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Serodiagnosis of tuberculosis using purified mycobacterial proteins
N K Kaushik1, G V Choudary, P Sharma
1V.P. Chest Institute, Delhi.
Abstract:
With a view to detect specific M. tuberculosis infection, mycobacterial proteins were purified initially by ammonium sulphate precipitation followed by ion-exchange chromatography. Out of the three fractions, namely P1, P2 and P3 precipitated with increasing concentrations (0-25%, 26-65% and 66-100% respectively) of ammonium sulphate, P2 fraction was found to be more immunoreactive. P2 fraction proteins were further fractionated into five fractions by salt gradient using DEAE-cellulose DE-52 ion-exchange chromatography. Immunoreactivity against tuberculous patients sera of all the fractions was assessed using ELISA test. The last fraction (DE-V) eluted with high salt concentration was found to have a more specific immunoreactive set of proteins within the range of 55 kD to 67 kD molecular weight. Multiple non-specific proteins were distributed in all the other fractions. ELISA test using P2 fraction proteins against tuberculous patients sera showed significantly higher (p less than 0.01) titre even in the absence of any other bacteriological evidence. DE-V fraction of P2 proteins was found to have a significantly high specificity for detecting M. tuberculosis infection in clinically confirmed and suspected tuberculous patients indicating its application in the diagnosis of the disease.
Insights
Researchers identified specific Mycobacterium tuberculosis proteins for accurate infection detection. The DE-V fraction shows high specificity in diagnosing tuberculosis (TB) in patients, even with unclear bacteriological evidence.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Accurate diagnosis of Mycobacterium tuberculosis infection is crucial for effective treatment and control.
- Current diagnostic methods may lack specificity or require extensive bacteriological evidence.
Purpose of the Study:
- To purify and identify specific mycobacterial proteins for detecting Mycobacterium tuberculosis infection.
- To evaluate the diagnostic potential of purified protein fractions in tuberculous patients.
Main Methods:
- Mycobacterial proteins were purified using ammonium sulfate precipitation and DEAE-cellulose ion-exchange chromatography.
- Fractions were screened for immunoreactivity against sera from tuberculous patients using ELISA.
- Protein specificity and molecular weight were analyzed.
Main Results:
- The P2 fraction showed higher immunoreactivity, with the DE-V sub-fraction exhibiting specific reactivity.
- The DE-V fraction contained proteins in the 55-67 kD range and demonstrated high specificity for M. tuberculosis.
- ELISA using P2 fraction showed significantly higher titers in tuberculous patients.
Conclusions:
- The DE-V fraction of P2 proteins possesses high specificity for detecting M. tuberculosis infection.
- This fraction holds significant potential for application in the diagnosis of tuberculosis.