This contract is for the production of monoclonal antibodies against epitopes of the D/DR region of the major histocompatibility complex using EBV transformed B cell lines. The antibodies produced by these B cell lines will be characterized for specificity by conventional microcytotoxicity and flow cytometry methodologies. The antibodies identified and acquired will facilitate immunogenetic research such as the relationship between disease susceptibility and the MHC and the improvement of matching for transplantation.