Inhibition of Neisseria gonorrhoeae attachment to HeLa cells with monoclonal antibody directed against a protein II

This study showed that a protein II (PII) of Neisseria gonorrhoeae FA1090 appeared to act as a mediator of attachment to HeLa cells. Two colony variants of FA1090 were selected. Both gonococcal variants were nonpiliated, but one contained a PII and the other did not. A monoclonal antibody (1090-10.1), which was directed against the PII, inhibited the apparent PII-mediated attachment to HeLa cells. Antibodies produced from clone 1035-4, which had no PII specificity, did not inhibit the attachment and were used as controls. Inhibition of gonococcal attachment by the 1090-10.1 monoclonal antibodies was demonstrated by fluorescent microscopy analysis. Monoclonal antibody 1090-10.1 appeared to cause agglutination of the PII-containing organism. To block the clumping caused by the PII-specific monoclonal antibodies, Fab fragments of goat anti-mouse IgG were incubated with gonococci and the 1090-10.1 monoclonal antibodies. The results showed that the goat anti-mouse IgG Fab fragments partially blocked the agglutination caused by the PII-specific monoclonal antibody. The effect of the 1090-10.1 antibodies on attachment was also determined by monitoring the HeLa cells with attached iodinated gonococci. The monoclonal antibody appeared to inhibit the PII-mediated attachment.