J8-K4S2

J8-K4S2 is an investigational peptide-based vaccine candidate designed to protect against Group A Streptococcus (Strep A, Streptococcus pyogenes) infections. The vaccine consists of a synthetic peptide (J8), derived from a highly conserved region of the M protein of Strep A, conjugated to K4S2, a protein subunit from SpyCEP (an IL-8 protease associated with neutrophil chemoattraction). Both components are individually conjugated to cross-reacting material 197 (CRM197), a non-toxic mutant of diphtheria toxin used as a carrier protein. The primary mechanism is to induce an immune response targeting both the M protein and SpyCEP, aiming to prevent Strep A infection and its complications such as rheumatic fever and post-streptococcal glomerulonephritis. J8-K4S2 is currently being evaluated in phase 1 clinical trials for safety and immunogenicity in healthy adults[1][3][5].