|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1999 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1998 : ¥2,000,000 (Direct Cost : ¥2,000,000)
Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. However, the fact that only a few carriers develop to the above diseases after a long latency makes it difficult to study their pathogenesis with human material. It would be helpful to establish a mouse model of HTLV-1-associated diseases to understand their pathogenesis. Recently we could infect newborn mice by inoculating HTLV-1-producing human cells. We found that T-cells, B-cells and granulocytes were infected in vivo. But it has been previously reported that cell-free HTLV-1 could not infect mouse fibroblast cells efficiently. To understand the mechanism of HTLV-1 transmission to mouse cells, we employed a highly transmissible cell-free HTLV-1 produced by a feline kidney cell line, c77 and studied the susceptibility of various kinds of mouse cells. Nine kinds of mouse cell lines, EL4, RLm1, CTLL-2, J774.1, DA-1, Ba/F3, WEHI-3, NIH3T3 and B1, and two kinds of human cell lines, Molt-4 and Hut78, were infected and the HTLV-1 provirus sequence was monitored by PCR. HTLV-1 proviral sequence was found in all 9 mouse cell lines as well as in 2 human cell lines and infection was blocked with serum from an ATL patient. Moreover mouse cell lines, EL4 and RLm1, and human cell lines, Molt-4 and Hut78, were infected by cell-free HTLV-1 with similar efficiency. These results indicate efficient cell-free HTLV-1 transmission to various mouse cell lines and suggest a wide distribution of HTLV-1 receptor in mouse cells.