Mouse Anti-Chicken TCRab/Vb1-PE

The monoclonal antibody TCR-2 precipitates a CD3-associated heterodimer of Mr 90 kDa (two bands of Mr 50 kDa and 40 kDa upon reduction) on chicken peripheral blood T cells. Deglycosylation of the heterodimer yields two polypeptides of Mr 34 kDa and 29 kDa. In the chicken, two distinct subpopulations of ?? T cells appear in the thymus subsequent to the appearance of ?? T cells. These subpopulations, originally denoted as TCR2 and TCR3, arise sequentially in the thymus during ontogeny and are now known to represent two distinct V? families, V?1 and V?2, respectively. The TCR-2 monoclonal antibody reacts with approximately 40% of thymocytes, 40-50% of blood mononuclear cells, and 40% of splenocytes in the chicken. Two-color immunofluorescence has revealed that most of the TCR2+ thymocytes express both CD4 and CD8 antigens. The TCR2+ cells in blood were found to express either CD4 (74 ± 2%) or CD8 (26 ± 4%). TCR2+ cells in the spleen also express either CD4 (37 ± 1%) or CD8 (64 ± 4%). Surprisingly, a relatively large subpopulation of CD8+ cells in the spleen are negative for TCR2. This observation led to the demonstration that 71 ± 6% of the TCR??+ cells in the spleen express CD8.