Effect of interleukin-7 and -15 on activation of purified umbilical cord blood and adult peripheral blood CD4+ T cells.
We investigated the effect of two IL-2 receptor gamma chain (IL-2R-gammac)-signaling cytokines, IL-7 and IL-15, on the activation of purified CD4+ lymphocytes from umbilical cord blood (CB) and adult peripheral blood (APB) by assessing the expression of the IL-2 receptor-alpha (CD25) and Fas (CD95) on CD45RA+ (naïve) and CD45RO+ (memory) CD4+ subsets. Induced CD40L (CD154) expression following phorbol 12-myristate 13-acetate and ionomycin (P+I) stimulation was also examined on cultured CB CD4+ cells. Incubation with IL-15 at 10 ng/ml resulted in a significant increase in the mean fluorescence intensity (MFI) of CD25 on CB CD4+/CD45RA+ cells (exceeding those of APB) without affecting the percentage of CD25-expressing CD45RA+ cells (%CD25/CD45RA). In contrast, both CD25 MFI and %CD25/CD45RA were enhanced on IL-15-treated APB CD4+ cells. CD95 expression (both percent expression and MFI) on CB CD4+/CD45RA+ cells were also enhanced by IL-15, but to a lesser extent compared to the response of ABP. IL-7, used at a concentration equivalent to IL-15, had little effect on APB CD25/CD95 and CB CD25 expression, but did enhance %CD95 expression on CB CD4+/CD45RA+ cells. Both IL-7 and IL-15 could augment the P+I-induced CD40L expression on CB CD4+/CD45RA+ T cells. However, the enhancing effect of IL-15 on CB CD40L/CD45RA expression was more sustained than that of IL-7. Thus, our study demonstrated differential activation of CB CD4+/CD45RA+ cells in response to IL-7 and IL-15 compared to adult counterparts, and the different T-enhancing function between IL-15 and IL-7.
Lin
Syh-Jae
SJ
Division of Asthma, Allergy, and Rheumatology, Department of Pediatrics, Chang Gung Children's Hospital, Taoyuan, Taiwan. alicehsu@adm.cgmh.com.tw
Cheng
Po-Jen
PJ
D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002470:Cell Survival; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007231:Infant, Newborn; D019409:Interleukin-15 / Q000494:pharmacology*; D015851:Interleukin-7 / Q000494:pharmacology*; D015759:Ionomycin / Q000494:pharmacology; D017493:Leukocyte Common Antigens / Q000032:analysis; D008213:Lymphocyte Activation / Q000187:drug effects*; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019014:fas Receptor / Q000032:analysis
D019409:Interleukin-15; D015851:Interleukin-7; D015375:Receptors, Interleukin-2; D019014:fas Receptor; D015759:Ionomycin; D017493:Leukocyte Common Antigens; D013755:Tetradecanoylphorbol Acetate