STUDY OF BIOLOGICAL ACTIVITY OF DELETION VARIANTS OF FLAGELLIN, THE TLR5 AGONIST

MORENO, GRISELDA; BIEDMA, MARINA; ROSSI, ANDRÉS; BLANCÁ, BRUNO; TABAREAU, JULIEN; ROMANÍN, DAVID; BERGUER, PAULA; SIRARD, JEAN CLAUDE; RUMBO, MARTÍN

Mar del Plata

Congreso; Reunión Conjunta 2014 entre la Sociedad Argentina de Investigación Clínica (SAIC) y la Sociedad Argentina de Inmunología (SAI); 2014

SAIC-SAI

Activation of Toll-like receptors (TLRs) results in recruitment of immune cells to the site of infection and antigen presenting cells activation and maturation, promoting the generation of a strong adaptive immune response. Consequently, TLR ligands have adjuvant properties and some of them are already used in commercial vaccines. TLR5 has a widespread distribution in mucosal epithelia and its ligand, flagellin, has been proposed as mucosal adjuvant. Flagellin includes four domains, D0, D1, D2 y D3; D0 and D1 contains the TLR5 binding sites, whereas D2 and D3 contain the main antigenic sites of the molecule. However, the contribution of different regions of D1, D2 and D3 to TLR5 activation has not been fully explored. In the present work, we used 7 different flagellin deletion variants affecting different domains: FliC WT (no deletion), FliC Δ200-369, FliC Δ161-405, FliC Δ100-405 6H, FliC Δ174-400, FliC Δ174-400 6H, FliC Δ138-405 6H. Our aim was to analyze the capacity to activate TLR5 of these different variants using a TLR5-responsive reporter cellular system (Caco2-CCL20- luciferase). Furthermore, the structural properties of the different variants were analyzed by circular dichroism (CD). In spite tha t all variants have intact TLR5 binding site, we found that the deletions affect differentially the capacity to trigger TLR5. FliC Δ200-369 has the same capacity to activate TLR5 than the wild type variant, whereas other deletions affected significantly this activity (p