Immune System Activation Mechanisms Quiz

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What is the most likely consequence of C5a activation on mast cells in the context of an allergic reaction?

Decreased cytokine release

Increased itching (correct)

Decreased histamine release

Increased inflammation

In delayed-type hypersensitivity, what is the role of T regulatory (Treg) cells as hapten levels drop?

Activating mast cells

Inducing vasodilation

Promoting wound healing (correct)

Enhancing inflammation

What type of immune response is predominantly generated in granulomatous hypersensitivity?

CD8+ cell response

Th2 cell response

CD4+ Th1 cell response (correct)

Macrophage-mediated response

What happens to airway macrophages upon uptake of bacteria in chronic infections?

Penetration into underlying tissues Signup and view all the answers

Which of the following does NOT contribute to the pathophysiology of granulomatous hypersensitivity?

Treg cell activation Signup and view all the answers

How do reactive oxygen and nitrogen species (ROS, RNS) contribute to skin redness, inflammation, and blistering?

By degrading DNA Signup and view all the answers

Which of the following best describes the process that allows a quarantined microbe to escape the fibrous capsule within a granuloma?

The microbe gains access to the airway by lysis of infected macrophages. Signup and view all the answers

In Type IV hypersensitivity reactions, what is the role of dendritic cells (DC) in the immune response?

DC present self-antigens to CD4+ and CD8+ T cells. Signup and view all the answers

What contributes to the recruitment of neutrophils and monocytes into the tissue during a Type IV hypersensitivity reaction?

Local inflammation triggered by macrophage and mast cell activation Signup and view all the answers

How do self-reactive T cells persist in lymph nodes and spleen in Type IV hypersensitivity reactions?

By escaping tolerance mechanisms in the thymus Signup and view all the answers

What causes infected macrophages within a granuloma to release viable bacteria into the tissue and airway?

Escape of bacteria through lysis of infected macrophages Signup and view all the answers

What is one of the main consequences of foamy cells becoming more susceptible to infection by a pathogen?

Decrease in lipid levels within foamy cells Signup and view all the answers

Which process leads to the release of mediators into the environment such as prostaglandins and chemokines?

Frustrated phagocytosis Signup and view all the answers

What can lead to the formation of microthrombi in blood vessels by inducing platelet aggregation?

Platelet activating factor (PAF) Signup and view all the answers

What is a key process that can contribute to tissue necrosis due to prolonged activation of phagocytes?

IC formation Signup and view all the answers

In the context provided, what is a characteristic feature of Rheumatoid Arthritis (RA)?

Presence of high levels of Rheumatoid Factor (RF) Signup and view all the answers

Which statement is true regarding the susceptibility factors for Systemic Lupus Erythematosus (SLE)?

HLA-DR4 confers the greatest susceptibility to SLE. Signup and view all the answers

Which process contributes to the chronic disease setting often resulting in death in SLE patients?

Epitope spreading Signup and view all the answers

In Type IV hypersensitivity reactions, what is a key characteristic of the effector stage of contact hypersensitivity?

Participation of CD8+ T cells in tissue inflammation through various mechanisms Signup and view all the answers