Continued antigen stimulation is not required during CD4(+) T cell clonal expansion.
Peptide Ag initiates CD4(+) T cell proliferation, but the subsequent effects of Ag on clonal expansion are not fully known. In this study, murine CD4(+) T cells were labeled with the fluorescent dye CFSE and were stimulated with specific peptide Ag. Activation occurred, as CFSE-associated fluorescence was reduced 2-fold with each cell division. Separation of proliferating cells based upon CFSE fluorescence intensity showed that daughter cells from each cell division proliferate even after removal of Ag. A limited exposure (2 h) to peptide programmed the cells to proliferate independently of Ag. Although not required for cell division, Ag increased the survival of proliferating cells and increased the total number of cell divisions in the expansion process. These results indicate that Ag exposure begins a program of cell division that does not require but is modified by further TCR stimulation.
Lee
William T
WT
Laboratory of Clinical and Experimental Immunology and Endocrinology, Wadsworth Center, Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY 12201, USA. William.Lee@wadsworth.org
Pasos
Gregory
G
Cecchini
Luiza
L
Mittler
James N
JN
D000818:Animals; D000941:Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002470:Cell Survival; D002478:Cells, Cultured; D005434:Flow Cytometry; D005452:Fluoresceins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D007376:Interleukin-2 / Q000096:biosynthesis; D007700:Kinetics; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D013388:Succinimides / Q000737:chemistry
C087165:5-(6)-carboxyfluorescein diacetate succinimidyl ester; D000941:Antigens; D005452:Fluoresceins; D005456:Fluorescent Dyes; D007376:Interleukin-2; C111390:OVA 323-339; D010446:Peptide Fragments; D013388:Succinimides; D010047:Ovalbumin