Diversity of immunobiological functions of T-cell lines established from patients with adult T-cell leukaemia

Abstract

In order to understand the variety of HTLV‐1‐associated cutaneous diseases, we studied the cytological profile of HTLV‐1‐infected T‐cell lines established from patients with adult T‐cell leukaemia (ATL). Among four CD4⁺ cell lines, termed 16T(−), 35T(−), MH‐1, and KS‐2, the 16T(−) cells secreted elevated quantities of IL‐4, IL‐b and IFN‐7, and expressed mRNA for each cytokine in the absence of exogenous stimulation. The 3ST(−) cells secreted IL‐6 and a small amount of IFN‐7, but not IL‐4. The MH‐1 and KS‐2 cells secreted only 1L‐6 in the absence of stimulation, hi response to stimulation with phorbol‐12‐myristate‐13 acetate (PMA), the 16T(−) cells produced more IL‐4 and IFN‐γ, whereas the 35T(−) and MH‐1 cells exhibited increased secretion of IFN‐γ, but still no IL‐4 or IL‐4 mRNA production. Although neither IL‐4 nor IFN‐γ were found in the culture supernatant of KS‐2 cells, the production of IL‐4 mRNA was detected by RT PCR. Culture supernatants from the 16T(−) and 35T(−) cells induced the expression of intercellular adhesion molecule‐1 (ICAM‐1) and HLA‐UR by cultured keratinocytes. This response was inhibited by pretreatment of the supernatant with anti‐IFN‐γ antibodies. These results indicate that some HTLV‐1‐infected T‐cell lines constitutively secrete various cytokines, including biologically active IFN‐γ. The diversity of immunobiological functions of the T‐cell lines may be related to the variety of clinical features present in ATL patients.