characteristic features in common with the genome of other retroviruses: long terminal repeats (L TR), and coding regions for internal proteins (gag), for re verse transcriptase (pol), and for glycosylated virion surface proteins (env) , ar ranged in the sequence gag, pol, env from the 5' to the 3' end of the genome. However, the HTL V genome also contains some specific features not shared with all other retroviruses: the LTR regions are unusually long (745 base pairs, with 298 base pairs constituting the R region), but unlike the long L TRs of mouse mammary tumor viruses, they do not contain open reading frames. A stretch of noncoding sequences separates the gag and the pol genes. Most interestingly, the HTLV genome contains a region between the 3' end of the env gene and the L TR, called the pX region, that encompasses four open reading frames. Leukemic T cells freshly obtained from patients contain the HTL V provirus but usually do not express it. However, once established in culture, these cells produce viral proteins and release type C particles. Likewise, T cells infected and transformed by HTL V in vitro synthesize virus. Such producing cell lines have been widely used in seroepidemiological surveys and continue to be of importance for detailed studies of viral proteins and nucleic acids.

Inhalt
Human T-Cell Leukemia/Lymphoma Viruses An Introduction.- Isolation, Characterization, and Biological Effects of the First Human Retroviruses: The Human T-Lymphotropic Retrovirus Family. With 1 Figure.- Human T-Cell Leukemia/Lymphoma Viruses (HTLV): A Unique Family of Pathogenic Retroviruses. With 2 Figures.- Epidemiology of Adult T-Cell Leukemia/Lymphoma in Japan. With 9 Figures.- Human T-Cell Leukemia/Lymphoma Viruses: Clinical and Epidemiologic Features.- Clinical Aspects of Adult T-Cell Leukemia/Lymphoma.- The Epidemiology of Human T-Cell Leukemia/Lymphoma Virus. With 5 Figures.- Adult T-Cell Leukemia/Lymphoma and Its Clinical Subtypes from the Viewpoints of Viral Etiology.- A Retrovirus Associated with a Human Leukemia, Adult T-Cell Leukemia.- Biology of Human T-Cell Leukemia Virus: Search for an Animal System. With 7 Figures.- Molecular Biology of Human T-Cell Leukemia Virus Associated with Adult T-Cell Leukemia. With 9 Figures.- Structure and Function of the Genome of HTLV. With 7 Figures.- Some Perspectives on the Molecular Mechanism of in Vitro Transformation and in Vivo Leukemogenesis by HTLV. With 3 Figures.- Primary Structure and Processing of gag and env Gene Products of Human T-Cell Leukemia Viruses HTLV-ICR and HTLV-IATK. With 9 Figures.- Envelope Properties of Human T-Cell Leukemia Viruses. With 3 Figures.- Human T-Cell Leukemia/Lymphoma Virus: Studies of Host-Virus Interaction. With 9 Figures.