Expression of CD45 isoforms correlates with differential proliferative responses of peripheral CD4+ and CD8+ T cells.
CD4(+) T cells express IL-2 receptor complexes to the same level as CD8(+) T cells when the two T cell populations were stimulated simultaneously. However, the activation of downstream signaling molecules, such as Jaks, was increased in CD8(+) T cells. Although equivalent amounts of CD45, which acts as a Jak phosphatase, was expressed on the two T cell populations, those on the CD8(+) T cells have less protein tyrosine phosphatase activity than those on the CD4(+) T cells. Furthermore, we find that different CD45 isoforms dominate in the two populations; CD45RO on proliferating CD4(+) T cells and CD45RBC on proliferating CD8(+) T cells. In addition, NIH3T3 cells expressing the CD45RBC transgene had more phosphorylated Jak1 and grew faster than those with the CD45RO transgene. Thus, the expression of specific CD45 isoforms on T cells correlates with their proliferative response to IL-2, suggesting that controlling cells expressing specific CD45 isoforms could correct excessive or insufficient immune responses.
Seki
Iwao
I
Department of Medicine and Rheumatology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Suzuki
Mihoko
M
Miyasaka
Nobuyuki
N
Kohsaka
Hitoshi
H
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D002469:Cell Separation; D003001:Cloning, Molecular; D005434:Flow Cytometry; D007376:Interleukin-2 / Q000378:metabolism; D053613:Janus Kinase 1 / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection
D007376:Interleukin-2; D020033:Protein Isoforms; D053613:Janus Kinase 1; D017493:Leukocyte Common Antigens