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Updated: May 23, 2025
Protective Efficacy and Pulmonary Immune Response Following Subcutaneous and Intranasal BCG Administration in Mice
Published on: September 19, 2016
Evaluating Bacillus Calmette-Guérin Polysaccharide Nucleic Acid as an Adjuvant for Influenza Vaccines in Mice
Sijing Yan1, Fan Yang1, Jia Ji1
1State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Background:
To enhance influenza vaccine efficacy, it is essential to investigate new adjuvants that are both safe and effective. In a recent study utilizing a mouse model, Bacillus Calmette-Guérin polysaccharide nucleic acid (BCG-PSN) emerged as a promising candidate vaccine adjuvant.
Methods:
This study evaluated the immunomodulatory effects of BCG-PSN on influenza vaccines hemagglutinin antigen and aluminum adjuvant as controls. Mice were immunized with H1N1 antigen and adjuvants, and serum antibody levels were measured using hemagglutination inhibition, enzyme-linked immunosorbent assay, and microneutralization assays. Flow cytometry and enzyme-linked immunospot assays assessed T cell phenotypes and cytokine expression. The protective effects were tested through challenge experiments, and the adjuvants were further evaluated in a quadrivalent seasonal influenza vaccine.
Results:
BCG-PSN adjuvant exhibited favorable safety profiles and demonstrated an ability to elevate total antibody titers, particularly enhancing neutralizing antibody production when co-administered with the H1N1 antigen. BCG-PSN increased cytokine levels and the proportion of CD8+ T lymphocytes, indicating its capacity to enhance cellular immunity. Upon viral challenge in mice, BCG-PSN mitigated the production of inflammatory factors and reduced lung pathology, effectively protecting the mice. Furthermore, BCG-PSN displayed heightened immunogenicity against a mixture of four antigens.
Conclusions:
BCG-PSN is a reliable and efficient adjuvant for influenza vaccines, holding promise for enhancing vaccine efficacy and increasing immune responses.
