Bacterium-like particles obtained from the respiratory commensal bacteria Corynebacterium pseudodiphtheriticum improve the immune response to chimeric pneumococcal antigen

ORTIZ MOYANO RAMIRO ; RAYA-TONETTI FERNANDA; MELNIKOV, VYACHESLAV; SUVOROV, ALEXANDER; VIZOSO-PINTO MARIA GUADALUPE; KITAZAWA HARUKI; ALVAREZ SUSANA; VILLENA JULIO

San Miguel de Tucuman

Congreso; LXVII Reunión Científica Anual de la Sociedad Argentina de Inmunología.; 2019

Sociedad Argentina de Inmunología (SAI)

Previously, it was demonstrated that the nasal priming of mice with viable and non-viableCorynebacterium pseudodiphtheriticum 090104 (Cp) differentially modulated the respiratoryinnate immune response against Streptococcus pneumoniae (Sp). The aim of this work was tostudy whether the nasal immunization with the recombinant chimeric pneumococcal proteinPSPF (PsaA-Spr1875-PspA-FliC) and viable Cp (VCp) or bacterium-like particles obtained fromCp (BPCp) are able to induce specific respiratory and systemic immune responses and improveresistance to Sp infection. Swiss-albino mice (6-weeks-old) were nasally primed with PSPF,PSPF+VCp or PSPF+BPCp on days 0, 14 and 28 (20 μg of PSPF, 108 VCp cells or BPCp). Five daysafter the last immunization, the levels of anti-PSPF IgM, IgG and IgA antibodies in bronchoalveolarlavage (BAL) and serum, and the resistance to pneumococcal infection weredetermined. The nasal immunization with PSPF induced specific IgM, IgA and IgG antibodies inthe serum and BAL, and reduced lung bacterial counts and avoided dissemination ofpneumococci into the blood after the challenge with Sp serotypes 6B or 19F. Mice immunizedwith PSPF+VCp or PSPF+BPCp showed significantly higher levels of respiratory and serumantibodies, and lower counts of serotypes 6B and 19F in lungs than the PSPF group. PSPF+BPCpwas more efficient than PSFP+VCp to improve the humoral immunity (p