35 Questions
Which of the following is NOT a major event in the inflammatory response?
Antibody production
What is the primary mediator of the inflammatory response among the following options?
Histamine
Which type of molecules influence host signaling pathways according to the text?
Bacterial metabolites
What is the main action of lysozyme in bacterial cells?
Cleaving peptidoglycan layer
Which of the following is a physiological barrier that contributes to innate immunity?
Temperature
The alternative pathway in the complement system is activated spontaneously by what mechanism?
Cleavage of C3
Which type of white blood cell is known to release histamine as a mediator of inflammation?
Basophil
Which toll-like receptor (TLR) recognizes peptidoglycan, a component of bacterial cell walls?
TLR2
What type of molecules are DAMPs (Damage Associated Molecular Patterns) associated with?
Host cell components due to damage or death
Which white blood cell is primarily responsible for the phagocytosis of pathogens?
Neutrophil
What is the primary role of Toll-Like Receptors (TLRs) in the immune system?
Identify pathogen-associated molecular patterns (PAMPs)
Which cells are part of the skin microbiota, contributing to the skin's defense mechanism?
Mast cells
Which of the following statements best describes the role of histamine as a mediator in the immune response?
Histamine is released during allergic reactions and contributes to vasodilation and increased vascular permeability.
How do bacterial metabolites contribute to the immune system's response to infections?
Bacterial metabolites act as signaling molecules, triggering inflammatory responses in the host.
In the context of the immune system, what is a key function of physiological barriers like the skin microbiota?
Skin microbiota produce antimicrobial peptides that help defend against invading pathogens.
Which of the following best describes the primary function of inflammatory responses in the immune system?
Inflammatory responses promote vasodilation and increased blood flow to areas of infection or injury.
Which statement accurately reflects a characteristic of physiological barriers in host defense mechanisms?
Physiological barriers like mucosal surfaces serve as a physical and chemical defense against pathogens.
How do physiological barriers such as skin contribute to preventing infections?
Skin provides a physical barrier that prevents pathogens from entering the body.
Which cell type is responsible for cell mediated immunity?
T Cells
Which cytokine is a proinflammatory cytokine produced in response to infection and inflammation?
TNF-α
Which of the following is NOT one of the characteristics of the Adaptive Immunity System?
Inflammatory regulation
What is the role of B cells in the immune response?
Produce antibodies
Which receptor do T cells express on their surfaces for antigen recognition?
TCR
What is the main function of TNF-α in the body?
Regulate inflammatory response
What are the 3 different ways phagocytes can attack microorganisms?
Phagocytosis, degranulation, and generation of neutrophil extracellular traps
Which cells are considered phagocytes according to the text?
Neutrophils and macrophages
What is the main action of interferon-gamma (IFN-γ) according to the text?
Activates macrophages and induces Class II MHC expression
Which compound found in phagocytes is responsible for degrading bacteria within phagosomes?
Peroxidase
In the process of phagocytosis, what fuses with the phagosome to produce a phagolysosome?
Lysosome
Which category of small proteins plays a crucial role in cell signaling and immunomodulation?
"Cytokines"
What is the primary function of Natural Killer (NK) cells in the immune system?
Identify and eliminate infected cells or tumor cells
How do Eosinophils contribute to the immune response according to the text?
They are involved in combating parasitic infections
What is the key function of Mast cells in the immune system?
Releasing histamine as a mediator of inflammation
What is the main role of Neutrophils among the white blood cells mentioned?
Identify and eliminate pathogens
Which class of white blood cells do Granulocytes belong to?
Granulocytes belong to the category of white blood cells
Study Notes
White Blood Cells
- Mast cells are a type of granulocyte that resides in tissue, containing granules with histamine and heparin, making them the most inflammatory cell in the body.
- Basophils are the blood equivalent of mast cells.
- Activated mast cells degranulate and release inflammatory mediators, making them a major target for anti-inflammatory drugs.
Eosinophils
- Eosinophils are designed to combat multicellular parasites and certain infections, and also play a role in allergy and asthma.
- They reside in blood, accounting for about 1-3% of WBCs, and are not overly phagocytic.
- Eosinophils function by releasing basic and cationic proteins, such as superoxide, peroxide, and hypobromite.
NK Cells
- Natural Killer (NK) cells are a type of cytotoxic lymphocyte, similar in function to T cells, that can recognize stressed cells in the absence of MHC.
- NK cells react quickly and play an important role in anti-viral and anti-tumour defences.
- They function by binding to cells and releasing cytotoxic granules.
Neutrophils
- Neutrophils are a type of phagocytic granulocyte, the most abundant WBC (60-70%) in most mammals.
- They are short-lived, highly mobile, and can get to places that other cells can't reach.
- Neutrophils are among the first responders to inflammation, attracted by cytokines, and are the predominant cells in pus.
- They can directly attack microorganisms in three ways: phagocytosis, degranulation, and generation of neutrophil extracellular traps (NETs).
Phagocytes and Phagocytosis
- Phagocytes are cells that specialize in "eating" cells, consisting of two types: neutrophils and macrophages.
- They contain granules with "killing" compounds, such as peroxidase, acid and alkali phosphatases.
- The phagocytic process involves: pseudopodia attaching to bacteria, bacteria ingested into phagosome, lysosome fusing with phagosome to produce phagolysosome, lysosomal enzymes degrading bacteria, and degraded material released from cell.
Cytokines
- Cytokines are a broad and loose category of small proteins (~5–20 kDa) that are important in cell signalling and immunomodulating on a local or systemic scale.
- They can be produced by multiple classes of cells, mainly helper T cells and macrophages.
- Different subclasses of cytokines have specific actions, and the general action of cytokines involves stimulus, stimulated cell producing cytokine, cytokine secretion, activation of cytokine-specific receptor on target cell, cell activation, and biological effect.
- Interferons (IFN) are antiviral proteins, with IFN-γ specifically activating macrophages and inducing Class II MHC.
Test your knowledge on innate immune receptors such as TLRs, CLRs, and NLRs, which play a crucial role in recognizing pathogen associated molecular patterns (PAMPs) and damage associated molecular patterns (DAMPs). Learn about specific examples like LPS recognized by TLR4 and the activation of TLR3 by damaged RNA.
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