Short Communication : Simian T Cell Leukemia Virus Type I-Induced Malignant Adult T Cell Leukemia-Like Disease in a Naturally Infected African Green Monkey: Implication of CD8 + T Cell Leukemia

Spontaneous T cell leukemia was found in an African green monkey (Cercopithecus aethiops, AGM) naturally infected with simian T cell leukemia virus type I (STLV-I). The hematological features and the evidence for monoclonal integration of provirus DNA in the leukemic cells revealed that the leukemia was an ATL-like disease. The expression of surface markers on the leukemic cells indicated that they were defined as an activated CD8⁺ T cell subset. Together with the finding that seven in vitro spontaneously STLV-I-transformed cell lines were CD4⁻CD8⁺, it is likely that CD8⁺ T cells are transformed by STLV-I in AGMs, in contrast with human ATL. Finally, we assessed characteristics of the CD8 chains on these transformed cells. The result indicated that the leukemic cells expressed only the α chains but not the β chains. However, in the case of in vitro-transformed cell lines the expression pattern of the CD8 chains varied in individual monkeys. Thus, STLV-I may preferentially transform CD8⁺ (both αα⁺ and αβ⁺) T cells in AGMs.