Induction of apoptosis and tyrosine phosphorylation of cellular proteins in T cells and non-T cells by stimulation with concanavalin A.
A high concentration (30 microg/ml or more) of Con A caused the death of not only thymocytes but also splenic cells of BALB/c mice, whereas a moderate concentration (3 microg/ml) of Con A induced proliferation of these cells. A high concentration of Con A also induced the death of splenic cells of athymic BALB/c-nu/nu mice and the bone marrow cells of BALB/c mice which mainly consist of non-T cells. However, any concentration (1-30 microg/ml) of Con A failed to induce the proliferation of these cells. Specific binding of tetrameric Con A to mannose-containing receptors was required for the induction of cell death. DNA fragmentation was observed by both laser flow cytometry and electrophoresis in Con A-stimulated T cells and non-T cells. This indicated that the mechanism of induction of apoptosis with Con A is not necessarily TCR-dependent. Con A induced tyrosine phosphorylation of a number of proteins in various types of cells. Interestingly, phosphorylation of the 40 kDa protein developed only in the thymocytes and spleen cells that contain T cells, whereas phosphorylation of the 80 and 120 kDa proteins appeared in both T cells and non-T cells. These results suggested that the Con A-induced apoptosis of T cells and non-T cells involves different but possibly mutually related protein tyrosine phosphorylation-linked signals.
Department of Medical Technology, Nagoya University School of Health Sciences, Aichi, Japan.
F
F
Nagase
T
T
Abo
K
K
Hiramatsu
S
S
Suzuki
J
J
Du
I
I
Nakashima
D000818:Animals; D017209:Apoptosis; D001854:Bone Marrow Cells / Q000378:metabolism; D003208:Concanavalin A / Q000494:pharmacology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
D011506:Proteins; D003208:Concanavalin A; D019000:Phosphotyrosine