ALVEOLAR MACROPHAGES DEPLETION AFFECTS THE ABILITY OF DOLOSIGRANULUM PIGRUM 040417 TO PROTECT INFANT MICE AGAINST PNEUMOCOCCAL INFECTION

RAYA-TONETTI, FERNANDA; ORTIZ MOYANO, RAMIRO; VIZOSO-PINTO, M. GUADALUPE; VILLENA, JULIO

Buenos Aires

Congreso; Reunión Conjunta SAIC. SAI. AAFE. NANOMED-AR; 2021

SAIC. SAI. AAFE. NANOMED-AR

ALVEOLAR MACROPHAGES DEPLETION AFFECTSTHE ABILITY OF DOLOSIGRANULUM PIGRUM040417 TO PROTECT INFANT MICE AGAINST PNEUMOCOCCALINFECTIONFernanda Raya-Tonetti 1, Ramiro Ortiz Moyano 1, Mikado Tomokiyo2; Vyacheslav Melnikov 3, Haruki Kitazawa 2,4, JulioVillena 1,21 Laboratory of Immunobiotechnology, Reference Centre forLactobacilli (CERELA-CONICET), Tucuman, Argentina.2 Food and Feed Immunology Group, Laboratory of AnimalProducts Chemistry, Graduate School of Agricultural Science,Tohoku University, Sendai, Japan.3 Gabrichevsky Research Institute of Epidemiology and Microbiology,Russia4 Livestock Immunology Unit, International Education and ResearchCenter for Food and Agricultural Immunology (CFAI),Graduate School of Agricultural Science, Tohoku University,Sendai, Japan.Previously, we demonstrated that the nasal administration of therespiratory commensal bacterium Dolosigranulum pigrum 040417(Dp04) to infant mice differentially modulates the respiratory immuneresponse triggered by Toll-like receptor (TLR)-2 activation, increasingthe resistance to Streptococcus pneumoniae (Sp) infection. Thenasal priming with Dp04 reduced pneumococcal counts in lung andblood and diminished the levels of lung injury biomarkers. In thiswork, we aimed to characterize the role of alveolar macrophages(AM) on the immunomodulatory properties of Dp04 in the context ofpneumococcal infection. In the first set of experiments, mice werenasally stimulated with Dp04 (108 cells/mouse/day) for 5 consecutivedays and then challenged with 106 CFU of Sp. Variations innumbers and functionality of resident AM in broncho-alveolar lavage(BAL) samples were evaluated. The number of activated CD11c+SiglecF+MHC-IIhi AM was significantly increased after Sp challenge inmice primed with Dp04 than in controls (p