ANTI-INFECTIVITY ACTIVITY OF HUMAN SALIVARY SECRETIONS TOWARD HUMAN-IMMUNODEFICIENCY-VIRUS

The purpose of this investigation was to adapt an MT-2 cell syncytium- forming assay for measuring anti-infectivity activity of salivary secr etions toward HIV and to determine the distribution of this activity i n a population of healthy adult subjects. Whole saliva samples were co llected from 27 volunteers, who reported that they did not belong to a ny group at high risk for HIV infection, and tested for anti-infectivi ty activity using the syncytium-forming assay. Nine of these subjects were subsequently retested on one or more occasions to assess the vari ability in appearance of this activity. Parotid and extraparotid saliv as of six subjects were also tested. Samples were frozen immediately a fter collection and submitted in blinded fashion for quantitation of t heir anti-HIV activity using a syncytia-forming MT-2 cell assay or the p24 antigen ELISA. Nine out of the 27 subjects showed detectable anti -HIV infectivity activity. One parotid sample and one extraparotid sam ple out of four from subjects with positive whole salivas were positiv e and none of the parotid or extraparotid samples from two subjects wi th negative whole salivas were positive. The inhibitory activity range d from 0.5 to 1 log 10 TCID50/ml and could not be correlated with tota l protein content in saliva or any specific electrophoretic component. Filtration of the saliva through an Amicon 10 filter before incubatio n with the virus abolished the activity. Similar studies using two oth er biological fluids, urine and cerebrospinal fluid, revealed no anti- HIV infectivity activity. These findings confirm the presence in saliv a of inhibitory activity directed toward HIV.