MOLECULAR MIMICRY BY MYCOPLASMA-PNEUMONIAE TO EVADE THE INDUCTION OF ADHERENCE INHIBITING ANTIBODIES

Specific regions of adherence binding sites and epitopes of the P1 adh esin of Mycoplasma pneumoniae were synthesised as octapeptides and use d as targets in a modified enzyme-linked immunosorbent assay. Acute ph ase and convalescent sera from 10 patients with M. pneumoniae infectio n were tested for antibody reactivity to these octapeptides. In conval escent sera, antibody activities were directed against octapeptides of the epitope regions, whereas no antibody activity was found in acute or convalescent sera to octapeptides of adherence-mediating binding si tes. The non-responsiveness to adherence-mediating binding sites could be explained partially from the results of cross-reactivity experimen ts with adherence-inhibiting anti-Pi adhesin monoclonal antibodies (MA bs). Two of these MAbs showed cross-reactions with intracellular antig ens of eukaryotic cell lines in immunofluorescence microscopy experime nts. The cross-reacting antigens were isolated and characterised as gl yceraldehyde-3-phosphate dehydrogenase and 2-phospho-D-glycerate hydro lyase. Antigenic mimicry of eukaryotic structures by functional sites of the P1 adhesin of M. pneumoniae may influence the pathogenesis of M . pneumoniae infection.