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Bio 240 Immunity CH

Terms in this set (96)

agents that cause disease, infect a wide range of animals, including humans; the host offers some sort of benefit to the pathogen

In _________, an exoskeleton made of chitin forms the first barrier to pathogens

an enzyme that breaks down bacterial cell walls and acts as a chemical barrier against pathogens ingested with food

In insects Hemocytes circulate within hemolymph and carry out ________________, the ingestion and digestion of foreign substances including bacteria; can also release antimicrobial peptides to kill fungi or bacteria

_______ ________include the skin and mucous membranes of the respiratory, urinary, and reproductive tracts; block the entry of pathogens;

barrier defenses

a viscous fluid that traps pathogens, inhibit colonization of fungi and bacteria.

The low __ of skin and the digestive system prevents growth of many bacteria & stomach acid kills many bacteria before they enter the intestines

______ ______ cells in mammals detect, devour, and destroy invading pathogens

These cells recognize groups of pathogens using TLRs, or ____-____ receptors
TLRs recognize fragments of molecules characteristic of a set of pathogens

There are two main types of phagocytic cells, which engulf and destroy pathogens, in the mammalian body

neutrophils and macrophages

Most abundant WBC; Phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days. circulate in the blood

Amoeboid cells that roam connective tissue and engulf foreign particles and debris of dead cells. migrate through the body or reside permanently in organs and tissues

stimulate development of adaptive immunity

dendritic cells

discharge destructive enzymes against parasites likem worms

These circulate through the body and detect abnormal cells due to surface proteins of virus infected or cancerous cells
They release chemicals leading to cell death, inhibiting the spread of virally infected or cancerous cells
Many cellular innate defenses involve the lymphatic system

Natural Killer Cells

function in innate defense by attacking pathogens or impeding their reproduction

peptides & proteins

proteins provide innate defense, interfering with viruses and helping activate macrophages; inhibit viral replication;

About 30 proteins make up the ___________ system in the blood plasma, which causes lysis of invading cells and helps trigger inflammation

The ___________ ________, such as pain and swelling, is brought about by molecules released upon injury or infection

inflammatory response

____ cells, immune cells found in connective tissue, release histamine, which triggers blood vessels to dilate and become more permeable

Activated __________ _________ promote further release of histamine, attracting more phagocytic cells

complement proteins

Enhanced _____ ____ to the site helps deliver antimicrobial peptides

The result is an accumulation of ___, a fluid rich in white blood cells, dead pathogens, and cell debris from damaged tissues

______is a systemic inflammatory response triggered by substances released by macrophages in response to certain pathogens

_____ _____ is a life-threatening condition caused by an overwhelming inflammatory response

The adaptive response relies on two types of ___________, or white blood cells

Lymphocytes that mature in the thymus, above the heart, are called _ cells

lymphocytes that mature in bone marrow are called _ cells

________ are substances that can elicit a response from a B or T cell

T or B cells bind to antigens via _______ _________ specific to part of one molecule of that pathogen

antigen receptors

The small, accessible part of an antigen that binds to an antigen receptor is called an _______; B & T cells display specificity for epitopes

Each B cell antigen receptor is a Y-shaped molecule with two identical ______ chains and two identical _____ chains

The constant (C) regions of the chains vary ______ among B cells, whereas the variable (V) regions ______ greatly
The variable regions provide antigen specificity

Binding of a B cell antigen receptor to an antigen is an _____ step in B cell activation

This gives rise to cells that secrete a soluble form of the protein called an ________ or immunoglobulin (Ig)

Antibodies have the same _ shape as B cell antigen receptors but are secreted, not membrane bound

Each T cell receptor consists of ___ different polypeptide chains (called α and β)
The tips of the chain form a variable (V) region; the rest is a constant (C) region
T cell and B cell antigen receptors are ____________ different

two; functionally

Each T cell receptor consists of ___ different polypeptide chains (called α and β)
The tips of the chain form a variable (V) region; the rest is a constant (C) region
T cell and B cell antigen receptors are functionally different

T cells bind to antigen fragments displayed or presented on a host cell
These antigen fragments are bound to cell-surface proteins called major histocompatibility complex (___) molecules
___ molecules are host proteins that display the antigen fragments on the cell surface
In infected cells, ___ molecules bind and transport antigen fragments to the cell surface, a process called antigen presentation
A T cell can then bind both the antigen fragment and the ___molecule
This interaction is necessary for the T cell to participate in the adaptive immune response

The adaptive immune system has four major characteristics, what are they?

Immense diversity of lymphocytes and receptors
Self-tolerance: lack of reactivity against an animal's own molecules and cells
B and T cells proliferate after activation
Immunological memory

Antigen receptors are generated by ______ rearrangement of DNA
As lymphocytes mature in bone marrow or the thymus, they are tested for self-reactivity

Once activated, a B or T cell undergoes multiple cell divisions to produce a clone of identical cells

colonal selection

Some cells from the clone become _______ cells that act immediately against the antigen; Effector cells are plasma cells that secrete antibodies

The remaining cells in the clone become long-lived ______ cells that can give rise to effector cells if the same antigen is encountered again

is responsible for long-term protections against diseases

Immunological memory

The first exposure to a specific antigen represents the _______ immune response; clones are formed following this response

In the ________ immune response, memory cells facilitate a faster, more efficient response from a reservoir of T and B memory cells

In the _______ immune response, antibodies help neutralize or eliminate toxins and pathogens in the blood and lymph

In the ____-________ immune response, specialized T cells destroy affected host cells

A type of T cell called a ______ T cell activates both the humoral and cell-mediated immune responses
This requires the presence of a foreign molecule that can bind the antigen receptor on the helper T cell
And the antigen must be displayed on the surface of an antigen-presenting cell
Antigen-presenting cells have class I and II MHC molecules on their surfaces

Class II MHC molecules provide the molecular ________ by which antigen-presenting cells are recognized

Antigen receptors on the surface of ______-_ cells bind to the antigen and the class II MHC molecule; then cytokine signals are exchanged between the two cells
The helper T cell is activated, proliferates, and forms a clone of helper T cells, which then activate the appropriate B cells

The humoral response is characterized by secretion of antibodies by _ _____

__________ do not kill pathogens; instead, they mark pathogens for inactivation or destruction

In , ______________ antibodies bind to viral surface proteins, preventing infection of a host cell
Antibodies may also bind to toxins in body fluids and prevent them from entering body cells

In , ____________ antibodies bind to antigens on bacteria, triggering phagocytosis
Antigen-antibody complexes may bind to a complement protein, which triggers a cascade of complement protein activation

Ultimately, a membrane attack complex forms a pore in the membrane of the foreign cell, leading to its _____

_ cells can express five different forms (or classes) of immunoglobulin (Ig) with similar antigen-binding specificity but different heavy chain C regions

___ is membrane bound, while the other four, IgA, IgE, IgG, and IgM, are soluble

_________ T cells use toxic proteins to kill cells infected by viruses or other intracellular pathogens
_________ T cells recognize fragments of foreign proteins produced by infected cells
The activated _________ T cell secretes proteins that disrupt the membranes of target cells and trigger apoptosis

______ immunity develops naturally when a pathogen invades the body and elicits a primary or secondary immune response

_______ immunity provides immediate, short-term protection

Both _______ and _______ immunity can be induced artificially; EX: immunization

active; passive

__________ to nonself blood types exist in the body to act in defense; these proteins mark pathogens and cause inactivation or destruction.

________ are exaggerated (hypersensitive) responses to antigens called _________

allergies; allergens

In _________ allergies such as hay fever, IgE antibodies produced after first exposure to an allergen (such as pollen grains) attach to receptors on mast cells
The next time the allergen enters the body, it binds to mast-cell-associated IgE molecules

Mast cells release _________ and other inflammatory chemicals that bring about typical allergy symptoms

An acute allergic response can lead to ____________ _____, a life-threatening reaction, within seconds of allergen exposure
An injection of epinephrine can rapidly counteract the allergic response

anaphylactic shock

In individuals with __________ diseases, the immune system loses tolerance for self and turns against certain molecules of the body

______ immunodeficiency results from a genetic or developmental defect in the innate or adaptive defenses, or both
________ immunodeficiency develops later in life due to exposure to chemical and biological agents

inborn; aquired

Through _________ _________, some pathogens are able to change epitope expression and prevent recognition; EX: Flu, AIDS,

antigenic variation

Some viruses may remain in a host in an inactive state called _______

_____ ________________ _____ (HIV) infects helper T cells
HIV persists in the host—despite an immune response—because it has a high mutation rate that promotes antigen variation
Over time, an untreated HIV infection not only avoids the adaptive immune response, but also abolishes it; people with aids are immunodeficient and susceptible to opportunistic hosts.

Human immunodeficiency virus

Each activated B or T cells makes many clones of itself; some of these become ________ cells which take immediate action against pathogens

the remainder of activated cells become ______ cells which live long and can give rise to effector cells upon the second detection of the same antigen

The _______ immune response takes place in the blood and lymph in which antibodies neutralize or eliminate the toxins or pathogens

specialized T cells destroy infected host cells

cell-mediated immune response

what types of cells can be antigen-presenting cells?

dendritic cells; macrophage; or B cells

An immune response in which the binding of antibodies to the surface of a microbe facilitates phagocytosis of the the microbe by a macrophage or neutrophil

use toxic proteins to kill cells infected by viruses or other intracellular pathogens prior to their maturity

cytotoxic T Cells

the defenses that arise when a pathogen infects the body and prompts a primary or secondary immune response

active immunity

When antibodies are introduced into the body. (from mother to infant through breast-feeding). Short term immunity

passive immunity

produced by such a culture are identical and specific for the same epitope on an antigen

monoclonal antibodies

What are some examples of things that would negatively effect the immune system?

Lack of sleep
stress
over-exercise

moderate _________ can improve immunity

_______________controls solute concentrations and balances water gain and loss

_________ rids the body of nitrogenous metabolites and other waste products; humans excrete nitrogen through urea

__________the solute concentration of a solution, determines the movement of water across a selectively permeable membrane

_______________are isoosmotic with their surroundings and do not regulate their osmolarity

______________ expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment

The _________,_________ & ____________ produce most of the sex hormones: androgens, estrogens, and progesterone

gonads, testes & ovaries

The testes primarily synthesize androgens, mainly _____________, which promote development of male reproductive structures; secondary sex characteristics

Estrogens, most importantly ____________, are responsible for maintenance of the female reproductive system; secondaery sex characteristics

In mammals, _______________ is primarily involved in preparing and maintaining the uterus

Synthesis of the sex hormones is controlled by the ___________________, follicle-stimulating hormone and luteinizing hormone from the anterior pituitary;

The frequency of certain cancers increases when ________immunity is inactivated

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