特異性：Chicken TCR V alpha beta (V beta 2) MAb TCR3 precipitates a CD3-associated heterodimer of Mr 88-kDa (two bands of Mr 48-kDa and 40- kDa upon reduction) on chicken peripheral blood T cells.1,2 Deglycosylation of the heterodimer yields two polypeptides of Mr 34-kDa and 31-kDa from TCR3 precipitates. In the chicken, two distinct subpopulations of alpha beta T cells appear in the thymus subsequent to the appearance of gamma delta T cells. These subpopulations, originally denoted as TCR2 and TCR3,1,2 arise sequentially in the thymus during ontogeny and are now known to represent two distinct V beta families, V beta 1 and V beta 2, respectively.3 The TCR3 MAb reacts with approximately 9% of thymocytes, 15-25% of blood mononuclear cells and 13% of splenocytes young adult chickens. Two-color immunofluorescence has revealed that the TCR3+ thymocytes include CD4+CD8-, CD4-CD8+, CD4+CD8+ and CD4-CD8- subpopulations. The TCR3+ thymocytes can be separated into two subsets. One subset is characterized by relatively low levels of expression of the TCR3/CD3 complex and most of the cells in this subset are CD4+CD8+. Cells in the other subset express TCR3/CD3 in higher density and are either CD4+CD8- or CD4-CD8+, corresponding to the more mature medullary subset of thymocytes. The TCR3+ cells in the blood and spleen express relatively high levels of the TCR3/CD3 receptor complex and are "single positive, with CD4+CD8- cells being four times more frequent that the CD4-CD8+ cells (ca. 80% CD4+ vs ca. 20% CD8+).1,2
