203 Immunology Tutorial 2: The Immunology of Infection

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What does the large amount of interferon-γ production after stimulation with TB antigens indicate?

The patient is immune to TB due to BCG vaccination

The patient has an active TB infection

The patient has circulating effector memory Th1 cells specific for TB antigens (correct)

The patient is at high risk of developing a latent TB infection

What is the purpose of incubating the patient's blood in tubes with the TB antigens CFP10 and ESAT-6 for 16 hours?

To induce necrosis in the blood sample for detection

To separate the antigens from the blood sample for ELISA analysis

To stimulate the production of Interferon-γ in the blood sample (correct)

To assess the fluid content of the blood sample

What is the significance of the IFN production in the negative control and PHA wells?

It confirms that the test is technically valid (correct)

It suggests a potential false positive result

It provides evidence of both vaccine-induced and exposure-induced immunity

It indicates an active TB infection

Why is the supernatant removed from the tube after incubating the blood with TB antigens?

To isolate the cells at the bottom of the tube for further analysis Signup and view all the answers

Why is it important to understand that the antigens used in the QFT Gold test are not contained in the BCG vaccine?

To differentiate between vaccine-induced and exposure-induced immunity Signup and view all the answers

What is the purpose of analyzing the supernatant for IFN-γ using ELISA?

To detect the presence and quantity of Interferon-γ in the blood sample Signup and view all the answers

Why is the QFT Gold test not a good test for active TB?

It doesn't measure interferon-γ production after stimulation with TB antigens Signup and view all the answers

Based on the given information, what might be offered to a patient with a positive Interferon-γ release assay?

Treatment for active tuberculosis infection Signup and view all the answers

What treatment may be warranted for a patient who has produced large amounts of interferon-γ after stimulation with TB antigens?

Chemoprophylaxis to reduce the risk of progression to active TB Signup and view all the answers

What would be an appropriate interpretation of a positive result in an Interferon-γ release assay?

The patient has active tuberculosis infection requiring immediate treatment Signup and view all the answers

What is the main purpose of the acidic environment, activation of digestive enzymes, and oxidative burst in the context of TB infection?

To destroy the TB organism Signup and view all the answers

Why are some MTB organisms difficult to eliminate within macrophage phagolysosomes?

They inhibit phagosome maturation and phagosome/lysosome fusion Signup and view all the answers

How are CD4 T helper cells activated during TB infection?

By MTB antigens inducing the macrophage to secrete IL-12, leading to a strong Th1 response Signup and view all the answers

What immunological process results in the formation of a Ghon focus in TB infection?

Containment of primary MTB infection by the immune system Signup and view all the answers

What role does lFN-γ play in the context of TB infection?

Promoting phagosome maturation and phagosome/lysosome fusion to eliminate MTB organisms Signup and view all the answers

What is the primary function of Interferon-γ release assay (IGRA)?

To detect latent TB infection Signup and view all the answers

In the context of TB infection, what type of immune response does Interferon-γ release assay (IGRA) measure?

Cell-mediated immune response Signup and view all the answers

Which cells are involved in producing Interferon-γ in response to Mycobacterium tuberculosis antigens?

Helper T lymphocytes Signup and view all the answers

How does Interferon-γ contribute to the immune response against Mycobacterium tuberculosis?

By enhancing the killing ability of macrophages Signup and view all the answers

Which immunological technique is based on the principle of detecting Interferon-γ release from T cells exposed to Mycobacterium tuberculosis antigens?

ELISPOT assay Signup and view all the answers