Interleukin-2 (IL-2) receptor alpha, beta and gamma subunit expression as a function of B-cell lineage ontogeny: the use of IL-2-PE66(4Glu) to characterize internalization via IL-2 receptor subunits.
Interleukin-2 (IL-2) is a pluripotent cytokine which plays a crucial role in the immune system response. Although the IL-2/IL-2 receptor (IL-2R) system has been well characterized in cells of the T lineage it is less known in B lymphocytes. The authors therefore studied the expression of the IL-2R alpha, beta and gamma subunits in human B-cell lines at different stages of maturation, by the polymerase chain reaction technique. The authors found that the alpha and beta subunits are expressed in the final stages of B-cell lineage maturation, whereas the gamma subunit is constitutively expressed during B-lymphocyte differentiation. The results indicate that the IL-2/IL-2R system, most probably, does not have a role in the early stages of B-cell differentiation, but may be involved only in the final stages of B-cell lineage ontogeny. Moreover, the ability of the different forms of IL-2R to internalize the IL-2 ligand was investigated, using the chimeric protein IL-2-PE66(4Glu). Cell lines bearing the alphagamma, betagamma and alpha betagamma forms of IL-2R were inhibited by the chimeric protein, while those bearing the gamma subunit alone did not respond to the chimera. Thus, internalization of IL-2 is most likely mediated via the alphagamma form of the IL-2R, as shown here for the first time, as well as through the betagamma and alpha betagamma IL-2R forms. However, IL-2 cannot be internalized through the IL-2R gamma subunit alone.
Steinberger
I
I
Department of Cellular Biochemistry, Hebrew University-Hadassah, Medical School, Jerusalem, Israel.
Ben-Bassat
H
H
Hochberg
E
E
Lorberboum-Galski
H
H
D001402:B-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D019070:Cell Lineage / Q000502:physiology; D002478:Cells, Cultured; D017931:DNA Primers / Q000737:chemistry; D004705:Endocytosis / Q000502:physiology*; D005098:Exotoxins / Q000494:pharmacology*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology*; D008024:Ligands; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins / Q000494:pharmacology
D017931:DNA Primers; D005098:Exotoxins; D007376:Interleukin-2; D008024:Ligands; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C065698:interleukin 2-PE66(4Glu) protein, recombinant