Functional significance of CD23- on CD23-transfected Th2 clone.
CD23, a low-affinity IgE Fc receptor, is not displayed on most resting T cells but its expression has been shown to be transiently induced in vivo and in vitro on some CD4+ T cells [1-4] and in vivo on CD8+ T cells by IgE-secreting hybridoma tumors [5]. To investigate the functional role of CD23 on T cells, we inserted a CD23 construct into an expression vector driven by a CD2 promoter and transfected it into a murine Th2 clone D10.G4.1 (D10). We stimulated the transfected D10 cells (D10.3M.24) with anti-TCR antibody in the presence or absence of IgE, and measured IL-4, IL-5 and IL-6 production in the culture supernatants. Activation of D10.3M.24 cells by anti-TCR antibody induced greater levels of IL-4, IL-5 and IL-6 production, when the TCR and CD23 were co-crosslinked by TNP anti-TCR and IgE anti-TNP antibodies. IgG anti-TNP antibody did not enhance lymphokine production by D10.3M.24 cells. The enhanced lymphokine production by IgE was blocked by monoclonal anti-CD23 antibody. IgE anti-TNP antibody did not enhance lymphokine production by the wild-type D10 cells induced by TNP anti-TCR antibody. These studies show that when co-crosslinked with the TCR, CD23 can modulate the lymphokine production in activated Th2 cells. Since CD23 binds to IgE and also binds to CD21 [6], a complement receptor commonly expressed on B cells, T-cell CD23 could play an immunoregulatory role during cognate T-B cell interaction and during IgE antibody responses.
Nambu
M
M
Department of Pathology, College of Medicine, University of Iowa, Iowa City 52242, USA.
Hagen
M
M
Sandor
M
M
Sacco
R E
RE
Kwack
K
K
Lynch
R G
RG
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000954:Antigens, Surface / Q000235:genetics / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology; D002999:Clone Cells; D007378:Interleukins / Q000096:biosynthesis*; D051379:Mice; D018448:Models, Immunological; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism*; D017455:Receptors, IgE / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology*; D014162:Transfection
D000906:Antibodies; D000954:Antigens, Surface; D007378:Interleukins; D011948:Receptors, Antigen, T-Cell; D017455:Receptors, IgE; D011993:Recombinant Fusion Proteins