# Enhanced Glycosylation Caused by Overexpression of Rv1002c in a Recombinant BCG Promotes Immune Response and Protects against Mycobacterium tuberculosis Infection

## TL;DR

A modified BCG vaccine overexpressing Rv1002c boosts immune response and protection against tuberculosis by enhancing glycosylation and macrophage activation.

## Contribution

The study demonstrates that overexpression of Rv1002c in BCG enhances glycosylation and immune protection against tuberculosis.

## Key findings

- rBCG-Rv1002c secretes more glycosylated proteins, enhancing macrophage activation and immune protection against M. tuberculosis.
- rBCG-Rv1002c upregulates immune regulatory molecules, activates the NF-κB pathway, and increases NO and H2O2 release in macrophages.
- Immunization with rBCG-Rv1002c in mice reduces lung bacterial load and histological damage upon M. tuberculosis infection.

## Abstract

Tuberculosis (TB) is a major global health threat despite its virtual elimination in developed countries. Issues such as drug accessibility, emergence of multidrug-resistant strains, and limitations of the current BCG vaccine highlight the urgent need for more effective TB control measures. This study constructed BCG strains overexpressing Rv1002c and found that the rBCG-Rv1002c strain secreted more glycosylated proteins, significantly enhancing macrophage activation and immune protection against Mycobacterium tuberculosis (M. tb). These results indicate that Rv1002c overexpression promotes elevated levels of O-glycosylation in BCG bacteriophages, enhancing their phagocytic and antigenic presentation functions. Moreover, rBCG-Rv1002c significantly upregulated immune regulatory molecules on the macrophage surface, activated the NF-κB pathway, and facilitated the release of large amounts of NO and H2O2, thereby enhancing bacterial control. In mice, rBCG-Rv1002c immunization induced greater innate and adaptive immune responses, including increased production of multifunctional and long-term memory T cells. Furthermore, rBCG-Rv1002c-immunized mice exhibited reduced lung bacterial load and histological damage upon M. tb infection. This result shows that it has the potential to be an excellent candidate for a preventive vaccine against TB.