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; MIKADO TOMOKIYO; VYACHESLAV MELNIKOV ; ALVAREZ, SUSANA; HARUKI KITAZAWA ; MARÍA GUADALUPE VIZOSO-PINTO; VILLENA, JULIO

Buenos Aires

Congreso; Reunión Anual de Sociedades de Biociencias SAIC. SAI. AAFE. NANOMED.ar; 2021

SAI-SAIC

Corynebacterium pseudodiphtheriticum is a Gram-positive bacterium that is part of the nasopharyngeal microbiota. Cp was shown to prevent the colonization of the respiratory mucosa by pathogenic bacteria including Streptococcus pneumoniae (Sp). We recently demonstrated that C. pseudodiphtheriticum 090104 (Cp), when nasally administered to mice; differentially modulated the respiratory immune responses triggered by TLR2 and improved the resistance to pneumococcal pneumonia. We also reported that bacterium-like particles derived from Cp (BPCp) had the ability to modulate the innate respiratory immunity. These results allowed us to 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 of Pneumovax23® vaccine (PV), PV plus Cp (108 CFU) or PV plus BPCp at days 0, 14 and 28. Seven days after the last immunization samples of bronco-alveolar lavages (BAL) and serum were collected for specific antibodies determinations. In addition, immunized mice were challenged with Sp serotypes 6B or 19F (106 CFU) and the resistance to the infection was evaluated 2 days after the challenge. Mice in the PV+Cp and PV+BPCp groups had significantly higher levels of BAL anti-Sp IgG and IgA (p