Allogenic stimulus induces prostaglandin and thromboxane production in T lymphocytes

Prostanoids synthesis in lymphocyte subpopulations by adrenergic and cholinergic receptor stimulation

The release of eicosanoids (PGE2 and TXB2) as a consequence of specific neurotransmitter receptor agonist stimulation is described herein. The differential expression of beta adrenergic and muscarinic cholinergic receptors on sets and subsets of lymphocytes was first identified. Saturation assays with a specific radioligand for beta adrenergic receptors (3H-DHA) showed that B-, T-, T-helper (Th) and T-suppressor/cytotoxic (Ts/c) lymphocyte enriched populations all displayed beta adrenergic receptors. In contrast, when a specific radioligand for muscarinic cholinergic receptors (3H-QNB) was used, B-lymphocytes showed a lack of high-affinity muscarinic cholinergic receptors, while T-lymphocytes expressed them. Ts/c murine lymphocytes had more muscarinic cholinergic receptors than did Th cells. Specific receptor stimulation by the agonist caused a release of different eicosanoids depending on the cell type. Isoproterenol, triggered the release of TXB2 by B and Th-cells, but had no effect on Ts/c-cells. On the other hand, the muscarinic cholinergic agonist, carbachol only induced the release of PGE2 by Ts/c-cells. These results suggest differences in the expression and function of neurotransmitter receptors in sets and subsets of murine lymphocytes regarding the release of eicosanoids.

Antibodies bind and activate beta adrenergic and cholinergic lymphocyte receptors in Chagas' disease

It is demonstrated that murine chagasic IgG and the corresponding F(ab')2 fragments interfere with beta adrenergic and muscarinic cholinergic specific ligand occupancy on T cell-enriched population. From the interaction between chagasic IgG or F(ab')2 with Lyt-1+ cells, an increase in cAMP levels occurs as a consequence of beta adrenergic receptor activation. On the contrary, chagasic IgG or F(ab')2 interactions with Lyt-2+ cells induce an activation of muscarinic cholinergic receptor, leading to an increment in cGMP. Muscarinic cholinergic and beta adrenergic stimulation trigger the release of PGE2 and TXB2, respectively. Lyt-2+ cells treated with chagasic IgG or F(ab')2 are able to decrease the contractility of mouse atria. The same negative inotropic effect is elicited with Lyt-2+ cells from Trypanosoma cruzi-infected mice susceptible to developed myocarditis. The implications of these results in the pathogenesis of Chagas' myocarditis are discussed.