Induction of CD69 antigen on normal CD4+ and CD8+ lymphocyte subsets and its relationship with the phenotype of responding T-cells

✍ Scribed by S. Rutella; C. Rumi; M.B. Lucia; T. Barberi; P.L. Puggioni; M. Lai; A. Romano; R. Cauda; G. Leone

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 176 KB
• Volume: 38
• Category: Article
• ISSN: 0196-4763
• DOI: 10.1002/(sici)1097-0320(19990615)38:3<95::aid-cyto1>3.0.co;2-l

✦ Synopsis

We evaluated phenotype and apoptotic status of normal CD4 ؉ CD69 ؉ and CD8 ؉ CD69 ؉ peripheral blood T-lymphocytes after short-term challenge with escalating concentrations of phytohemagglutinin (PHA). The frequency of CD69-coexpressing CD4 ؉ and CD8 ؉ T-cells and CD69 staining intensity increased following T-cell mitogenic stimulation; these changes were proportional to PHA concentration in culture medium. A considerable fraction of lymphocytes underwent blast transformation, displaying increased forward and side scatter signals. Interestingly enough, PHA-responsive T-cells exhibited a predominantly CD25 neg CD38 neg TCR␣␤ pos phenotype; APO-1/Fas antigen (CD95) could be detected on a minority of activated CD69 ؉ T-cells. A considerable proportion of CD69 ؉ lymphocytes expressed intracellular perforin; in addition, an average 16 ؎ 6% CD69 ؉ T-lymphocytes were apoptotic after 4 h of stimulation, as evaluated by 7-amino-actinomycin-D staining and by annexin-V binding. CD69 ؉ activated lymphocytes comprise phenotypically heterogeneous cell subpopulations potentially devoted to diverse immunological functions, i.e., proliferation, apoptosis, or cell cytotoxicity; moreover, our findings indicate that CD69 expression is proportional to the intensity of the activating stimulus and that the capacity to upregulate CD69 antigen following short-term mitogenic challenge may be restricted to unactivated CD38 neg CD25 neg TCR␣␤ pos T-lymphocytes. Cytometry (Comm. Clin.