Human T-Cell Lymphotropic Retroviruses (HTLV) Associated with T-Cell Malignancy and Immunodeficiency: In Vitro Studies

Abstract

The first human retrovirus, human T-cell leukemia/lymphoma virus type I (HTLV-I) was discovered in the cultured leukemic cells of a patient with mature T-cell malignancy1,2. Using the new methodology for culturing of mature T-cells3 and the experience with the first HTLV isolates, hundreds of HTLV isolates were obtained in our and other laboratories within a relatively short period of time4,5. Propagation of these isolates in the appropriate host cell type provided a system for large scale production and, thus, enabled their extensive characterization1,4,6. Based on specific features, at present time, this rapidly expanding family of human retroviruses can be subdivided into three subgroups called HTLV-I, HTLV-II and HTLV-III7. This family of HTLV is naturally occuring retroviruses. In the past, this group of relatively commonly occuring retroviruses in nature were extensively studied in animals and they are called chronic leukemia viruses5,7. They are replicative competent and the cause of naturally occuring leukemia in chickens, mice, cats, cows, and gibbon apes.