Terms Module 1 Flashcards
The study of chemical and cellular defense against foreign substances
Immunology
foreign substance, such as a microorganism, which triggers the immune response
Antigen
Specific response to “foreign” substance (usually a microbe)
Adaptive (Acquired / Induced) Immunity Response
antigen-specific proteins which bind to the antigen and assist in inactivating the antigen
Antibody (Ab) [Immunoglobulin (Ig)]
a sequence of related host defense events beginning when a host encounters a substance as being “foreign” or “non-self” and leading to cellular and chemical defensive actions.
Immune Response
the body’s resistance to disease-causing microorganisms and damage by foreign substances
Immunity
certain white blood cells that ingest and digest (kill) invading microbes
Phagocytes
Non-specific, general recognition and response to “foreign” substance. Physical and chemical barriers (e.g. skin & mucous; certain proteins in blood and from specific tissue cells; inflammation, phagocytosis)
Innate Host Response (Natural/Native immunity)
The primary phagocytic cells
Neutrophils
Moderately phagocytic; matures into macrophages & dendritic cells; and responds to inflammation signals
Monocyte
Nonspecific, general response to “foreign” substance, including inflammatory response
Innate Host Response (Natural/Native immunity)
precommitted to respond to specific antigens
Lymphocytes
numerous in allergic responses
Eosinophils
involved in the inflammatory process
Basophils
antigenic substance is engulfed and digested by certain white blood cells.
Phagocytosis
Lymphatic fluid containing antigens and Antigen-Presenting Cells flows through _______ where the antigens encounter and activate precommitted lymphocytes and respond to local or regional infections
Lymph nodes
the passage of blood cells through the intact walls of the capillaries, typically accompanying inflammation.
Diapedesis
(MALT)
Mucosal-Associated Lymphoid Tissue
movement of phagocyte toward the site of inflammation/intrusion; “called” by cellular products
Chemotaxis
a process by which leukocytes stick to the walls of blood vessels at the site of an infection
Margination
Filters blood and traps blood-borne antigens – responds to systemic infections
Spleen
tissues where antigens interact with cells of the immune system
Lymphoid Tissue
(one amino acid chain) found on virtually every cell in the body
Class I MHC
(BALT)
Bronchus-Associated Lymphoid Tissue
A specific “foreign” substance which stimulates an immune response (immunogenic) when introduced into the body, and reacts with antibodies or T-cell receptors.
Immunogens
proteins on the surface of tissue and blood cells which identify cells belonging to a specific individual.
Major Histocompatibility Complex proteins (MHC)
(GALT)
Gut-Associated Lymphoid Tissue
the specific part of the immunogen that specifies or determines the exact antibody to be produced
Epitope
Recognition of Self vs. Non-self is determined by
Major Histocompatibility Complex proteins (MHC)
(two amino acid chains) found only on immunocompetent cells, particularly B-cells and macrophages
Class II MHC
amino acid sequences vary from one immunoglobulin to another; match with variable region of corresponding heavy chain
Variable region (VL )
specific to the antigen to which this cell is ‘precommitted’ and they develop as attachment sites for specific types of foreign antigen molecules
Antigen-Specific Surface Receptors (T-cell Receptors [TCR] or B-cell receptors [BCR])
antigen-specific binding sites – “lock and key” specificity for specific antigen
Fab sites
The mature lymphocytes will be tolerant of antigens on our own “self” MHC molecules; and, therefore, will not mount an immune response against them.
Immune Tolerance
Antibody that region binds to phagocyte
Fc region
antigen-specific proteins which bind to specific sites on antigens and assist in inactivating the antigen by attaching to it.
Immunoglobulins (Ig) [Antibody (Ab)]
Two types (2 sequences) – Kappa and Lambda types (4 subtypes)
Constant region (CL)
LFA-1
Leukocyte Function-associated Antigen-1
capture antigenic material (whole microbes) via phagocytosis
Macrophages
Amino acid sequence and 3-dimensional structure accounts for ability to recognize and bind with a particular epitope
Variable region (VH)
small proteins produced by specific human cells and which act as chemical mediators of the immune system to cause or enhance certain actions or functions of the immune system.
Cytokine Products of Cells
capture “digested” antigenic material via antigen-specific B-cell receptors
B-lymphocytes (B-cells are not phagocytic)
chemicals which help activate or control the cells of the immune system
Chemical Mediators
Antigen-specific immunoglobulin response
Characteristics of TH2
a proteoglycan which serves to assemble a complex containing granzymes and perforin
Serglycin
defensive activities based on the role of antigen-specific immunoglobulins
Humoral Response
a membrane-penetrating protein which creates an entrance into the target cell
Perforin
Antigen-specific local inflammatory response
Characteristics of TH1
cytotoxic protease molecules which cleave various proteins in the target cell’s cytoplasm thus leading to apoptotic death of the target cell
Granzymes
Defensive activities based on the action of pre-committed T-lymphocytes that move into action to kill the invader or activate other parts of the immune system through the production of chemicals which directly fight (act to kill) the antigen (microbe) or regulate immune response
Cell-Mediated Response
the immunoglobulin-producing progeny of an activated B-lymphocyte (lives only a few days; produces 20,000 molecules per minute)
Plasma cells
gene rearrangement leading to the expression of a new heavy chain class (switch from IgM to IgG or IgA) without altering the specificity (Fab) of the immunoglobulin
Class Switching
immunoglobulins alter the shape of toxin molecules, thus rendering them ineffective (activity of IgG only)
Neutralization of toxins
the attachment of immunoglobulin molecules to the surface of an antigen (e.g. bacterial cell), thus marking the cell for rapid phagocytosis and increasing the phagocyte’s adherence to the cell.
Opsonization
long-lived and self-renewing cells which “remember” the antigen and remain primed for future encounters with it
Memory T-lymphocytes (TM)
a tissue cell that has high-affinity receptors for IgE and generates inflammatory chemical mediators in allergy
Mast Cell
reaction limited to a specific target tissue or organ, often involving epithelial surfaces at the site of allergen entry (e.g. hay fever)
Localized anaphylaxis
a shock-like and often fatal state whose onset occurs within minutes or exposure to the allergen (e.g. bee sting)
Systemic anaphylaxis
A complex series of serum proteins which interact in a cascade fashion to enhance certain antigen-antibody reactions.
Complement System
destruction of cells by means of membrane-attack complexes
Cytolysis
the events which occur in the host’s immune system following first time exposure to a specific foreign substance.
Primary response
chemical attraction of phagocytic cells to the site of antigenic stimulation.
Chemotaxis
the rapid and highly specific response by the host’s immune system against a specific foreign substance which had been previously encountered.
Secondary response
increase adherence of phagocytes to the antigen
Phagocyte adherence (opsonization)
Results from direct stimulation of host immune system
Active immunity
Results from transfer of pre-formed immunoglobulins and/or cells from a donor to the host. Host immune system does not participate.
Passive immunity
active infection caused the host to produce immunoglobulins in response to the infection;
Active natural
preformed immunoglobulins acquired by placental transport of mother’s Ig G to fetus, or by colostrum (Ig A) in the mother’s milk
Passive natural
host produces immunoglobulins in response to immunization (vaccination) with live or killed microorganism
Artificial active
pre-formed immunoglobulins acquired by injection of antiserum or antitoxin
Artificial passive
a class of bacterial toxins and viral proteins that can non-specifically bind the MHC-II molecule of an APC with the TCR of a T-cell in a tight adhesion of the two cells, thus leading to massive T-cell activation and the release of large amounts of cytokines
Superantigens
immune responses that fail to
distinguish self from non-self
Autoimmune diseases
defects in defensive immunological reactions manifested by recurring infections.
Immunodeficiency diseases
immune responses that are exaggerated or inappropriate for protective function (e.g. fatal bee sting)
Hypersensitivity
Antigen-antibody complexes deposit on the cell membrane and activate complement and an ensuing inflammatory response
Type III – Immune Complex-mediated Hypersensitivity
Immunoglobulins directed against antigens on an individual’s cells cause complement lysis or destruction by killer cells
Type II – Antibody-mediated Cytotoxic Hypersensitivity
Antigen-sensitized T-cells release lymphokines after being re-exposed to the antigens. The lymphokines attract macrophages which in turn release mediators and induce an inflammatory reaction. (24-72 hours)
Type IV – Cell-mediated Hypersensitivity (delayed type hypersensitivity)
IgE sensitized mast cells degranulate when re-exposed to an antigen
Type I – IgE-mediated Hypersensitivity (immediate hypersensitivity)
a subset of cytokines that are produced by a type of immune cell known as a lymphocyte
Lymphokines
