Cervical secretory immunoglobulin A to human papillomavirus type 16 (HPV16) from HPV16-infected women inhibit HPV16 virus-like particles-induced hemagglutination of mouse red blood cells.

Secretory immunoglobulin A (sIgA) antibodies are the first line of defence at the genital mucosa, and are thought to hinder viral infections by binding to conformational epitopes on the viral capsid. To investigate if cervical sIgA binds to conformational epitopes of the Human papillomavirus type 16 (HPV16), cervical mucus samples from 109 HPV16-infected patients were examined in a HPV16 virus-like particles-induced hemagglutination inhibition assay. 48 (44.1%) patients were able to inhibit hemagglutination. Inhibition of hemagglutination was associated with the presence of sIgA (P=0.001). In conclusion, naturally occurring cervical anti-HPV16 sIgA binds to and hinders conformational epitopes on the viral capsid, suggesting that these antibodies might have a neutralizing capacity.