Assessment of the Adjuvant Effects of Lentinan on the Tuberculosis Subunit Vaccine BG

TL;DR

This study shows that lentinan, alone or combined with Mn(J), boosts the BG tuberculosis vaccine's effectiveness in rabbits by increasing immune response and reducing bacterial load.

Contribution

The novel contribution is demonstrating lentinan and lentinan/Mn(J) as effective adjuvants for the BG tuberculosis subunit vaccine in an animal model.

Findings

BG–lentinan and BG–lentinan/Mn(J) vaccines significantly increased antigen-specific IgG levels in rabbits.

The BG–lentinan vaccine group showed the lowest bacterial load in nodules after BCG infection.

Both vaccines accelerated the pathological process following BCG infection.

Abstract

Objectives: This study aims to assess the adjuvant effects of lentinan and its combination with Mn(J), a manganese-based colloidal adjuvant, on the BG (fusion protein BfrB-GrpE of Mycobacterium tuberculosis) subunit vaccine. Methods: A rabbit skin infection model was established to evaluate the immune protection conferred by the BG–lentinan vaccine, the BG–lentinan/Mn(J) vaccine, and the Bacillus Calmette-Guérin (BCG) vaccine against tuberculosis. Rabbits were vaccinated at weeks 0, 2, and 4. Six weeks post-vaccination, antigen-specific IgG levels were measured, followed by a BCG skin challenge. Results: Both the BG–lentinan and BG–lentinan/Mn(J) vaccines significantly increased antigen-specific IgG levels against BfrB and GrpE in rabbits (p < 0.05). Furthermore, these vaccines accelerated the pathological process following BCG infection. The bacterial load in nodules was notably reduced, with the BG–lentinan vaccine group exhibiting the lowest levels (p < 0.01). Conclusions: Lentinan and its combined adjuvant, lentinan/Mn(J), significantly enhance the immune response elicited by the BG tuberculosis subunit vaccine, providing effective protection.

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