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Updated: Feb 16, 2026
Separation and Fractionation of Cell Wall and Cell Membrane Proteins from Mycobacterium tuberculosis for Downstream Protein Analysis
Published on: September 26, 2025
Characterization of plasma proteins in children of different Mycobacterium tuberculosis infection status using
Jieqiong Li1,2,3,4, Lin Sun1,2,3,4, Fang Xu1,2,3,4
1Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
Abstract:
Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is an infectious disease found worldwide. Children infected with MTB are more likely to progress to active TB (ATB); however, the molecular mechanism behind this process has long been a mystery. We employed the label-free quantitative proteomic technology to identify and characterize differences in plasma proteins between ATB and latent TB infection (LTBI) in children. To detect differences that are indicative of MTB infection, we first selected proteins whose expressions were markedly different between the ATB and LTBI groups and the control groups (inflammatory disease control (IDC) and healthy control (HC) groups). A total of 521 proteins differed (> 1.5-fold or < 0.6-fold) in the LTBI group, and 318 proteins in the ATB group when compared with the control groups. Of these, 49 overlapping proteins were differentially expressed between LTBI and ATB. Gene Ontology (GO) analysis revealed most proteins had a cellular and organelle distribution. The MTB infection status was mainly related to differences in binding, cellular and metabolic processes. XRCC4, PCF11, SEMA4A and ATP11A were selected and further verified by qPCR and western blot. At the mRNA level, the expression of XRCC4, PCF11and SEMA4A presented an increased trend in ATB group compare with LTBI. At the protein level, the expression of all these proteins by western blot in ATB/LTBI was consistent with the trends from proteomic detection. Our results provide important data for future mechanism studies and biomarker selection for MTB infection in children.
Insights
This study identifies key plasma proteins that differ between active tuberculosis (ATB) and latent tuberculosis infection (LTBI) in children. These findings offer insights into the molecular mechanisms driving TB progression in pediatric patients.
Area of Science:
- Pediatric Infectious Diseases
- Proteomics
- Molecular Mechanisms of Disease
Background:
- Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is a global infectious disease.
- Children with MTB infection have a higher risk of progressing to active TB (ATB), but the underlying molecular mechanisms remain unclear.
Purpose of the Study:
- To identify and characterize differences in plasma proteins between children with ATB and latent TB infection (LTBI) using label-free quantitative proteomics.
- To uncover molecular distinctions indicative of MTB infection progression in pediatric populations.
Main Methods:
- Label-free quantitative proteomic analysis of plasma samples from children with ATB, LTBI, inflammatory disease control (IDC), and healthy controls (HC).
- Differential protein expression analysis (fold change > 1.5 or < 0.6) to identify proteins distinguishing infection states.
- Gene Ontology (GO) analysis to understand protein functions and distributions.
- Validation of selected proteins (XRCC4, PCF11, SEMA4A, ATP11A) using quantitative PCR (qPCR) and western blot.
Main Results:
- 49 overlapping proteins were differentially expressed between the ATB and LTBI groups.
- Proteins identified were primarily involved in cellular, organelle, binding, and metabolic processes.
- mRNA and protein levels of XRCC4, PCF11, and SEMA4A showed increased trends in the ATB group compared to the LTBI group, consistent with proteomic findings.
Conclusions:
- This study provides a comprehensive proteomic profile differentiating active and latent TB infection in children.
- The identified proteins, particularly XRCC4, PCF11, and SEMA4A, represent potential biomarkers for monitoring MTB infection status and progression in pediatric TB.
- These findings contribute valuable data for future research into the molecular pathogenesis of pediatric TB.
