Chapter 12 Immunology Flashcards
the work of Jenner and Pasteur
principle of prior exposure to related or attenuated microorganisms leading to protective immunity
major histocompatibility complex (MHC) proteins
The immune system’s most important role is to distinguish between “self” and “nonself” and to remove foreign molecules and organisms that invade the body.
Characteristics of self are attributed to macromolecules on cell surfaces
antigen
Pathogens, proteins from a genetically different individual, or other substances
antigenicity
The degree to which an antigen can induce an immune response
The main parts of the immune system where leukocytes are generated:
the thymus,
the bone marrow,
the liver, and
the spleen.
Innate immunity
provides the first line of defense against invading foreign substances. This immunity consists of physical, biochemical, or cellular agents which are natural body defenses that detect and neutralize potential invaders.
reactive proteins
complement proteins
circulate in blood and tissue spaces in inactive forms
These proteins adhere to the surface of the invading organisms and facilitate an attack by phagocytic cells.
interferons
chemicals that carry out communication among cells
three types of interferons:
alpha,
beta, and
gamma.
neutrophils
macrophages and granulocytes
Macrophages and granulocytes release cytokines
Macrophages and granulocytes also initiate phagocytosis to engulf these foreign cells.
epitope
antigen fragment
2 kinds of acquired immune response
Cell-mediated response
Antibody-mediated response
Cell-mediated response
where most types of specialized lymphocytes, called T cells, stimulate the immune response through several pathways. They secrete cytokines (different from interferons) that stimulate the immune response in other cells. T cells release cytotoxic molecules that destroy foreign cells, cancer cells, and the body’s own injured cells. T cells are also necessary to stimulate B cells, inducing them to evolve into plasma cells for the production of antibodies.
Antibody-mediated response
where plasma cells (stimulated B cells) secrete antibodies that neutralize or destroy the infectious agents. The antibody-mediated response is often called the humoral immune response because the antibody-antigen interaction occurs in the fluids outside the cells; humoral means “body fluids.”
Amplification
the second step, is where the immune response increases in magnitude. Pathogen-specific T-cells proliferate; B-cells mature into plasma cells, magnifying the antibody titer; and the activating signal is transmitted from the T cell receptor to other molecules and cells in the animal.
Chemokines
mediate cell traffic, directing the movement of the immune cells throughout the lymphatic system.
cytokines
induce the antigen-specific T cells to proliferate and attack the pathogen, whereas others produce the redness, pain, and heat that are associated with the body’s inflammatory response.
resolution
the immune system has eliminated the threat to the body. The infected cells, parasites, or pathogens are dead
Macrophages
are a component of the innate immune system. Macrophages are phagocytes which engulf foreign materials, digest them into smaller pieces (breaking proteins into peptides, for example), and present these antigens to other cells of the immune system. As antigen-presenting cells (APCs), they promote the activities of cells in the acquired immune system. They offer a nonspecific response to substances recognized as nonself and often initiate the inflammatory response that will ultimately rid the body of the invading agent.
Granulocytes
include neutrophils, eosinophils, mast cells, and basophils. Neutrophils destroy invading cells by engulfing them (for example, bacteria) or releasing the contents of lysosomes onto them (for example, parasites and cancer cells). They respond to cytokines and other signals from antigen-presenting cells. They support the activities of cells in the acquired immune system. Mast cells and eosinophils play a role in inflammatory and allergic reactions. They release potent inflammatory mediators, such as histamine.
Dendritic cells
have a major role in initiating an immune response. Their role is similar to that of macrophages. They act as antigen-presenting cells, trapping the antigens on their surface, migrating to lymph nodes, and presenting the antigens to other lymphoid cells to initiate a response.
B lymphocytes (B cells)
provide antibody-mediated immunity. These cells originate from bone marrow in higher vertebrates and from an organ called the bursa of Fabricius in birds. (B cells were named for this bursa.) When activated, B cells develop into plasma cells that produce and secrete antibodies that bind to antigens and mark them for destruction. B cells and plasma cells are part of the humoral response of the acquired immune system.
T lymphocytes (T cells)
develop in the thymus and provide cell-mediated immunity. They attack and destroy diseased cells which they identify as foreign. T cells have special molecules on their surface (T-cell receptors), which help them recognize and attach to antigens.
Antibodies
are immunoglobulins (Ig, pronounced as the letters “I” and “G”), which are glycoproteins (protein + carbohydrate) that bind to antigens in what is known as the antibody-antigen complex.
five classes of immunoglobulins in mammals
IgG, IgM, IgA, IgE, and IgD.
two major classes of immunoglobulins in birds, reptiles, amphibians, and fish
IgY (which is similar to IgG) and IgM.
IgG
The most abundant immunoglobulin in serum; found only in mammals. Only IgG can cross the placenta; in humans and rabbits, it is responsible for protecting the fetus and the newborn animal in the first few weeks of life before the neonate’s own immune system develops.
IgM
The second most abundant type of serum antibodies in mammals; also present in birds, reptiles, amphibians, and fish. IgM is a large antibody and is mostly confined to the blood. IgM is the first immunoglobulin class to be synthesized by a fetus or newborn and the first antibody to be detected in response to an initial exposure to an antigen.
IgA
The predominant type of antibodies found in mammalian body secretions (bile, tears, saliva, colostrum) and in the fluids which bathe the mucous membranes of the intestines, lungs, and urinary tract. IgA is resistant to digestion and attacks pathogens that contact the body surface, are ingested, or are inhaled.
IgE
Found on the cell membranes of basophils and mast cells in mammals. Although IgE is typically found in low concentration, it triggers the most powerful immune reactions and is associated with immediate hypersensitivity reactions such as allergic reactions and asthma. Levels of IgE increase during parasitic infections.
IgD
Found in low concentration in serum, its function is not known. IgD is almost exclusively found in the membranes of B cells, where it may have a role in these cells’ activation. However, mice lacking IgD seem to retain normal immune responses.
IgY
A class of antibody occurring in birds, reptiles, amphibians, and fish. It is equivalent to IgG in mammals. Egg yolk is rich in IgY; thus, chicken eggs are a common source of antibody used in immunological studies.
Cell-mediated immunity
is the generation of active lymphocytes that work to destroy infectious agents, parasites, foreign cells, or other antigens. This is the most complex branch of the immune response because it uses some components of the innate and humoral immune response. It is essential for the generation of humoral immunity.
Passive immunization
is accomplished by transferring preformed antibodies from an immune animal to a nonimmune animal. This occurs naturally when a fetus receives antibody across the placenta or when a neonate ingests colostrum (first milk).
Active immunity
is what the animal produces in response to being exposed to a foreign antigen. Immunization, such as by inoculation with a vaccine, ensures a protection that lasts longer than passive immunity.
primary immune response
The production of antibody from a first exposure to an antigen
Lineage B Cell
Develops into a plasma cell. Produces antibody.
Lineage T Cell
Regulates the antibody-mediated response.
Kills cells.
resume text book flash cards after Lineage T cell
resume text book flash cards after Lineage T cell
which type of immune cells do athymic nude mice lack?
t cells
when an animal begins to make antibodies against itself, the resulting clinical state is what type of disease?
autoimmune
the secondary immune response is also known as….
memory
what substance is used to boost the effectiveness of vaccines?
adjuvants
t or f: an inherited defect in immune response is known as a primary immunodeficiency disease.
true
the primary function of b cells is to produce what type of molecules?
antibodies (or immunoglobulins)
the immune system’s chemical messengers are called….
cytokines
there are two kinds of t cells:… and….
helper and killer
antibody production has 4 phases: lag, log, …… and decline.
plateau
which class of immunoglobulin is responsible for allergic reactions?
IgE
an organism that is weakened and unable to cause disease is referred to as….
attenuated
what substance is recognized as non-self and can elicit an immune response?
antigen