This study evaluated the immunogenicity of the Bacillus Calmette-Guérin (BCG) vaccine in a guinea pig model to refine preclinical assessment methods. 24 guinea pigs were divided into four groups for immunohistochemical, histopathological, and molecular analyses, including qRT-PCR and ELISA. The ELISA results revealed significant elevations in interleukin 2 (IL-2), interferon-gamma (IFN- ), and tuberculosis-specific antibodies in vaccinated guinea pigs, particularly γ notable after 6 weeks. Although lung cytokine levels remained unchanged, spleen gene expression showed significant differences in interleukin-17, interleukin-12, interleukin-1β, and C-X-C motif chemokine ligand 10 after 6 weeks. Immunohistochemistry revealed peak IL-2 expression at 8 weeks and significant IFN-γ and TNF-α expression at 6 weeks. This study confirmed the effectiveness of BCG vaccine in guinea pigs, providing crucial insights for future tuberculosis vaccine development and standardizing immune response indicators.

INTRODUCTION
MATERIALS AND METHODS
    Animals
    BCG culture and immunization
    Cellular immune marker (IL-2, IFN-γ) test
    Measurement of serum IgG antibodies using ELISA
    Real-Time PCR
    Immunohistochemistry
    Statistical analysis
RESULTS
    Effect of BCG immunization on IL-2, IFN-γ, andPPD-Specific antibodies in guinea pig serum
    Subsection comparative analysis of cytokine andchemokine gene expression changes in the guineapig lungs and spleen
    Immunohistochemical analysis of IL-2, TNF-α, andIFN-γ positive cells in guinea pig lung and spleen
DISCUSSION
ETHICS STATEMENT
ACKNOWLEDGEMENTS
CONFLICT OF INTEREST STATEMENT
REFERENCES

• In-Ohk Ouh(Division of Vaccine Development Coordination, Center for Vaccine Research National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, Korea)
• Min Jung Kim(College of Veterinary, Gyeongsang National University, Gazwa Jinju, 52828, Korea)
• Kwang wook Kim(Division of Vaccine Development Coordination, Center for Vaccine Research National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, Korea)
• Hee ji Lim(Division of Vaccine Development Coordination, Center for Vaccine Research National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, Korea)
• Ye Jin Yang(College of Veterinary, Gyeongsang National University, Gazwa Jinju, 52828, Korea)
• Hu-Jang Lee(College of Veterinary, Gyeongsang National University, Gazwa Jinju, 52828, Korea)
• Woo H. Kim(College of Veterinary, Gyeongsang National University, Gazwa Jinju, 52828, Korea)
• Phil-Ok Koh(College of Veterinary, Gyeongsang National University, Gazwa Jinju, 52828, Korea)
• Seo Young Moon(Division of Vaccine Development Coordination, Center for Vaccine Research National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, Korea)
• Kyoung Hwa Choi(Division of Vaccine Development Coordination, Center for Vaccine Research National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, Korea)
• Yoo-Kyoung Lee(Division of Vaccine Development Coordination, Center for Vaccine Research National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, Korea) Corresponding author
• Kwang Il Park(College of Veterinary, Gyeongsang National University, Gazwa Jinju, 52828, Korea) Corresponding author