The virus, a member of the herpes family, 'locks' on to the same entry point of the blood cell - which is an important component of the immune system - as HIV. Lab tests show Human Herpes Virus-7 (HHV7) can prevent HIV infection in cell cultures.
Dr Robert Gallo, of the National Cancer Institute in Bethesda, Maryland, described the 'accidental observation', which has opened up a new attack against HIV, to the International Aids Conference in Berlin.
Dr Gallo, who summarised the work of several laboratories in the United States, said administering HHV7 as a whole virus was not likely. The protein surrounding the virus, which was responsible for it binding to the entry site, had to be identified and isolated. It may be possible to deliver this protein to patients to block the entry site on the white blood cell. He said his laboratory was 'actively pursuing' this new therapy.