Protection against bubonic and pneumonic plague with a single dose microencapsulated sub-unit vaccine

Area of Science:

• Bacteriology
• Immunology
• Vaccine Development

Background:

• Yersinia pestis causes plague, a severe infectious disease.
• Effective vaccines are crucial for controlling plague outbreaks.
• Current plague vaccines often require multiple doses.

Purpose of the Study:

• To evaluate the protective efficacy of microencapsulated Yersinia pestis antigens (Caf1 and LcrV).
• To assess immune responses induced by single-dose parenteral and aerosol immunization.
• To determine if intranasal administration can elicit protective immunity.

Main Methods:

• Recombinant Caf1 and LcrV antigens were encapsulated in polymeric microspheres.
• Mice were immunized once via intranasal or intramuscular routes with blended microspheres.
• Immune responses were assessed by serum IgG levels, cytokine secretion (Elispot), and T-cell proliferation.
• Mice were challenged with virulent Yersinia pestis to evaluate protection.

Main Results:

• Single-dose immunization with microencapsulated antigens induced high levels of serum IgG.
• Both Th1 and Th2 cytokines were activated, and spleen cells proliferated in response to antigens.
• Intranasal immunization provided strong systemic and local immune responses.
• Mice immunized via both routes were protected against virulent plague challenge.

Conclusions:

• Single administration of microencapsulated Caf1 and LcrV antigens provides effective protection against plague.
• Intranasal immunization is a viable non-invasive route for inducing protective immunity.
• Controlled antigen release from microspheres enables single-dose vaccination for plague.