Induction of Fc epsilon RII/CD23 on PHA-activated human peripheral blood T lymphocytes and association of fyn tyrosine kinase with Fc epsilon RII/CD23.
Despite the evidence for the expression of Fc epsilon RII/CD23, a glycoprotein that is a low-affinity Fc receptor for IgE, obtained on T cell lines and some pathological T cells, that of Fc epsilon RII/CD23 on normal human T cells is still unclear. We studied the emergence of T cells bearing Fc epsilon RII/CD23 in short-term culture of normal human peripheral blood mononuclear cells stimulated with 15 microliters/ml phytohemagglutinin (PHA). Using two-dimension flow cytometry, more than 10% of Fc epsilon RII/CD23(+) cells were shown to co-express CD3 antigen. Both CD4(+) and CD8(+) T cells expressed Fc epsilon RII/CD23. The expression of mRNA for Fc epsilon RII/CD23 on PHA and IL-4 stimulated PBMC was demonstrated by northern blotting and in-situ hybridization. The mechanism of signal transduction through Fc epsilon RII/CD23 was dissected by transfection of cDNA coding for Fc epsilon RII to the human natural killer-like cell line YT, activation of which was easily detected by the induction of interleukin-2 receptor/p55 (Tac). Cross-linking of Fc epsilon RII/CD23 with H107 anti-Fc epsilon RII monoclonal antibody enhanced IL-2R/p55 expression on YT cells transfected with Fc epsilon RII cDNA (YTSER). A possible involvement of protein-tyrosine kinase in the Fc epsilon RII-mediated signal transduction was studied using YTSER. Fc epsilon RII was physically associated with an src-family tyrosine kinase p59fyn and not with p56lck, which was also found in YT cells. Recently it was reported that p59fyn was associated with T-cell antigen receptor. Our results collectively suggest the multiple function of p59fyn which may be implicated in the Fc epsilon RII-mediated activation signal in YT cells.
Maekawa
N
N
Department of Biological Responses, Kyoto University Medical School, Japan.
Kawabe
T
T
Sugie
K
K
Kawakami
T
T
Maeda
Y
Y
Uchida
A
A
Yodoi
J
J
D015152:Blotting, Northern; D002461:Cell Line, Transformed; D006801:Humans; D015151:Immunoblotting; D017403:In Situ Hybridization; D008213:Lymphocyte Activation; D010449:Peptide Mapping; D010835:Phytohemagglutinins / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn; D017455:Receptors, IgE / Q000096:biosynthesis*; D013601:T-Lymphocytes / Q000187:drug effects*
D010835:Phytohemagglutinins; D011518:Proto-Oncogene Proteins; D017455:Receptors, IgE; D011505:Protein-Tyrosine Kinases; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn