Characterization of the immune response against Clostridium difficile.

CELANO J; BARBERO AM; HERNÁNDEZ DEL PINO RE; ESTERMANN MA; ERBITI G; BALBI MG; MACHAIN M; PASQUINELLI V

CABA

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

SAIC, SAIB, SAI, SAA, SOCIEDAD ARGENTINA DE BIOFÍSICA (SAB), SOCIEDAD ARGENTINA DE BIOLOGÍA (SAB), SAFE, SAFIS, SAH, SAP

Clostridium difficile is a gram-positive, anaerobic, spore-forming bacteria. C. difficile infection (CDI) is one of the major causes of nosocomial infections. Transmission of C. difficile occurs through the fecal-oral route and the clinic symptoms go from a transitory intestinal colonization to death. The major cause of susceptibility to CDI is the use of antibiotics and the standard method of treatment is the use of antibiotics.Little is known about the role of T cells during CDI. Therefore, and given the pro-inflammatory character of CDI, we studied the innate and adaptive immune response against this pathogen. We stimulated PBMCs from healthy donors with C. difficile extracts, heat in- activated (CD Heat) or inactivated with formaldehyde (CD Formol). First, we evaluated SLAM expression and TNF-a production on monocytes. C. difficile stimulation up-regulated SLAM and TNF-a expression on CD14+ cells, greater effects were observed with the heat inactivated extract.Next, we determined the levels of the pro-inflammatory cytokines, IFN-g and IL-17, and we also evaluated the expression of the costimulatory molecules SLAM, ICOS and PD-1 on CD3+ cells. We found that, both C. difficile extracts, induced IFN-g production (measured by ELISA). Furthermore, we analyzed the IFN-g production by flow cytometry and Real Time PCR. IFN-g expression was higher when PBMCs were stimulated with CD Formol for 5 days. Moreover, more than 50% of IFN-g+ cells were also IL-17􏰀 after 5 days of stimulation with CD Formol. In addition, C. difficile stimulation led to an increase of CD3+PD-1+IFN-g+ and CD3+SLAM+IFN-g+ cells. Our results sug- gest that C. difficile induce a strong pro-inflammatory response and that PD-1 and SLAM could be implicated on the regulation of IFN-g.The study of T response regulation through costimulatory molecules could be crucial for the discovery of new therapeutic targets and biomarkers that could improve the quality of existing treatments and diagnoses.