|Budget Amount *help
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1994 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1993 : ¥1,200,000 (Direct Cost : ¥1,200,000)
In many functions of thymic stroma cells, roles on migration of prothymocytes into the thymus is not well understood. It is considered that thymic stromal cells secret chemotactic factors to immigrate bone marrow cells into the thymus. Chemotactic activity was recovered in supernatant fluid of short term cultured rat thymus but not in that of the kidney and liver. This activity was detected in the thymus of young rats of many strains and old BUF rats. Reacting bone marrow cells present in 1.077 density fraction when separated with ficol-paque. Reactivity of bone marrow cells was different among rat strains and most reactive strain was BUF.Chemotactic factor was thought to have some roles on induction and pathological state of thymic tumors, thymic lymphoma and thymoma. Rat thymic lymphoma cells of primary tumor and established cell lines all reacted to this factor. Tumor cells that metastasized to the thymus is more reactive than that grew at primarily transplanted site, meaning that this factor also influence on metastasis process of lymphoma cells. For the purification of this factor, various medias for chromatography were tested ; effective for gel filtration, DEAE sepharose, and hydrophobic butyl-sepharose, but ineffective for columns of 4 rectins, heparin, hydroxyapatite, 5 dyes, and hydrophobic ether-sepharose. On the other hand, the gene coding this factor is thought to be one of genes determining sensitivity of thymic lymphomagenesis. Genetic analysis in N-nitrosourea-thymic lymphomagenesis was carried out with BUF,WKY,and their cross offspring. As a result, one gene determining latent period (temporarily TIs-3), whcih links to the Gc gene (coding vitamin D binding protein), was identified. However, linkage between chemotactic factor is still obscure. Relationship between susceptibility for thymic lymphomagenesis and chemotactic factor should be investigated further.