Figure 2

Binding of HIV-1 IIIB and BaL, respectively, to Aquateric in the presence of human seminal fluid. Five hundred μl aliquots of a formulation containing Aquateric (18% Aquateric, 6% hydroxypropyl methylcellulose, 76% glycerol) were mixed with graded volumes of seminal fluid (range: 100 μl – 1,000 μl) each containing equal amounts of purified HIV-1 IIIB (6.8 × 10⁹ particles) and BaL (2.5 × 10⁹ particles), respectively. After incubation for 5 min at 37°C the mixtures were cooled in ice, centrifuged at 10,000 rpm for 10 min in order to pellet Aquateric. The supernatant fluids were all adjusted to identical volumes (1.5 ml) and NP40 was added to a final concentration of 1%. After incubation for 30 min at 37°C, serial 5-fold dilutions (1/1,000 to 1/3.9 × 10⁸) were prepared and p24 antigen in each dilution was measured by ELISA. The percentage of p24 antigen (representing a relative measure of the number of HIV-1 virus particles) was determined from calibration curves relating absorbance readings to the concentration of p24 antigen.