THE ANTI-HIV-1 ACTIVITY ASSOCIATED WITH SALIVA

This review summarizes the data on the anti-human immunodeficiency vir us (HIV) activity associated with saliva and the possible routes of or al transmission of HIV. Saliva can be passed from an HIV-infected indi vidual to an uninfected person via sexual or non-sexual activities. Th e relative risk of HIV transmission through saliva is a subject of con tinuing concern for dental practitioners. HIV-infected individuals fre quently have oral lesions that can cause bleeding and release of the v irus into the oral cavity. In addition, viral p24 and HIV-1 RNA were d etected in tonsils and adenoids even in asymptomatic seropositive indi viduals. Nevertheless, the potential HIV-infectivity of saliva is low, although both infectious HIV-1 and HIV DNA have been detected in sali va. This observation has led to the suggestion that saliva may contain factors that inhibit HIV-1 infectivity. At least two anti-HIV activit ies have been partially characterized: (i) physical entrapment of HIV by high-molecular-weight molecules (eg. mucins), and (ii) inhibition o f viral infection by soluble proteins. Several studies have indicated that, of the salivary proteins evaluated, recombinant secretory leukoc yte protease inhibitor (rSLPI) could inhibit HIV-1 infection in macrop hages at physiological concentrations. The anti-HIV activity of the se rine protease inhibitor rSLPI is most likely due to its interaction wi th a cell-surface molecule(s) other than the primary HIV-1 receptor, C D4, and may involve (i) inhibition of cell-surface serine protease(s), and/or (ii) interaction with other human-specific co-factors essentia l for viral entry.