Juxtacrine function of interleukin-15/interleukin-15 receptor system in tumour derived human B-cell lines.
Interleukin-15 (IL-15) is a cytokine that induces proliferation and promotes cell survival of human T, B and NK cells. IL-15 and interleukin-2 (IL-2) exhibit a similar spectrum of immune effects and share the IL-2 receptor (IL-2R) subunits IL-2Rbeta and IL-2Rgamma(c) for signalling in haematopoietic cells. Furthermore, each cytokine has a private alpha receptor, namely IL-2Ralpha for IL-2 and IL-15Ralpha for IL-15, that functions in ligand binding. Using reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) methods, the expression and secretion of IL-15 and IL-15Ralpha in tumour-derived B-cell lines were studied. The results as presented in this study identify that IL-15 mRNA is predominantly expressed in EBV positive (EBV(+)) B-cell lines, although IL-15Ralpha is ubiquitously and constitutively expressed in all these B-cell lines. Although no detectable levels of IL-15 protein secretion were observed in any of these cell lines, we were able to detect membrane-bound expression of IL-15 protein by FACS analysis in some cell lines. These data imply that the IL-15/IL-15R system requires complex regulatory mechanisms for protein secretion. Taken together, we speculate that these results suggest a juxtacrine, intracrine function for IL-15/IL-15R.
Tsukamoto
K
K
Laboratory of Cytokine Research, Department of Biology, University of West Florida, Pensacola, Florida 10032, USA.
Huang
Y C
YC
Dorsey
W C
WC
Carns
B
B
Sharma
V
V
D001402:B-Lymphocytes / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D019409:Interleukin-15 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016393:Lymphoma, B-Cell / Q000276:immunology*; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm; D053647:Receptors, Interleukin-15 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D019409:Interleukin-15; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D053647:Receptors, Interleukin-15