BACTERIUM-LIKE PARTICLES DERIVED FROM THE RESPIRATORY COMMENSAL BACTERIA CORYNEBACTERIUM PSEUDODIPHTHERITICUM 090104 AS A PROMISING MUCOSAL ADJUVANT

ORTIZ MOYANO, RAMIRO; RAYA TONETTI, FERNANDA; SACUR, JACINTO; TOMOKIYO, MIKADO; VYACHESLAV MELNIKOV; ALVAREZ, SUSANA; KITAZAWA, HARUKI; VIZOSO PINTO, MARIA GUADALUPE; VILLENA, JULIO

Congreso; Reunión Anual de Sociedades de Biociencias 2021; 2021

Corynebacterium pseudodiphtheriticum is a Gram-positive bacterium that is part of the nasopharyngeal microbiota. This bacteriumwas shown to prevent the colonization of the respiratory mucosaby pathogenic bacteria including Streptococcus pneumoniae (Sp).We recently demonstrated that C. pseudodiphtheriticum 090104(Cp), when nasally administered to mice; differentially modulatedthe respiratory immune responses triggered by TLR2 and improvedthe resistance to pneumococcal pneumonia. We also reported thatbacterium-like particles derived from Cp (BPCp) had the ability tomodulate the innate respiratory immunity. These results allowed usto hypothesize that Cp or BPCp could be used as mucosal adjuvants to enhance the respiratory adaptive immunity. In this work,infant Swiss-albino mice were nasally immunized with 6.25 pg ofPneumovax23® vaccine (PV), PV plus Cp (108 CFU) or PV plusBPCp at days 0, 14 and 28. Seven days after the last immunizationsamples of bronco-alveolar lavages (BAL) and serum were collectedfor specific antibodies determinations. In addition, immunized micewere challenged with Sp serotypes 6B or 19F (106 CFU) and theresistance to the infection was evaluated 2 days after the challenge.Mice in the PV+Cp and PV+BPCp groups had significantly higherlevels of BAL anti-Sp IgG and IgA (p