Antiviral effect of zidovudine in the experimental model of adult T cell leukemia in rabbits.

The antiviral effect of zidovudine was examined in an experimental model of adult T cell leukemia in rabbits. AZT retarded the growth of HTLV-I-transformed rabbit cell line (F647a) and inhibited the transformation of normal peripheral blood lymphocytes in co-culture with the cell line. Inhibition of the transformation was achieved at a much lower concentration of AZT than the suppression of cell growth. Seven newborn F1 hybrids were inoculated intraperitoneally with 1 x 10(7) F647a cells and then were given AZT intraperitoneally, either at a high dose (300 mg/kg/day) or a low dose (30 mg/kg/day) for three weeks. Four newborn animals similarly given F647a cells were left untreated as a control. Examinations carried out three weeks after cell inoculation revealed the following: the HTLV-I provirus was not or hardly detected by the polymerase chain reaction in the peripheral blood lymphocytes of animals given a high dose of AZT, whereas the provirus was detected in all untreated control animals as well as in two animals given a low dose of AZT. In addition, lymphocytic infiltration was not observed in the major organs of the former animals, but was observed in those of the latter animals. These indicate the effectiveness of AZT administration for the prevention of HTLV-I infection and ATL-like disease in rabbits.