Athymic nude CD4+8- T cells produce IL-2 but fail to proliferate in response to mitogenic stimuli.
A comparative study of immune functions of CD4+8- T cells isolated from normal and athymic nude mice by electronic cell sorting was performed. Athymic nude CD4+8- T cells expressed the TCR-associated CD3 molecule but the level of expression was significantly lower than that of normal CD4+8- T cells. Proliferative responses were studied upon stimulation by 1) the T cell mitogen Con A; 2) anti-CD3 mediated cross-linking of the CD3:TCR complex, and 3) the combined action of PMA + ionomycin. All three mitogenic stimuli caused readily detectable cell division in normal (euthymic) CD4+8- T cells. In marked contrast, none of the mitogenic stimuli induced significant proliferation in athymic nude CD4+8- T cells. The failure of athymic nude CD4+8- T cells to proliferate occurred over a wide range of mitogen concentrations and over a 4-day observation period. Neither exogenously supplied rIL-2 or mixed lymphocyte culture supernatant had any effect on the impaired proliferative response by athymic nude CD4+8- T cells. Although IL-2 was produced by athymic nude CD4+8- T cells at a reduced level when compared to normal CD4+8- T cells, it was nevertheless readily detected upon stimulation with either Con A or anti-CD3. Furthermore, stimulation of athymic nude CD4+8- T cells by anti-CD3 induced the expression of the p55 chain of IL-2R on the cell surface. Therefore, despite production of IL-2 and induced expression of IL-2R, athymic nude CD4+8- T cells failed to undergo cell division.
Kung
J T
JT
Department of Microbiology, University of Texas Health Science Center, San Antonio 78284.
Thomas
C A
CA
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D017252:CD3 Complex; D007376:Interleukin-2 / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008934:Mitogens; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000002:abnormalities / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D007376:Interleukin-2; D008934:Mitogens; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2