Anti-trypanosoma cruzi recombinant antibodies with partial agonist effects on cardiac receptors

SMULSKI CR; GRIPPO VANINA; VIVIAN LABOVSKY; G. V. LEVY; ANSALDI S; GÓMEZ KA; LEVIN MJ

Congreso; XL Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2004

Sera from patients with chronic Chagas´ Heart Disease (cChHD) present antibodies directed to the carboxyl terminal regions of the Trypanosoma cruzi ribosomal P2 protein, defined by the epitope named R13 (EEEDDDMGFGLFD). These antibodies have the ability to induce chronotropic alterations in cardiomiocytes cultures due to the cross reactivity with the acidic regions of the second intracellular loop of the cardiac beta-1 adrenergic (BAR) and muscarinic cholinergic receptors. Mice immunization with recombinant TcP2â protein allowed us to obtain an anti-R13 monoclonal antibody, called 17.2 that proved to have functional effects on cardiac rhythm upon passive transfer. Anti-R13 svFc derived from a cChHD combinatorial antibody library and from 17.2 monoclonal antibody producing cells (APC) have been obtained and characterized. Recombinant svFc constructs derived from 17.2 APC, and expressed in a pHEN 2 vector recognized the 5 parasite ribosomal P proteins, bound to ribosomes of fixed parasite cells, cross-reacted with the B1-AR of transfected CHOK1 cells inducing an increase in cAMP levels, and bound to their surface as assessed by indirect immunofluorescence. Passive transfer of this recombinant antibody to naïve mice provoked arrhythmias in recipients heart, as recorded by electrocardiograms. These functional effects are currently under pharmacological characterization.