SAC 4 Immunity Case Study

Active Immunity

Immunity produced by exposure to an antigen, as a result of the immune response. It can be induced - individual receives vaccination of a dead or attenuated form of a pathogen, acquired - memory cells made as a result of a prior infection, and innate - immunity that is present but isn’t due to prior exposure to an antigen (first line of defense, etc.).

Adaptive Immunity

The ability of the body to recognize and remember specific antigens and mount an attack on them

Agglutination

Clumping of microorganisms or cells, typically due to an antigen-antibody interaction

Antibody

An antigen-binding immunoglobulin, produced by B cells, that functions as the effector in an immune response

Antigen

Substance that triggers an immune response

Antigen presenting cells

Dendritic cells, macrophages, B cells

Artificial immunity

Acquired through a medical procedure such as a vaccine or injected antibodies/plasma B cells

B lymphocytes

Form in the bone marrow and release antibodies that fight bacterial infections

bacteria

single-celled organisms that lack a nucleus (prokaryotes)

Basophils

A circulating leukocyte that produces histamine

Cell-mediated response

The branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against virus infected cells

Cellular barriers

commensal micro-organisms

Chemical barriers

Proteins that destroy pathogens at the body’s surface

Clonal expansion

the rapid multiplication/proliferation of B or T cell clones after the activation by an antigen

Clonal selection

The process by which an antigen selectively binds to and activates only those lymphocytes bearing receptors specific for the antigen

Complement proteins

A number of different types of proteins found in the blood that opsonize, cause lysis, and attract phagocytes to invading pathogens

Cytokines

Chemicals released by the immune system due to pathogen presence or cell damage, that are signaling molecules that communicate with other cells

Cytotoxic T cells

Destroy pathogens and release chemicals called cytokines

Degranulation

The emptying of granules from the interior of a mast cell into the extracellular environment

Dendritic cells

Antigen-presenting cells in the skin

Eosinophils

A white blood cell containing granules that are readily stained by eosin

Epidemic

A widespread outbreak of an infectious disease

Fever

Elevated body temperature

First line of defense

Intact skin, mucous membranes and their secretions, normal microbiota

Fungal pathogens

Eukaryote species with chitin cell walls that can cause disease in plants and/or animals

Granulocytes

A group of leukocytes containing granules in their cytoplasm (mast cells, eosinophils, basophils)

Granzymes

Enzymes that attack proteins of target cells and induce apoptosis

Helper T cells

Help the immune system by increasing the activity of cytotoxic T cells, B cells, and stimulating the suppressor T cells

Herd immunity

The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune

Histamine

Chemical stored in mast cells that triggers dilation and increase permeability of capilleries

Humoral response

The branch of acquired immunity that involves the activation of B cells and leads to the production of antibodies, which defend against bacteria in bodily fluids

Inflammatory response

Non-specific defense reaction to tissue damage caused by injury or infection, characterized by redness, heat, swelling and pain.

Innate immunity

Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens

Interferon

Protein produced by cells in response to being infected by a virus (helps other cells resist the virus)

Interleukins

Proteins (cytokines) that stimulate the growth and activation of B and T lymphocytes

Lymphatic system

Composed of a network of vessels, ducts, nodes and organs. Provides defense against infection

Lymph nodes

Bean-shaped filters that cluster along the lymphatic vessels of the body. They function as a cleanser of lymph as well as the site of T and B cell activation

Macrophages

Phagocytize foreign substances and help activate helper T cells

Mast cells

Cells that release chemicals (such as histamine) that promote inflammation

membrane attack complex (MAC)

The complex of terminal complement proteins that forms a pore in the membrane of the target cells, damaging the membrane and leading to cell lysis

Memory B cells

Produced during a B cell response, but aren’t involved in antibody production during the initial infection. Are held in reserve for the rest of your life in case you encounter the pathogen again

Memory T cells

Remembers antigen and quickly stimulates the cell-mediated branch of the immune response upon re-exposure/secondary exposure

MHC 1 proteins

Found on all nucleated cells, and are necessary for cell recognition

MHC 2 proteins

Occur only on APC’s and display only foreign antigens

Naive B cells

B cells that have the ability to produced an antibody specific to an antigen but which wait in the lymph nodes until their particular antigen comes along and activates them

natural immunity

Acquired as a part of normal life experiences

Natural killer cells

A type of white blood cell that can kill tumor cells and virus-infected cells. An important component of innate immunity

Neutralization

Process where antibody binds to toxin/pathogen and prevents it from damaging the host cells

Neutrophils

The most abundant type of white blood cells. They are phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days

opsonisation

Process in which a pathogen is coated with antibodies and/or complement and marked for phagocytosis

Pandemic

Disease that occurs over a wide geographic area and affects a very high proportion of the population

Passive immunity

The short-term immunity that results from the introduction of antibodies from another person or animal

Pathogen

A disease causing agent

Perforin

A protein, released by killer cells of the immune system, that destroys targeted cells by creating lesions like pores in their membranes

phagocytes

A type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Physical barriers

Skin and mucous membranes

Plasma B cells

B cell proliferates by mitosis to produce these cells, which produce and secrete the specific antibody that exactly fits the antigen on the pathogen’s surface

Primary exposure

First exposure to a pathogen

Primary lymphoid tissue

Bone marrow and thymus

Prions

Infectious proteins

Proliferation

Rapid increase in numbers

Protist pathogens

Eukaryotic cellular pathogen (Malaria)

Second line of defense

Protective cells and fluids (inflammation and phagocytosis). It’s non-specific

Secondary exposure

A second exposure to the same infective agent or pathogen

Secondary lymphoid tissues

Has the role of filtering lymph

T cell receptor

Antigen receptors on a T cell. Unlike antibodies, these are never produced in secreted form

T lymphocytes

Mature in the thymus

Third line of defense

Adaptive immunity

Transmission

Transfer, such as a disease, from one person to another

Vaccination

Injection of an attenuated form of a pathogen to produce immunity

Virus

A tiny, non-living particle that invades and then reproduces inside a living cell