Exam 4: Ch 19 Flashcards
innate versus adaptive immunity
innate is found in all multicellular organisms. first line of defense. usually recognizes host versus foreign cells but it can’t identify the foreign cells.
Adaptive can identify foreign cells. found in all vertebrates. can retain memory of pathogens and deploy specific defenses against a pathogen.
siderophores
a molecule that binds and transports iron in microorganisms. produced by host cells and pathogens. war for iron.
proinflammatory molecule
Any molecule produced by cells, such as certain cytokines, which induces or stimulates the inflammatory response; examples include IL-1, IL-12, TNF-α, and IFN-γ
cytokines
Any member of a group of secreted, soluble, low molecular weight glycoproteins used as the primary means of cell-to-cell communication to regulate inflammatory and immune responses; includes interleukins, interferons, and tumor-necrosis factors.
Release of cytokines, primarily by leukocytes, is the primary mode of communication used to signal information regarding an infection.
Cytokines can produce fever, enhance inflammation, and stimulate further immune responses.
pathogen-associated molecular pattern (PAMP)
Broad-based molecular signature or motif commonly associated with pathogens but not normally found in the host
pattern recognition receptor (PRR)
Receptor of the innate immune system capable of recognizing pathogen-associated molecular patterns (PAMPs)
Toll-like Receptors (TLR)
Membrane-associated pattern recognition receptor (PRR) of the innate immune system that recognizes a panel of pathogen-associated molecular patterns (PAMPs) and can induce expression of various cytokines and other products
opsonization
Coating of a microbial surface with host components, such as complement or antibody, to aid in phagocytosis
complement
Group of serum proteins of the innate immune system that can become activated to undergo a cascade of cleavage reactions in the presence of extracellular pathogens; end result of complement activation is formation of the membrane-attack complex (MAC) and generation of complement factors with supplementary immune functions
Membrane attack Complex (MAC)
Pore-forming structure resulting from complement activation, composed of complement factors C5b, C6, C7, C8, and polymerized C9 that forms in microbial membranes to cause lysis
antibody
Secreted immunoglobulin produced by B cells, specifically plasma cells, of the adaptive immune system
lectin pathway
Complement cascade activation pathway initiated by the complexing of mannose-binding lectin with other serum proteins to produce C1-like activity, which activates the complement cascade
alternative pathway
Complement cascade activation pathway initiated by the binding of an alternative form of C3b to a variety of cell wall components
classical pathway
Complement cascade activation pathway initiated by C1 binding directly to certain surface components of pathogens, for example, LPS and lipoteichoic acid, or binding to surfaces coated with C-reactive protein or antibody; utilizes complement components C1 through C9
Type I Interferons (IFN)
Includes the cytokines interferon-α and -β produced by many cell types upon viral infection to induce an antiviral state in infected and uninfected neighboring cells
endocytosis
Generalized process for the uptake of external materials by cell membrane extension or invagination and fusion to form a vesicle inside the cytoplasm of the cell generally known as an endosome
cytotoxic cell
Any effector cell of the immune system containing cytotoxic granules, which when released induce apoptosis of target cells; natural killer (NK) cells, mast cells, and cytotoxic CD8+ T (TC) cells are examples
Opsonins
Any component of the immune system capable of binding and coating a microbial surface to enhance its phagocytic uptake; examples include antibody, C3b, C-reactive protein, and mannose-binding lectin
endosome
General term for a membrane-bound vesicle produced by endocytosis
phagosome
Membrane-bound vesicle produced through phagocytosis and containing engulfed particles
phagocyte
- Leukocyte, such as a macrophage or neutrophils, capable of engulfing particulate matter, such as bacterial cells
- facilitated by opsonization
- uses a type of endocytosis
- Phagocytosis forms an endosome called the phagosome that enters the degradative endocytic pathway
endocytic pathway
The flow of material internalized by endocytosis and degraded through a number of biochemical processes until its expulsion from the cell; involves a series of vesicle fusion events; only in eukaryal cells
respiratory (oxidative) burst
Generation of highly toxic oxygen compounds, such as nitric oxide and hydrogen peroxide, inside the phagolysosome to kill phagocytosed microbes
Natural Killer (NK) cells
Cytotoxic lymphocyte of the innate immune system that recognizes infected and abnormal cells and kills them by releasing toxic granular contents, causing apoptosis of the target cell,
NK cells possess granules containing perforin and granzymes.
perforin - hole punch in membrane
granzymes - apoptosis
class I major histocompatibility complex (MHC I) molecule
Cell surface molecule expressed by many cell types that presents endogenous antigen to CD8+ T cells
hemocyte
Wandering phagocytic cell of invertebrates that migrates from hemolymph (blood) into tissue
Amoebocyte
Invertebrate cell derived from an activated hemocyte, containing antimicrobial peptides and clotting factors to fight infection and reduce tissue damage
Steps of the inflammation process and phagocytosis
inflammation steps:
(1) vasodilation - An increase of the diameter of the blood vessel, such as during inflammation
(2) increased vessel permeability
(3) extravasation - Movement of cells and fluid from a blood vessel into the surrounding tissue
- immune cells (phagocytes) are brought in during these steps
- Active phagocytes release chemoattractants, such as interleukin 8 (IL-8), that attract more cells with immune function to the area.
- phagocytes engulf debris and foreign microbes
How the skins serves as a barrier to protect against pathogens?
cool, dry, and acidic (pH 5). the layer of dead skin cells. antimicrobial serum and sweat. natural microbiota of yeast that competes for resources.
What does complement do and what is the final product and outcome?
Complement components exist as inactive precursor proteins in the blood. Enzymatic cleavage and conformational changes of the precursors occur through a cascade, whereby one activated complement factor acts on another precursor in a sequential manner. An end result of the complement cascade is the formation of the pore-forming membrane attack complex (MAC), which leads to microbial death by lysis
What is opsonization and what role does it play in innate and adaptive immunity?
opsonization occurs when the immune system recognizes a pathogen-associated molecular pattern (PAMP) and Mannose-binding lectin (MBL) coats it which in turn activates complement and aids in phagocytosis.
mucosal membranes
interior surfaces coated with wet mucus
* Moved along the surface to prevent microbe attachment
* Contain ANTIMICROBIAL molecules:
* Defensin proteins
* Lysozyme
* Lactoferrin
* Competitive exclusion by normal flora (again!)
antimicrobial peptides
A member of a group of low molecular weight proteins secreted by various cell types in plants, invertebrates, and vertebrates that appear to destabilize the membrane structure of microbes, resulting in disruptive gaps or pores. DEFENSINs are an example.
A common defense in mucosal surfaces
lactoferrin
Small iron-transporting protein found in body secretions such as milk, tears, and saliva and found intracellularly in the granules of phagocytes
mannose-binding lectin (MBL)
Serum pattern recognition receptor (PRR) of the innate immune system that binds mannose polymers of yeast and bacterial cell walls
MHC I binds with ___
MHC II binds with ___
CD8
CD4
both equal 8
