Abstrakt

Vaccine against S. pyogenes

Luiza Guilherme

 StreptInCor, a candidate vaccine against S. pyogenes is based on protective 55 amino acids residues of C-terminal portion of the M protein. Experimental assays have demonstrated that the StreptInCor peptide induces high titers of opsonic and neutralizing and protective antibodies in outbred immunized mice. Using HLA class II transgenic mice, it was possible to evaluate the immunogenicity and safety of the StreptInCor vaccine epitope for a period of one year. Specific and non-auto reactive antibodies were produced as well as no autoimmune or pathological reactions were observed in the heart or other organs of these animals. We also performed several studies in minipigs in order to evaluate the immune response and safety by submitting these animals to echocardiogram examination before immunization and after the four doses treatment. No alterations were observed. In addition, both repeated intramuscular-dose toxicity tests (28 days) with four doses and echocardiography procedure in mini pigs after 28 days were performed. No harmful effects to the tissues and organs studied were observed indicating that the vaccine is safe. StreptInCor vaccine also induces regulatory T cells (Treg) that strongly indicate that the vaccine peptide may have therapeutic potential to control both inflammatory and autoimmune response in RF/RHD patients. Streptococcus pyogenes causes severe, invasive infections such as the sequelae associated with acute rheumatic fever, rheumatic heart disease, acute glomerulonephritis, uncomplicated pharyngitis, and pyoderma. Efforts to produce a vaccine against S.pyogenes began several decades ago, and different models have been proposed.