Isolation of AIDS virus from cell-free breast milk of three healthy virus carriers.

(=2x 105 ID/ml). Any treatment of AHF which is aimed at reducing the risk of transmitting LAV/HTLV-111 should therefore be capable of inactivating 2 x105 ID/ml of the virus. All of the above assumptions used to calculate the amount of LAV/HTLV-III that might be present in AHF were chosen to generate a worst-case situation, and a titre of 2 x 105 ID/ml therefore probably represents an overestimate since at this concentration and greater, one should easily be able to isolate the LAV/HTLV-111 virus using current cell culture techniques. To date no one has reported success in isolating LAV/HTLV-III virus from commercial AHF. Inactivation procedures which can be shown to reduce LAV/HTLV-III infectivity by 5 logs should therefore provide assurance that the preparation is no longer infectious. Heat inactivation kinetics data show that when LAV/HTLV-III is added