All of the following are characteristic of mannose-binding lectin except Select one: a. acts as an opsonin by binding to mannose-containing carbohydrates of pathogens b. synthesized by hepatocytes C. induced by elevated IL-6 levels d. a member of the collectin family triggers the alternative pathway of complement activation. e.

The formation of the C3 convertase is a key step in complement activation that occurs in all three complement pathways. This enzyme cleaves C3 in blood plasma, leading to a conformational change in the C3b fragment that exposes its reactive thioester group. The activated C3b is potentially harmful to the host, if it becomes covalently attached to a host cell, rather than to the surface of a pathogen. This deleterious outcome is largely avoided by:  The inability of active C3b to diffuse away in the blood plasma. The inability of active C3b to covalently attach to the membranes of eukaryotic cells. The rapid hydrolysis of active C3b in solution, rendering it inactive. The tight binding of active C3b to the C3 convertase. The ability of active C3b to recruit phagocytic cells.

Individuals infected with herpes simplex virus (HSV) mount protective antibody responses directed against surface glycoproteins of the virus.   These antibodies are critical to viral clearance.  The act to neutralise any virus trying to infect a person’s cells as well as activating the classical pathway of complement and cytotoxic cell-mediated killing of infected target cells. Having a deficiency in the complement component C3 greatly impairs a person’s ability to control HSV infections.   To understand this further, you will investigate this in the lab.  Using C3-deficient mice, you infect them with HSV at day 0 and then a second time 4 weeks later.           A hypothesis is a tentative answer to a scientific question and is an important part of practical experiments.  A testable hypothesis is statement that can be proved or disproved as a result of experimentation.   Q1. State the problem that you are trying to solve. And then formulate a robust testable hypothesis for your…

T cells in the thymus are determined to be T helper cells or T killer cells while undergoing maturation in the Choose from the folloiwng: (A) cortex of the thymus (B) medulla of the thymus

Based on the figure presented in attachment what is the most likely ligand for TLR-XX? Be as specific as possible, and justify your answer based on these data only. Thanks

Which of the following is not a function of antibodies? Select one: a. They neutralize pathogens by masking the pathogen surface. b. They act as molecular adaptors that bridge together pathogen and phagocyte surfaces. c. They exert toxic effects directly. d. They act as opsonins that mediate phagocytosis. e. They activate complement fixation.

Complexes of IgG bound to soluble multivalent antigens can activate the classical pathway on the complex, targeting it for of complement, resulting in the deposition of endocytic uptake by cells bearing. Select one: a. C4b; CR2 and Fc receptors b. c. C5-9; CR1 and Fc receptors d. C3b; CR1 and Fc receptors e. C2a; CR2 and Toll-like receptors C3b; CR2 and Toll-like receptors

A patient develops a blood infection with a capsule-producing strain of E. coli. Phagocytosis by macrophage will be essential to destroy the bacteria and resolve the infection. Which of the following will be dirertly required to allow ADCC-opsonization of the encapsulated E. coli: O Toll-like receptor (TLR)-induced secretion of tumor necrosis factor alpha O Release of C3a to the extracellular fluids O Presence of MHC II on the surface of the macrophage O Presence of IgG receptors (Fc-gamma-R) on the macrophage All of the answers apply

Which of the following does not accurately describe complement components?   A. made by the spleen   B. located in extracellular spaces   C. some function as proteases once activated   D. activated by a cascade of enzymatic reactions.   E. soluble proteins

The zone of contact between the T cell and a pathogen-infected cell is called a(n) Select one: a. immunoreceptor tyrosine-based activation motif (ITAM) b. polarization C. cross-presentation center d. granuloma e. immunological synapse