| Budget Amount *help |
¥9,900,000 (Direct Cost: ¥9,900,000)
Fiscal Year 1990: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1989: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1988: ¥4,900,000 (Direct Cost: ¥4,900,000)
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| Research Abstract |
In order to study the mechanisms in maturation of human T cells in thymus, a part of human thymus was obtained from patients with congenital heart diseases at their operation. Using bovine serum albumin discontinuous density gradient method, thymocytes were fractionated into 5 populations. Each fraction was studied for the expression of T cell antigens, CD1, 3, 4, 8, 25, 45, and WT31 by flow-cytometry analysis. They were also cultured in the presence or absence of IL-2 or IL-4. Finally, DNA extracted from each thymocyte population were analyzed for the rearrangement of T cell antigen receptor beta and gamma chain.
There were more CD3^<low+> or CD4^+CD8^+ double positive population in high density fraction than in lower density population. In contrast, there were less CD4^+CD8^- or CD4^-CD8^+ single positive population in high density fraction. In the analysis of surface T cell antigen receptor, the expressions of were in direct proportion to that of CD3 in all fractions. Although the pe
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ak of their distribution was observed at negative region in Fr. I, the peaks were obtained at both the same region and high intensity region in Fr. III. However, that in Fr. V was observed at low intensity positive region.
In the induction analysis of IL-2R, the addition of PMA induced surface IL-2R on the CD3^+ cells in all fractions, although the addition of PHA or Con A did not induce on CD3^+ cells in Fr. V. In the analysis of proliferative response to mitogens, the cells in Fr. I responded to the addition of PHA or Con A although those in Fr. III did not response even with rIL-2. The addition of PMA with rIL-2 induced the proliferative response in all fraction although that without rIL-2 did not induce in any fractions.
In the induction analysis of 2H4 antigen of thymocytes in Fr. III, the addition of rIL-4 alone induced 2H4 antigen only in CD3^+ population, although PMA alone did not induce in any population. Moreover, rIL-4 and PMA induced surface 2H4 antigen much intensively in CD3^+. In thymocytes in Fr. V, the additions of rIL-4 and PMA slightly induced 2H4 antigens in both of CD3^+ and CD3^- populations although rIL-4 alone did not induce anymore.
Finally, in the analyses of T cell antigen receptor beta chain rearrangement, polyclonal rearrangements were observed in all fractionated thymocyte populations, suggesting non-functional rearrangements occurred in high density population. Less
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