%0 Journal Article
%A Martínez Florensa, Mario
%A Català, Cristina
%A Velasco de Andrés, María
%A Cañadas Benito, Olga
%A Fraile Ágreda, Víctor
%A Casadó Llombart, Sergi
%A Armiger Borràs, Noelia
%A Consuegra Fernández, Marta
%A Casals Carro, María Cristina
%A Lozano, Francisco
%T Conserved bacterial-binding peptides of the scavenger-like human lymphocyte receptor CD6 protect from mouse experimental sepsis
%D 2018
%@ 1664-3224
%U https://hdl.handle.net/20.500.14352/93723
%X Sepsis is an unmet clinical need constituting one of the most important causes of death worldwide, a fact aggravated by the appearance of multidrug resistant strains due to indiscriminate use of antibiotics. Host innate immune receptors involved in pathogen-associated molecular patterns (PAMPs) recognition represent a source of broad-spectrum therapies alternative or adjunctive to antibiotics. Among the few members of the ancient and highly conserved scavenger receptor cysteine-rich superfamily (SRCR-SF) sharing bacterial-binding properties there is CD6, a lymphocyte-specific surface receptor. Here, we analyze the bacterial-binding properties of three conserved short peptides (11-mer) mapping at extracellular SRCR domains of human CD6 (CD6.PD1, GTVEVRLEASW; CD6.PD2 GRVEMLEHGEW; and CD6.PD3, GQVEVHFRGVW). All peptides show high binding affinity for PAMPs from Gram-negative (lipopolysaccharide; Kd from 3.5 to 3,000 nM) and Gram-positive (lipoteichoic acid; Kd from 36 to 680 nM) bacteria. The CD6.PD3 peptide possesses broad bacterial-agglutination properties and improved survival of mice undergoing polymicrobial sepsis in a dose- and time-dependent manner. Accordingly, CD6.PD3 triggers a decrease in serum levels of both pro-inflammatory cytokines and bacterial load. Interestingly, CD6.PD3 shows additive survival effects on septic mice when combined with Imipenem/Cilastatin. These results illustrate the therapeutic potential of peptides retaining the bacterial-binding properties of native CD6.
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