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The following is a summary of “Serological responses to target Streptococcus pyogenes vaccine antigens in patients with proven invasive beta-haemolytic streptococcal infections,” published in the October 2024 issue of Infectious Disease by Langworthy et al.
The increasing frequency of invasive beta-haemolytic streptococcal (iBHS) infections has led to the investigation of vaccination as a preventive measure for the population with infections.
Researchers conducted a retrospective study to evaluate the potential cross-species immunity of a Streptococcus pyogenes; Strep A vaccine against Streptococcus dysgalactiae subspecies equisimilis (SDSE) and Streptococcus agalactiae (GBS), which could enhance its benefits.
They analyzed the patients with iBHS infections due to Strep A, SDSE, or GBS. Antibody responses to 6 Strep A candidate antigens were measured in acute and convalescent sera. A serological response was defined as an increase of > 0.2 log10 arbitrary units/mL (AU/mL).
The results showed that 67 participants were enrolled, with 33 included in the final analysis (12 Streptococcus pyogenes, 11 SDSE, and 10 GBS). Participants with Streptococcus pyogenes had significant median (IQR) serological responses to all tested antigens (median >0.2 log10 difference between acute and convalescent samples; P<0.05). Those with SDSE had tremendous responses streptolysin-O (median 0.65 [0.36-1.67], P=0.004), S. pyogenes adhesion and division protein (0.68 [0.36-1.63], P=0.005), and C5a peptidase (ScpA; 0.30 [0.23-1.06], P=0.004) while, GBS was only significant for ScpA (0.34 [0.08-0.52], P=0.05).
Investigators concluded the patients with Strep A infection developed a strong antibody response to 6 non-M protein vaccine antigens, while similar responses to C5a peptidase in patients with SDSE and GBS infections, suggesting the potential for cross-species protection.
Source: academic.oup.com/jid/advance-article-abstract/doi/10.1093/infdis/jiae496/7816300
