Comprehensive Immunology Quiz — Killing OmpathStudy

Continued from $1. Immunology MCQs - Comprehensive Study Guide Chapter 21 - Killing in the Immune System Chapter: Immune Cell Functions and Mechanisms Question 1: Parasitic Worm Immunity Parasitic worm eggs are resistant to low pH and proteolytic digestion in the stomach. Adult worms living inside the lower gut are protected from many of the components of the immune response. Mast cells respond to worms. What immunoglobulin activates these mast cells, leading to degranulation? a) IgAb) IgDc) IgEd) IgGe) IgM Correct Answer: C) IgE Explanation: IgE is the primary immunoglobulin involved in allergic reactions and parasitic infections. It binds to high-affinity receptors (FcεRI) on mast cells and basophils. When parasitic antigens cross-link IgE molecules on these cells, it triggers degranulation, releasing histamine and other inflammatory mediators that help combat the parasitic infection. --- Questions 2.1-2.4: Mast Cell Mediators Question 2.1 Match the description with the pre-stored granular chemical mediator: Increases vascular permeability a) Trypase & Chemotrypsinb) Histaminec) Cytokines/IL-4d) Cytokines/TNF Correct Answer: B) Histamine Explanation: Histamine is the primary mediator responsible for increased vascular permeability. It causes vasodilation and increases the leakiness of blood vessels, allowing immune cells and proteins to enter tissues more easily. Question 2.2 Increase mucus secretion and smooth muscle contraction a) Trypase & Chemotrypsinb) Histaminec) Cytokines/IL-4d) Cytokines/TNF Correct Answer: A) Trypase & Chemotrypsin Explanation: These are proteolytic enzymes stored in mast cell granules. They contribute to tissue remodeling, mucus secretion, and smooth muscle contraction, particularly important in asthmatic responses. Question 2.3 Enhance diapedesis and stimulate TH2 responses a) Trypase & Chemotrypsinb) Histaminec) Cytokines/IL-4d) Cytokines/TNF Correct Answer: D) Cytokines/TNF Explanation: TNF-α (Tumor Necrosis Factor-alpha) enhances diapedesis (movement of immune cells through blood vessel walls) and helps coordinate inflammatory responses, including stimulating TH2 cell responses. Question 2.4 Activates TH2 and stimulates eosinophil production a) Trypase & Chemotrypsinb) Histaminec) Cytokines/IL-4d) Cytokines/TNF Correct Answer: C) Cytokines/IL-4 Explanation: IL-4 is a key cytokine that promotes TH2 differentiation and stimulates eosinophil production and activation. It's crucial in allergic responses and anti-parasitic immunity. --- Question 2.5: Arachidonic Acid Metabolites Mast cell arachidonic acid metabolites include cyclo-oxygenase, which produces prostaglandins that stimulate and increase of smooth muscle in the gut and bronchi. Metabolites also include leukotrienes, which have a effect than prostaglandins. a) Vasoconstriction; Constriction; Slowerb) Vasoconstriction; Constriction; Fasterc) Vasodilation; Dilation; Slowerd) Vasodilation; Dilation; Fastere) Vasodilation; Constriction; Slowerf) Vasodilation; Constriction; Faster Correct Answer: E) Vasodilation; Constriction; Slower Explanation: Prostaglandins cause vasodilation (increased blood flow) but also cause smooth muscle constriction in airways and gut. Leukotrienes have a slower onset but more prolonged effect compared to prostaglandins and are particularly important in asthma. --- Question 2.6: Initial Mast Cell Activation Which of the following would NOT act initially during mast cell (or basophil) activation? a) Trypaseb) Chemotrypsinc) Histamined) Prostaglandinse) Leukotrienes Correct Answer: E) Leukotrienes Explanation: Leukotrienes are newly synthesized mediators that require time for production from arachidonic acid metabolism. The other options are either pre-stored in granules (trypase, chemotrypsin, histamine) or rapidly produced (prostaglandins). --- Question 3: Eosinophils Which of the following is NOT true regarding eosinophils? a) They are specifically recruited to tissues during some types of inflammationb) Their granules contain particularly toxic substancesc) Their production is stimulated by IL-3 and IL-5d) They are recruited to parasite infected sites by chemokine eotaxine) They are a major acidic and anionic protein Correct Answer: E) They are a major acidic and anionic protein Explanation: Eosinophils CONTAIN major basic protein (which is cationic/basic, not acidic and anionic). This protein is toxic to parasites and is stored in their granules. All other statements are correct about eosinophils. --- Natural Killer (NK) Cells Questions 4.1-4.4: NK Cell Functions Question 4.1 Natural killer (NK) cells are excellent killers of cells infected by some . They also have an additional role of stimulating the immune response. a) Bacteria; Adaptiveb) Viruses; Adaptivec) Bacteria; Innated) Viruses; Innate Correct Answer: B) Viruses; Adaptive Explanation: NK cells primarily target virus-infected cells and tumor cells. They bridge innate and adaptive immunity by releasing cytokines that stimulate adaptive