Ribosomal protein RPSA is a promising target for the prevention of Streptococcus suis serotype 2

Area of Science:

• Veterinary Microbiology
• Immunology
• Infectious Diseases

Background:

• Streptococcus suis serotype 2 (SS2) is a major zoonotic pathogen affecting both humans and animals.
• Ribosomal protein S1 (RPSA) is a critical virulence factor for SS2, promoting host cell adhesion and blood-brain barrier penetration.

Purpose of the Study:

• To develop and characterize a monoclonal antibody against SS2 RPSA.
• To evaluate the therapeutic and protective potential of anti-RPSA monoclonal antibody and RPSA-based subunit vaccine against SS2 infection.

Main Methods:

• Recombinant SS2 RPSA protein was expressed and used to immunize BALB/c mice.
• A high-affinity monoclonal antibody (mAb-RPSA-5E2) was produced.
• Antibacterial activity of mAb-RPSA-5E2 was assessed in vitro.
• Therapeutic efficacy of mAb-RPSA-5E2 was evaluated in SS2-challenged mice.
• Immunoprotective effects of an SS2-RPSA subunit vaccine were assessed in mice.

Main Results:

• The anti-RPSA monoclonal antibody (mAb-RPSA-5E2) demonstrated potent in vitro antibacterial activity, inhibiting SS2 proliferation.
• Treatment with mAb-RPSA-5E2 significantly reduced mortality rates in SS2-infected mice.
• Pathological damage in lung and brain tissues was alleviated by mAb-RPSA-5E2 treatment.
• The SS2-RPSA subunit vaccine conferred significant protection against SS2 infection in mice.

Conclusions:

• RPSA is a viable target for developing therapeutic biologics against SS2.
• The RPSA protein holds promise as a component of an effective SS2 subunit vaccine.
• Monoclonal antibody therapy targeting RPSA offers a potential strategy for treating SS2 infections.