Relationship between the cell expression property and immuno-regulating function was studied using peripheral ATL cells and cultured ATL cells collected from 2 patients with ATL. The result revealed that ATL cells do not only turn positive with OKT3+4+, but also turns positive with OKT17+ inhibiting the Ig production function of B cells of Ig producing system of the healthy subjects. The inhibitory effect does not need the presence of OKT4+ cells and OKT8+ cells, and is sensitive to irradiation, and also related to expression of ATL cells by OKT17+. Consequently, it was clarified that the ATL cells, although bearing OKT4+, have no helper function, but have the suppressor function with OKT17+. This is of interest in contemplating immunological abnormalities of this disease.
