Role of calcium and protein kinase C in the activation of T cells in Takayasu's arteritis.
The roles of protein kinase C and calcium in the T cells of patients suffering from Takayasu's arteritis (TA) in response to the mitogens phorbol-myristate acetate (PMA) and streptococcal antigens have been studied. In TA there was an increased basal activity of protein kinase C (1.074 +/- 0.223 nmoles/mg protein/min) as compared with that of controls (0.570 +/- .12) (p < 0.001). There was 75% translocation from the cytosol to membrane fraction in response to PMA. Intracellular calcium levels showed increased basal levels in TA (177.07 +/- 12.56 nmoles) compared with the controls (112.83 +/- 10.6 nmoles) (p < 0.001) and there was a further rise on stimulation, indicating the T cells were in an activated state. There was a positive correlation between the calcium levels and the activity of protein kinase C (r = 0.71, p < 0.05). Unlike the situation in patients with rheumatic fever, T cells in TA showed no stimulation in response to streptococcal antigens. The low level of cAMP (1.12 +/- 0.169 pmoles/million cells) compared with that of controls (1.4 +/- 0.03) further supports the role of PKC-calcium in the T cell activation process. These findings suggest activation of the PKC-calcium pathway in TA.
Dhar
J
J
Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Ganguly
N K
NK
Kumari
S
S
Sharma
B K
BK
D000293:Adolescent; D000328:Adult; D002118:Calcium / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D008934:Mitogens / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*; D013625:Takayasu Arteritis / Q000097:blood / Q000276:immunology*
D008934:Mitogens; D011493:Protein Kinase C; D002118:Calcium