Klebsiella 'modifying factor': binding studies with HLA-B27+ and B27- lymphocytes

On the basis that extracts of some klebsiella organisms bind selectively to the lymphocytes of HLA-B27+ individuals and induce the appearance of new antigens, attempts were made to detect the binding of klebsiella products to HLA-B27+ and B27- lymphocytes by a number of different techniques. Firstly, blocking of the binding of two different HLA-B27 specific monoclonal antibodies to HLA-B27+ lymphocytes has been examined following exposure of the lymphocytes to a cell-free culture filtrate from K. pneumoniae K21 and K43. There was no reduction in the cytotoxicity of either antibody, suggesting that neither of the epitopes detected by the anti-HLA-B27 monoclonal antibodies is a binding site for klebsiella products. Secondly, we have studied the binding of partially purified, radiolabelled klebsiella products to healthy HLA-B27+ and B27- lymphocytes. There was no significant difference either in terms of numerical counts bound or by comparing, by SDS-PAGE analysis, the molecules bound to each cell type. At the level of sensitivities of these techniques we can detect no difference in binding of klebsiella products to the lymphocytes of healthy HLA-B27+ and B27- individuals.