This MAb reacts with cells bearing HLA-A25 or HLA-Aw32 antigens. In addition, a reaction was observed with a cell of phenotype A2, Aw31; B17, Bw49. HLA-A, with HLA-B and HLA-C, belongs to major histocompatibility complex (MHC) class I antigens and expresses constitutively on all nucleated cells. HLA system comprises closely linked genes controlling highly polymorphic proteins involved in the presentation of peptides to the T-cell receptor, inhibition of NK cell cytotoxicity, and rejection of tissue allotransplantation. Specific alleles at HLA loci are associated with diseases. This MAb is specifically applicable for typing peripheral T cells for the antigens HLA-A25 and HLA-Aw32.