10 Questions
What are the two recombinant proteins used to stimulate the release of interferon gamma in IGRA test systems?
ESAT6 and CFPT10
What is the primary limitation of IGRA test systems in population screening for tuberculosis?
High cost and requirement for specialized laboratory equipment and personnel
What type of blood cells are isolated and evaluated in the ELISPOT (T-SPOT.TB) system?
Peripheral blood mononuclear cells
How do the ELISA quantifier and QuantiFERON coat TB golden tube systems differ from the ELISPOT system?
They evaluate the concentration of interferon gamma in blood plasma, rather than visually counting stained zones
What is a significant challenge in using IGRA test systems in pediatric populations?
Required intravenous manipulation in children
What is the primary mechanism by which IGRA test systems detect Mycobacterium tuberculosis and Mycobacterium bovis?
activation of memory T-cells that release interferon-gamma in response to stimulation with recombinant proteins ESAT6 and CFPT10
What is the main purpose of incubating whole blood with recombinant proteins ESAT6 and CFPT10 in IGRA test systems?
to stimulate the release of interferon-gamma from activated memory T-cells
How do laboratory specialists evaluate the results of the ELISPOT (T-SPOT.TB) system?
by visually or digitally counting the number of spot-forming units, which represent individual T-cells that have released interferon-gamma
What is a major limitation of IGRA test systems in terms of their practical application?
they require specialized laboratory equipment and trained personnel, as well as strict conditions for blood sample preparation and storage
What is the primary reason why IGRA test systems are not suitable for population screening for tuberculosis?
they are expensive and require complex laboratory procedures, making them impractical for large-scale screening
Study Notes
Interferon-Gamma Release Assays (IGRA)
- International studies on the mycobacterium genome led to the development of two IGRA variants for TB diagnosis
- IGRA tests detect interferon-gamma release by activated memory T-cells in response to stimulation with recombinant proteins ESAT6 and CFP10
- Fresh blood is required for the analysis
ELISPOT (T-SPOT.TB) System
- Isolates peripheral blood mononuclear cells
- Evaluates the number of stain zones (visual or device-based)
- Sustains peripheral T-cells that release interferon-gamma after incubation with CFRT10 and ESAT6 recombinant proteins
ELISA QuantiFERON System
- Evaluates the concentration of interferon-gamma in blood plasma using enzyme-linked immunosorbent analysis
- Uses whole blood incubated with CFP10 and ESAT6 recombinant proteins
- QuantiFERON Coat TB Golden Tube is used for analysis
Limitations of IGRA Tests
- High cost
- Requires equipped laboratory and specialists
- Strict requirements for biological material preparation, storage, and blood processing
- Intravenous manipulation required in children
- Further studies needed to define their relevance in TB diagnostics
Interferon-Gamma Release Assays (IGRA)
- International studies on the mycobacterium genome led to the development of two IGRA variants for TB diagnosis
- IGRA tests detect interferon-gamma release by activated memory T-cells in response to stimulation with recombinant proteins ESAT6 and CFP10
- Fresh blood is required for the analysis
ELISPOT (T-SPOT.TB) System
- Isolates peripheral blood mononuclear cells
- Evaluates the number of stain zones (visual or device-based)
- Sustains peripheral T-cells that release interferon-gamma after incubation with CFRT10 and ESAT6 recombinant proteins
ELISA QuantiFERON System
- Evaluates the concentration of interferon-gamma in blood plasma using enzyme-linked immunosorbent analysis
- Uses whole blood incubated with CFP10 and ESAT6 recombinant proteins
- QuantiFERON Coat TB Golden Tube is used for analysis
Limitations of IGRA Tests
- High cost
- Requires equipped laboratory and specialists
- Strict requirements for biological material preparation, storage, and blood processing
- Intravenous manipulation required in children
- Further studies needed to define their relevance in TB diagnostics
Learn about the development and methodology of Interferon-Gamma Release Assays (IGRA) and the ELISPOT (T-SPOT.TB) System for diagnosing tuberculosis.
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