Microbio quiz 4

ability to resist infection

immunity

the non-inducible (”hard-wired”, inborn) ability torecognize and destroy an individual pathogen or its products

innate immunity

example of innate immunity

lysozyme

The acquired ability to recognize and destroy a particular pathogen or its products. Dependent on previous exposure (specificity). Directed toward an individual molecular component of the pathogen (antigen)

adaptive immunity

primary effector cells of innate immunity

phagocytes

primary effector cells of adaptive immunity

lymphocytes

general response to innate immunity

dendritic cell, neutrophil, macrophage

focused attack (cells) for adaptive immunity

B and T lymphocytes,

(barriers to pathogen invasion). ________ ______ is on skin and gut. Competitive exclusion

normal microbiota

(barriers to pathogen invasion). very young, very old, malnourished,

stressed, smoking, IV drugs, alcohol, sleep deprived

host condition

(barriers to pathogen invasion). Ability of ________ to cause ______. Varies between species

microbes, disease.

Natural host resistance (3)

normal microbiota, host condition, ability of microbes to cause disease

Physical and chemical barriers to infection

mucosal membranes, stomach acid, skin

Which immunity is the first line of defense and present before birth

innate immunity

Which immunity is specific to the target and slower to activate

adaptive immunity

white blood cells of innate immunity

polymorphonuclear leukocytes, monocytes, macrophages, dendritic cells, mast cells

Makes up nearly all WBCs in blood, rapid responders, can engulf microbes by phagocytosis

neutrophils

Phagocytose less efficiently than neutrophils, release products that are toxic to microbe, participate in allergic and inflammatory reactions. (2)

basophils and eosinophils

Contain many granules rich in histamine (vasodilator & inflammatory and allergic response chemical) and heparin (anticoagulant). Help with inflammation and wound healing. Unlike PMNs, reside in connective tissues and mucosa and do not circulate in the bloodstream

mast cells

Circulate in the blood, Engulf foreign materials. Differentiate into macrophages and dendritic cells

monocytes

Widely distributed throughout the body. Phagocytose. “Present” antigens on cell surface to T cells

macrophages

Located in the spleen and lymph nodes and Langerhans cells in skin. Phagocytose. “Present” small antigens on their cell surface to T cells. Different from macrophages in structure

dendritic cells

granulopoiesis (polymorphonuclear leukocytes)

basophils, neutrophils, eosinophils

Antibodies and complement proteins bind to pathogens, marking them for phagocytosis. Phagocytes recognize these proteins through Fc receptors and complement receptors.

opsonization

__________ _________ _________ (PRRs) recognize _________ -_______ ________ ________

pattern recognition receptors, pathogen-associated molecular patterns

Healthy cells express _______ a “_______ _____ ____” signal that inhibits phagocytosis

CD47, don’t eat me

Dying or damaged cells expose phosphatidylserine, an “____ ___” signal that promotes phagocytosis.

eat me

Most bacteria are __________ _____ — they live outside host cells

extracellular pathogens

The immune system for bacterial infections relies mainly on _______ immunity (phagocytosis)

innate

viral infections rely more on ______ immunity

adaptive

Viruses are ____________ _____ — they replicate inside host cells

intracellular pathogens

destroys virus-infected cells

cytotoxic T cells (CD8)

activates cytotoxic T cells and B cells

helper T cells (CD4)

__ _____ produce antibodies that neutralize free viral particles

B cells

A localized response to tissue injury or infection that helps contain and eliminate pathogens

inflammation

Bring immune cells and molecules to the infection site, promote healing and prevent spread of infection

purpose of inflammation

Inflammation is __________ by Pathogen-associated molecular patterns (PAMPs) recognized by immune cells, Cytokine release (e.g., IL-1, TNF-α, IL-6)

triggered

Key Signs (5 cardinal signs)

redness, heat, swelling, pain, loss of function

main immune cells involved in inflammation

mast cells, neutrophils, macrophages

Signal leading to inflammation: _________; microorganisms grow, produce cell damaging compounds

infection

Signals leading to inflammation: _________; phagocytosis, release of inflammatory mediators, release cytokines to communicate with other cells

macrophages

Increase vascular permeability by loosening tight junctions between

epithelial cells → initiates dialation

vasoactive factors

signs leading to inflammation: _______ _____; histamine

Mast cells

The movement of neutrophils through capillary vascular walls is called _________.

extravasation

__________ slows blood flow and as a result, increases blood volume in the affected area

vasodilation

The more _______ vessel allows the escape of plasma into the tissues

permeable

Vasodilation and extravasation cause localized __________, _______, and _______.

swelling, redness, heat

vasoactive factors also stimulate local nerve endings, causing _______.

pain

results from the persistent presence of a foreign body; permanent tissue damage

chronic inflammation

infection, granuloma, irritant material, wood splinters, asbestos particles, and surgical implants are all ________ of chronic inflammation

causes

structured collection of immune cells that walls off a persistent pathogen the body cannot eliminate, body’s attempt to “wall off” infection/irritant

granuloma

systemic rise in body temperature triggered by infection

fever

A fever is triggered by ________.

pyrogens

(from the host), triggers fever and acts on the hypothalamus, raising the body’s temperature set point

endogenous pyrogens

(from microbes): lipopolysaccharide (LIPS), triggers fever and acts on the hypothalamus, raising the body’s temperature set point

exogenous pyrogens

•Inhibits growth of many microbes (they prefer normal body temp).

•Speeds up immune reactions (increased phagocytosis and T-cell activity).

•Reduces iron availability to pathogens (since bacteria need iron).

functions of fever

A whole-body defense mechanism that enhances immune efficiency.

outcome of fever

Genetic disease where the patient forms no T-cell lymphocytes and has dysfunctional (or sometimes no) B-cell lymphocytes

severe combined immunodeficiency (SCID)

Severe SCID patients can/cannot launch a meaningful adaptive immune defense against any invading microbe—whether it be pathogen or normal microbiota

cannot

________ immunity develops after exposure to an antigen

adaptive

– Complex and slow development

– Cross-regulated defense network

– Memory response

key properties of adaptive immunity

_________: Anything that can elicit an immune response. If it itself can elicit an immune response, it is termed to be an __________

antigen, immunogen

specific binding site on antigen, can have more than one

epitope

Immune cells have surface receptors that interact with individual antigens

specificity

from birth, the ______ immune system is capable of recognizing and responding to billions of possible foreign (but not self) antigens

naive

We have extremely ______ antigen specific receptors to respond to variety of antigens

diverse

Two forms of adaptive immunity

Humoral (B-cells and Plasma cells), Cell-mediated

Adaptive immunity (Humoral): proteins that circulate in the bloodstream and recognize foreign structures called antigens

antibodies

Adaptive immunity (Humoral): B cells that have been stimulated by antigen to produce antibodies

Plasma cells

Adaptive immunity: T cells recognize antigen, can stimulate B cells, destroy infected host cells

cell-mediated

Antigen reactive leukocytes

lymphocytes

Produce antibodies against extracellular antigens, antibody-mediated immunity

B cells

Produce antigen-specific receptor proteins on their surfaces against intracellular antigens, cell-mediated immunity

T cells

The adaptive immune response _____ when cells of the innate immune response engulf a microbe and break it down into component antigens

begins

Phagocytic cells involved may be called ________ ________ _____.

Antigen presenting cells (APCs)

Types of cells that are antigen presenting cells (APCs)

dendritic cells and macrophages

APCs place antigen and epitopes on their cell surface (______ _________ _______ (MHC) proteins) in order to “present” the to T lymphcytes

major histocompatibility complex

The “display” of antigens on MCH happens some/none/all of the time in the background even in uninfected cells

all

Antigen-binding sites, highly variable amino acid sequences, antigen-binding site different. (binds peptidoglycan only vs. another antigen)

F(ab)2 region

F(ab)2 region has two variable regions:

VL, VH

F(ab)2 region binding is irreversible/reversible. The bonds are ______

reversible, noncovalent

binds receptors on host cells

Fc region

IgA forms a _____ while igM forms a ________

dimer, pentamer

An antigen binds to B-cell receptor (specific to that particular antigen), B cell is activated, Begins to proliferate and differentiate into a plasma cell. (antibody secreting cell, memory cells)

Primary antibody response

Basis of immunization, after B-cell activation (memory cells are generated), when memory B cells encounter antigen again they quickly trigger a robust secondary antibody response

secondary antibody response

________ __ _____ (TC cells) bind antigen presented on antigen presenting cells

Cytotoxic T cells

Upon activation, the cytotoxic T cells leave the _____ ____ and find host cells presenting the same antigen

lymph node

cytotoxic T cells ____ the infected host cell

kill

_________ __ ______ (TH cells) link the two forms of adaptive immunity

Helper T cells

TH cells determine whether ________ or ____-________ mechanisms will predominate in response to an antigen

antibody, cell-mediated

T-cell activation requires ________-_________ ______ and ________ ____________ _________ proteins present antigens

antigen-presenting cells (APCs), Major histocompatibility complex

Class __ MHC molecules are found on all nucleated cells (not red blood cells)

I

Class __ MHC molecules are found only on dendritic cells, macrophages, and B cells

II

MHC Class __ presentation: Extracellular pathogens - Pathogens are phagocytosed. Digestion

II

MHC class __ presentation: Intraceulluar pathogens. Grow on the cytoplasm of the cell, degrade

I

__________ cells can present viral/intracellular antigens via MHC I presentation that can be recognized by activated T cells

infected

The T-cell receptor (TCR) binds antigen on the ________ of __ cells

surface, T

TCR binds peptides within ___ _______

MHC molecules

TCR is associated with the ____ (cell signaling) complex

CD3

When TRC binds to MHC-antigen complex, CD3 signals ________ of T cells. _______ selected to multiple

proliferation, clonally