Micro-carrier-test: evaluating disinfectants for HIV.

Abstract

To determine the effect of disinfectants against viruses in vitro, I devised the Micro-Carrier-Test of dry-fixed virus-infected cells. Human immunodeficiency virus type 1-infected Molt-4 cells (1 x 10(5) cells in 5 microliters of 10% fetal bovine serum) were dry-fixed at the bottom of each well of a 96-well flat-bottomed microtiter plate for 120 minutes at room temperature. Disinfectants were added and allowed to remain for designated times and the wells were washed three times with PBS. Uninfected Molt-4 cells (1 x 10(4) cells/well) were inoculated and cultured for 4 weeks. The culture supernatant was harvested to measure reverse transcriptase activity by non-radioisotopic reverse transcriptase assay every week. Residual cytotoxicity of the disinfectant was determined by cytotoxicity assay. To evaluate the new method, the virucidal efficacy of several well-known disinfectants was reevaluated. Dose- and time-dependent effects of the disinfectants were determined. The minimal effective concentrations after 5 minutes of contact were 20% ethanol, 0.01% glutaraldehyde and 0.1% sodium hypochlorite. These results are almost the same as those reported previously, but there are some discrepancies. The differences between the present and previous protocols are discussed. This Micro-Carrier-Test promises to be useful in the screening of disinfectants.