Respiratory commensal bacteria Corynebacterium pseudodiphthericum and recombinant chimeric pneumococcal protein as novel mucosal vaccine for the prevention of S. pneumoniae infection

FERNANDA RAYA TONETTI; VYACHESLAV MELNIKOV; RAMIRO ORTIZ MOYANO; ALEXANDER SUVOROV; VILLENA, JULIO; VIZOSO-PINTO, MARÍA GUADALUPE; SUSANA SALVA

Congreso; Advanced Course on Mucosal Immunology; 2018

Respiratory tract infections and invasive disease caused by Streptococcus pneumoniae in high-risk groups are a major global health problem. Available human vaccines have reduced immunogenicity and low immunological memory in these populations, as well as high cost as a public health strategy in poor communities. In addition, no single pneumococcal protein antigen has been able to elicit protection comparable to that achieved using protein-polysaccharide conjugate vaccines. In this context, chimeric pneumococcal proteins raise as potential good vaccine candidates because of their simplicity of production and reduced cost. The aim of the work is to evaluate whether the nasal immunization with the recombinant chimeric pneumococcal proteins is able to improve resistance to S. pneumoniae, and whether immunomodulatory lactic acid bacteria (LAB) or commensal respiratory bacteria (CRB) cells fractions could be used as effective mucosal adjuvants. The molecular interactions of immunomodulatory cellular fractions from LAB and CRB with the respiratory immune system will be studied in vitro, using respiratory epithelial cells and alveolar macrophages. In addition, the ability of immunomodulatory LAB and CRB fractions to improve respiratory and systemic immune responses against nasally administered recombinant pneumococcal chimeric antigens will be evaluated in mice models of pneumococcal infection. The project proposes a novel application of immunomodulatory LAB and CRB fractions in the development of new products with immune-enhancing capacity against respiratory pathogens, with broad perspectives of future applications. The development of these adjuvant products and the depth of the basic studies proposed will make an important contribution to scientific knowledge in the area.