AGGREGATION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 BY HUMAN SALIVARY SECRETIONS

Human immunodeficiency virus (HIV-1) is generally transmitted by paren teral contact with infected body secretions. Although extensive epidem iological data and familial studies have failed to provide any conclus ive data that saliva may act as a vehicle for transmission of AIDS, bo th professional and public anxieties remain. The present study, as wel l as others, suggests that salivary secretions may act as inhibitors o f HIV-1 replication in vitro. In our study, the inhibitory activity wa s determined to be associated mainly with secretions obtained from the human submandibular-sublingual glands. Human submandibular-sublingual (HSMSL) and parotid (HPS) salivas were collected and tested for their ability to modulate the replication of HIV-1, using a plaque assay on HeLa/CD4+ cell monolayers. Initial results examining freshly collecte d salivary samples from ten individuals confirmed the results previous ly obtained by Fox et al. (1988, 1989). An average plaque reduction of approximately 66% was obtained with HSMSL, in contrast to 34% reducti on obtained with HPS. Titration of the inhibitory activity in HSMSL sh owed detectable levels at a 1:500 dilution. Comparison of inhibitory a ctivity of dialyzed and lyophilized saliva to fresh saliva indicated l ittle difference between the two samples when filtration occurred afte r the addition of HIV-1. However, the effect of filtration was signifi cantly diminished in the lyophilized samples. Electron microscopic exa mination of the saliva-HIV incubates revealed the aggregation/entrapme nt of virus particles by salivary components. These results suggest th at human salivary secretions (with HSMSL > HPS) may have a role in mod ulating the infectivity of HIV-1.