body. It is also clear from our data that the TCRs of T cells recogniz ing identical MHC-peptide combinations, although very similar, may be differentiated by mAbs, thereby posing potential problems in any propo sed disease therapy involving treatment with monoclonals.