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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution, density, and capping of the T cell antigens W3/13, W3/25, and Thy-1 were studied in lymphocytes of young (3 to 4 mo) and aged (greater than or equal to 27 mo) Brown Norway (BN) rats. The total number of W3/13, W3/25, and Thy-1 positive cells and the percentage of Thy-1 positive cells are reduced in the spleens and lymph nodes of aged rats. Analysis of spleen and lymph node cells in a fluorescence-activated cell sorter indicated that with ageing there is a loss of moderately and brightly stained W3/13 and W3/25 positive cells. The density of W3/13, W3/25, and Thy-1 is reduced on spleen and lymph node cells of old rats. The rate of capping of all 3 molecules is diminished on "old" cells. Colchicine treatment of young cells enhanced capping of all 3 molecules and allowed capping of W3/13 by a single ligand. However, capping on "old" lymphocytes was not affected by colchicine treatment. Cytochalasin D inhibited capping to the same extent on young and "old" cells. These results suggest that the membrane composition and cytoskeleton are altered in T lymphocytes of aged rats.
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PMID:T lymphocytes of young and aged rats. I. Distribution, density, and capping of T antigens. 697 6

Colchicine inhibits cell microtubule assembly by binding to and preventing the polymerization of tubulin monomers. Although there are data to indicate that colchicine inhibits a variety of cell-mediated immune responses, the effects and mechanisms of inhibiting cell microtubule assembly on the alloimmune response have not been thoroughly investigated. It has recently been shown that colchicine prevents acute rejection and promotes the long-term survival of rat renal allografts. In this study, the effects and mechanisms of inhibiting cell microtubule assembly by colchicine on the alloimmune response in vitro and in vivo were examined. First, the effects of colchicine on T lymphocyte response to alloantigen in vitro were tested. In the standard one-way mixed lymphocyte response (MLR), responder Lewis rat lymph node cells were cultured with irradiated Brown-Norway stimulators. Colchicine inhibited the MLR in a dose-dependent manner, with 100% inhibition at a concentration of 25 ng/mL (6.25 x 10(-8) M) and 50% inhibition at a concentration of approximately 5 to 10 ng/mL. Colchicine also inhibited the generation of cytotoxic T lymphocytes as well as cytotoxic T cell effector function in vitro in a dose-dependent fashion. Second, detailed immunohistologic studies of renal allografts harvested from unmodified control (acutely rejecting) and colchicine-treated rats (Day 15 or 30) were performed. These studies showed that grafts from colchicine-treated animals had significantly fewer mononuclear cell infiltrates and less edema, and moderately decreased deposition of immunoglobulin M, C3, and fibrin, as compared with acutely rejecting control grafts.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Blocking cell microtubule assembly inhibits the alloimmune response in vitro and prolongs renal allograft survival by inhibition of Th1 and sparing of Th2 cell function in vivo. 770 79

Colchicine, with its immunosuppressive properties, has been used with beneficial effects in autoimmune diseases. Whether colchicine, by virtue of the above properties, could attenuate the process of kidney allograft rejection in the rat is investigated in this report. Untreated Lewis rats (N = 6) given an incompatible kidney allograft from Brown-Norway rats rejected the graft within 12 days. Colchicine at a daily ip dose of 40 (N = 6) or 10 (N = 4) micrograms/kg promoted long-term survival (> 170 days) of major histocompatibility complex-incompatible kidney grafts. Animals (N = 4) given 4 micrograms of colchicine per kilogram had a graft failure within 10 days. Experiments have also been performed to evaluate the effect of colchicine withdrawal at different time intervals from transplantation on subsequent allograft survival. Colchicine (40 micrograms/kg per day ip) was given for 12, 6, or 1 mo or for 15 days to an additional four groups of six animals each without any other immunosuppressants. The withdrawal of colchicine did confer long-term inhibition of the immune system in animals treated for at least 1 mo, as documented by a graft survival of more than 80 days. By contrast, those animals who discontinued colchicine after only 15 days of treatment had graft rejection within the next 8 days. Mixed lymphocyte culture experiments showed a significant (P < 0.01) reduction of the proliferation of peripheral blood lymphocytes taken from all groups of animals 30 days after colchicine withdrawal when challenged with Brown-Norway lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Colchicine allows prolonged survival of highly reactive renal allograft in the rat. 813 Mar 55