Work

Prior appendectomy attenuates the immune protective efficacy of BCG vaccination against Mycobacterium tuberculosis infection

Year: 2025

Type: article

Abstract: Cecal appendix is a unique niche for commensal bacteria, and has been considered the primary site for immunoglobulin A production. Yet its immune function in anti-infection immunity has not been fully understood. In order to elucidate whether cecal patch (CeP), the murine version of appendix, would influence the immune response induced by Mycobacterium tuberculosis ( M. tb ) and the vaccine effect of Bacillus Calmette-Guérin (BCG), BALB/c mice at 4 weeks of age received appendectomy or sham operation and recovered for 2 weeks before intranasal infection with 2 × 10 7 CFU Mycobacterium tuberculosis H37Ra. Appendectomy of mice led to a reduction in lung macrophage numbers 7 days post infection (p. i.), and aggravated lung immunohistopathology 4 weeks p. i.. Appendectomized mice vaccinated with 5 × 10 6 CFU BCG exhibited attenuated BCG-specific serum IgG, reduced lung/splenic IFN-γ + T response, and weakened T proliferation and cytotoxicity, and eventually worsened lung pathology compared to sham operated mice. Mechanistically, we found that appendectomized mice at a young age (4 weeks) had an attenuated maturation of mesenteric lymph node (MLN) conventional dendritic cells (cDCs), which accounted for the impaired systemic IFN-γ + T response and cytotoxicity against M. tb . Our data suggest that intact appendix maintain intestinal DC maturation and systemic Th1 induction against M. tb and has an assistant role in increasing immune efficiency of BCG vaccine. • We demonstrate a new function of cecal patch/appendix to promote immune response after M. tuberculosis infection. • Intact cecal patch/appendix is critical for the protective efficacy of Bacillus Calmette-Guérin (BCG) vaccination. • Mechanistically, cecal patch/appendix stimulate intestinal dendritic cells and systemic Th1 induction after BCG vaccination.

Source: Immunobiology

DOI: 10.1016/j.imbio.2025.153106

Authors: Huirong Huang, Wei Xu, Sidong Xiong

Institution: Soochow University

Language: English

Topic: Tuberculosis Research and Epidemiology

Subfield: Infectious Diseases

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,840