Variability of CD3 membrane expression and T cell activation capacity

Background: αβT cells have a wide distribution of CD3 membrane density. The aim of this article was to evaluate the significance of the CD3 differential expression on T cell subsets. Analysis was performed on healthy donors and renal transplant patients by flow cytometry. The results obtained are: (1) CD3 expression was widely distributed (CV = 38.3 ± 3.1 to 43 ± 2.3%). (2) The CD4, CD8, CD45 and forward scatter were similarly distributed. (3) The diversity of CD3 expression was directly related to the clonotypes: γ9, non γ9 from γδT cells and Vβ clonotype from αβT cells (e.g., Vβ3FITC 7,980 ± 1,628 Vβ8PE: Vβ20‐FITC 11,768 ± 1,510). (4) Using a computer simulation, we could confirm differential kinetics of T cell activation according to the initial parameters. Finally, in vitro activation was significantly higher on Vβ8 and Vβ9 (high CD3) compared with Vβ2 and Vβ3 (low CD3, P = 0.040–0.0003). In conclusion, T cells have highly heterogeneous CD3 expression, possibly predetermined and with clear functional significance. © 2009 Clinical Cytometry Society