These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Cholera toxin inhibits interleukin-2-induced, but enhances pertussis toxin-induced T-cell proliferation: regulation by cyclic nucleotides.
    Author: Maghazachi AA.
    Journal: Immunology; 1992 Jan; 75(1):103-7. PubMed ID: 1311282.
    Abstract:
    To understand the signals transmitted by interleukin-2 (IL-2) during T-cell proliferation, the effect of this cytokine was compared to the bacterial product pertussis toxin (PT). Both IL-2 and PT induced the incorporation of [3H]thymidine into T cells. Cholera toxin (CT) inhibited IL-2-induced, but enhanced PT-induced T-cell proliferation. The effect of CT is mimicked by the cyclic AMP (cAMP) analogue 2'-O-dibutyryladenosine 3':5'-cyclic monophosphate (dicAMP) or by the phosphodiesterase inhibitors isobutylmethylxanthine and aminophylline. Measurement of the intracellular level of cAMP showed that CT enhanced this level during both IL-2 or PT incubation with T cells. To delineate the differential effects of cAMP on IL-2 versus PT activity, it was observed that the blocker of intracellular calcium (TMB8), or the guanosine triphosphate (GTP) analogue (GTP gamma S) inhibited both PT and IL-2 activities, whereas the protein kinase C (PKC) inhibitor (H7) was without effect for both stimuli. Further experiments showed that both IL-2 and PT stimulate the endogenous level of cGMP and that CT enhanced this level following PT activation, but reduced it following IL-2 activation of T cells. Hence, there is a major difference between IL-2 and PT activation of T cells in as far as their susceptibility to treatment with cholera toxin is concerned. Furthermore, an increase of cGMP level resulted in the enhancement of proliferation, whereas a decrease in cGMP level resulted in the inhibition of proliferation.
    [Abstract] [Full Text] [Related] [New Search]