The molecular
basis of adhesion of Trichomoniasis vaginalis has been investigated, and four
antigenic surface molecules have also been implicated in the
adhesion of Trichomoniasis vaginalis to vaginal epithelial cells; their expression is being upregulated during attachment to host cells.
Antibodies to these molecules protected target cells from parasite-mediated cytotoxicity, suggesting that antiadhesion
immune responses could be important in in vivo protection
against the pathogenic effects of Trichomoniasis vaginalis.
However, our current understanding of immunity to Trichomoniasis vaginalis remains unsatisfactory, and it is not clear whether acquired immune responses are required for protection and, if
so, what role is played by acquired immunity in containing or
eliminating infections.
Although there is some evidence that
protection may be achieved by immunization of laboratory
animals, strong protective immunity does not seem to follow natural infection in humans. A recent study of patients
infected with Trichomoniasis vaginalis and HIV indicated no evidence of
increased levels or longevity of parasite infection in these patients compared to those in patients infected with Trichomoniasis vaginalis
but not HIV.
These observations may indicate that innate
immunity involving chemotaxis and subsequent influx of neutrophils is much more important than acquired immunity in
controlling infections with Trichomoniasis vaginalis, since neutrophils are
often the most numerous leukocytes present in response to
infection .