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Separation and Fractionation of Cell Wall and Cell Membrane Proteins from Mycobacterium tuberculosis for Downstream Protein Analysis
Published on: September 26, 2025
Clinical evaluation of the recombinant 38 kDa protein of Mycobacterium tuberculosis
Xiu-Yun He1, Yong-Ai Luo, Xiao-Gang Zhang
1The Second Affiliated Hospital of General Hospital, People's Liberation Army, Beijing, China. xwhe@sohu.com
Abstract:
The diagnosis of tuberculosis remains among public health concerns due to shortcomings of the purified protein derivative (PPD). Recombinant truncated 38 kDa protein (rTPA38) of Mycobacterium tuberculosis was evaluated to screen new tuberculosis-specific tuberculin. 539 patients, 1133 healthy controls, and 55 guinea pigs were recruited to assess their sensitivity and specificity to rTPA38; 221 healthy controls, with negative responses to rTPA38 and PPD, were vaccinated with M. bovis BCG to determine their cross-reactions with M. bovis BCG. The Mantoux technique was adopted to perform skin tests. No difference in the sensitivity of skin tests was detected between rTPA38 and PPD (78.2% vs 83.4%), but there was a significant difference in the specificity of skin tests between rTPA38 and PPD (75.2% vs 47.0%). Compared to PPD, rTPA38 elicited low positive responses for those recruitments vaccinated with M. bovis BCG. The rTPA38 had significant skin reactions in M. tuberculosis-sensitized guinea pigs, and the opposite was true for both M. fortuitum- and M. kansasii-sensitized guinea pigs. These findings indicate that rTPA38 may have potential as a tuberculosis-specific skin test antigen.
Insights
A new tuberculosis skin test antigen, recombinant truncated 38 kDa protein (rTPA38), shows promise. While sensitivity is similar to purified protein derivative (PPD), rTPA38 demonstrates significantly higher specificity in diagnosing tuberculosis.
Area of Science:
- Immunology
- Microbiology
- Public Health
Background:
- Tuberculosis diagnosis faces challenges due to limitations of the current purified protein derivative (PPD) skin test.
- There is a need for more specific diagnostic tools to accurately identify tuberculosis infections.
Purpose of the Study:
- To evaluate recombinant truncated 38 kDa protein (rTPA38) of Mycobacterium tuberculosis as a potential new tuberculosis-specific tuberculin.
- To assess the sensitivity and specificity of rTPA38 compared to PPD in diagnosing tuberculosis.
Main Methods:
- Skin tests using the Mantoux technique were performed on 539 patients, 1133 healthy controls, and 55 guinea pigs.
- Sensitivity and specificity of rTPA38 were assessed against PPD.
- Cross-reactivity with M. bovis BCG vaccination was evaluated in healthy controls.
Main Results:
- rTPA38 showed comparable sensitivity to PPD (78.2% vs 83.4%).
- rTPA38 demonstrated significantly higher specificity than PPD (75.2% vs 47.0%).
- rTPA38 exhibited lower cross-reactivity with M. bovis BCG vaccination compared to PPD and showed specific reactions in M. tuberculosis-sensitized guinea pigs.
Conclusions:
- Recombinant truncated 38 kDa protein (rTPA38) shows potential as a specific antigen for tuberculosis skin testing.
- Its improved specificity over PPD could lead to more accurate tuberculosis diagnosis.
