immunology

Proteins synthesized by the liver in response to IL-6 (produced by macrophages in response to infection) and released into the blood stream, including CRP, MBL, fribrinogen and SAA.

The strength of binding for antigen of one antigen combining site (aka one arm of an antigen).

The average affinity for a population of antibodies will increase with repeated immunization with antigen (selection for greater affinity variations of the variable region brought on by random mutation – immunology form of natural selection). 

Differences in the constant regions of antibodies (of the same isotype) between different individuals due to the presence of multiple aleals of the constant region genes.

A series if enzyme reactions triggered by foreign surfaces leading the generation of the alternate C3 convertase (C3bBb).

Complement fragments with the ability to stimulate mast cell degranulation.

Protein molecule that is synthesized on exposure to antigen and that combines specifically with that antigen.

A cytotoxic reaction in which natural killer cells and macrophages recognize antibody-coated target cell through the Fc region on IgG via their Fc receptor.

the reciprocal of the last dilution of antiserum that yields a demonstrable antibody binding reaction.

A molecule which induces the formation of antibody.

A cell which carries antigen in a form that can stimulate lymphocytes. Dendritic cells, macrophages and B cells are all APCs.

Serum containing specific antibodies.

Immunity to self antigens.

The functional combining strength of an antibody with its antigen which is based on both affinity and valences of the antibody. Increased affinity that occurs as result of multiple antigen binding sites on an immunoglobulin (IgM has greater avidity than IgG).

Granules in neutrophils which contain acid hydrolases, myeloperoxidase, and lysozyme. (See also specific granules.)

A subset of lymphocytes responsible for humoral immunity. B cells develop in the bone marrow. Antigen naïve B cells have IgM and IgD on their membrane surface and are the precursors of plasma cells (antibody producing cells). Each B lymphocyte has only one antigenic specificity.

A granulocyte with deep violet or blue-black staining granules. Basophils are generally associated with the inflammatory response. 

The layer of white blood cells immediately above the red blood cells in a tube of blood following centrifugation.

Primary lymphoid organ; site of education and maturation of B cells in birds; Bone marrow is the equivalent in mammals.

The process of initiating the complement cascade.

An interlinked series of enzyme reactions in which the products of one reaction catalyze a second reaction, and so forth.

Cluster designation antigens.

Marker specific for T helper cells that recognize class II MHC.

Marker specific for CTLs that recognize class I MHC.

Immunity in which the participation of lymphocytes and macrophage is predominant.

Molecules which attract a specific type of cell to the point of highest concentration (C5a, Leukotriene B4, Chemokines, Bacterial lipids and protein)

Proteins expressed on nearly all nucleated cells (except erythrocytes and corneal epithelium). These surface proteins are designed to present smaller endogenous peptide antigens to signal that a cell is has been infected with virus or has become a tumor cell to illicit a CTL response (CD8+ cells). 

Proteins expressed on professional antigen presenting cells (APCs) including dendritic cells, macrophages and B cells. These surface proteins are designed to present larger exogenous peptide antigens to illicit a T-helper cell response (CD4+ cells).

A series of enzyme reactions triggered by the binding of C1 to an immune complex, leading to the generation of the classical C3 convertase (C42). Requires the 2 IgG molecules or 1 IgM molecule.

A family of cells descended from one "parent" cell; all are genetically identical.

Functional inactivation of viable lymphocytes.

Death of antigen-specific lymphocytes.

One of the mechanisms accounting for diversity in immunoglobulins. Different copies of gene segments exist that can be rearranged in many ways.

A complex linked enzyme system that is activated by such factors as the combination of antigen and antibody and that results in a variety of biological responses.

The invariant parts of immunoglobulin heavy and light chains.

The outer part; applies to the thymus and lymph node.

An specific area on the surface of an antigenic molecule that is recognized by an antibody.  

A fragment of immunoglobulin resulting from pepsin digestion; consists of N-terminal halves of heavy chains and whole light chains and a portion of the hinge region. A single F(ab’)2 fragment is formed from pepsin digestion of an antibody. It has two antigen binding sites.

Fragment of antibody. That part of the immunoglobulin consisting of the N-terminal half of the heavy chain and its associated light chain; results from papain digestion. Two Fab fragments are produced from papain digesion. Each fragment has one antigen binding site.

Fragment crystallizable. That part of the immunoglobulin consisting of the C-terminal half of the heavy chains, containing the constant domains. One Fc fragment is formed from papain digestion.  This portion determines the isotype of the molecule. 

A clonal expansion of an activated B cell seen within a secondary follicle.

A leukocyte with large numbers of cytoplasmic granules and a multi-lobed nucleus. The include neutrophils, eosinophils, and basophils.

The complete set of alleles at all loci within a gene complex on a single chromosome.

A small molecule that cannot initiate an immune response (aka antibody formation) unless first bound to an immunogenic carrier molecule. However, once a response is initiated, a hapten can react specifically with its antibody. Haptens are antigens not immunogens.

The larger of the two types of chains making up an immunoglobulin molecule; consisting of one variable domain and three to four constant domains.

A vasoactive agent released by basophils, mast cells, and platelets.

Cell membrane proteins that provoke an immune response when a tissue is grafted into an allogeneic recipient.

Human leukocyte antigen. The human MHC.

Immunity in which antibody plays the significant role.

Small segments with immunoglobulin variable regions where great variations in amino acid sequence occur.

The antigenic characteristic of the variable region of an immunoglobulin (from contributions of the heavy and light chains).  

Antigen-antibody complexes.

The concept that lymphocytes survey the body for abnormal cells and foreign invaders and then eliminate them.

Free from disease or the state of resistance to an infection.

The ability of a substance to elicit an immune response. The addition of an adjuvant will prolong the retention of an molecule in a body to create a more vigorous immune response.

A glycoprotein composed of H and L chains that functions as antibody. All antibodies are immunoglobulins; the converse may or may not be true.

Branch of science devoted to the study of host defenses against infectious disease and neoplasm and the undersirable consequnces of immune interactions (eg. Autoimmunity or anaphylaxis).

A reaction of the tissues and its microvasculature to some type of insult such as infection, injury or toxin. Results in  complex set of reactions caused by cells and soluble factors which are characterized by rubor, calor, tumor, dolor (redness, heat, swelling, and pain).

A heterogeneous group of low molecular weight proteins released by virus infected cells which protect non-infected cells.

The types of immunoglobulin molecules common to all members of a species.

Nucleotide addition and removal occurs at the joints between gene segments that are recombined.

A specialized antigen presenting cell with characteristic tennis racket shaped granules; found in the epidermis (considered dendritic cells).

A white blood cell. This general term covers all the nucleated cells of mammalian blood.

Metabolites of arachidonic acid produced by the actions of lipoxygenase. Ex. Leukotriene B4: Chemotatic factor.

Secondary lymphoid organ; major filtering organ for interstitial fluid and lymph; site of immune response to antigens isolated and processed.

A mononuclear cell with a round nucleus containing densely packed chromatin. Most have very little cytoplasm. Include T, B and NK cells which cannot be distinquished morphologically.

The homing process refers to the propensity for lymphocyte populations to take up residence preferentially in certain lymphoid organs or tissues.  Homing is dependent upon specific “addressins” expressed by lymphocytes that allow the cells to bind to the site that specifically binds those addressins

• A cell subset of NK cells (in response to a high dose of IL-2) that have enhanced tumor cell cytolytic capability. 
• lymphotoxin Cytotoxic factors released by lymphocyte

The cationic low-molecular weight enzyme present in tears, saliva, and nasal secretions that reduces the local concentration of susceptible bacteria by attacking the mucopeptides of their cell walls.

A phagocytic mononuclear cell derived from monocytes; serves accessory roles in cellular immunity.

A genetic region which is responsible for rapid rejection of grafts between individuals; codes for membrane bound proteins on nucleated which function in signaling between lymphocytes and APCs.

Also called immune resonse (Ir) genes. They control the protein antigens to which an individual can respond to.

The total set of MHC genes on each chromosomes. Each individual inherits one haplotype from each parent (polygenic).

MBl reszembes C1 of the classical pathway. Mannose residues on the surface of pathogens are required for activation to complete the complement cascade.

The inner part; applies to the thymus and lymph node.

Found in lymph nodes; provide anchorage for macrophage and plasma cells.

Immunoglobulin formed from a cloned population of cells. These antibodies bind to only one specific antigen.

A phagocytic mononuclear cell derived from myeloid stem cells; found in circulating peripheral blood.

A subset of lymphocytes capable of killing tumor cells and virus infected cells. Also can mediate ADCC.

Blockage of the activity of an organism or a toxin by antibody.

A phagocytic granulocyte with a prominent multi-lobed nucleus; usually the first cell type responding to injury or infection.

A substance that facilitates the phagocytosis of foreign particles.

C3b, immunoglobulin, CRP, MBL

A family of proteins that has the ability on polymerization to form tubes which insert into cell membranes and provoke cell lysis.

Found in spleen; organized clusters of B cells in follicles surrounded by T cells and macrophage which occur in association which splenic arterioles.

A specialized aggregate of lymphocytes and M-cells in the gut; the major part of GALT (gut MALT).

A cell which eats.

The act of eating; refers to the ingestion of particulate matter.

A vacuole in the cytoplasm containing the engulfed meal.

The act of drinking; refers to the ingestion of soluble matter.

An end-stage cell of B cell lineage which makes and actively secretes antibody.

The fluid phase of blood containing full range of circulating proteins, including clotting factors and fibrin.

A population of antibodies which (collectively) can bind to more than on particular antigen.

Inherited structural differences between proteins from allogeneic individuals. A form of allotypic variation.

A neutrophil.

represent those sites that support the generation of functionally mature, but antigen naïve, T and B cells. Development of antigen-recognition occurs at these sites as a consequence of rearrangement of antigen receptor genes (i.e. immunoglobulins and TCR). Examples of primary lymphoid tissue include the bone marrow and thymus.

Metabolites of arachidonic acid produced by cyclooxygenase.

A substance which causes fever; may be endogenous or exogenous.

Part of the spleen; contains resident macrophage which phagocytize effete red blood cells and particulates found in the blood as it filters through the sinuses.

The increase of metabolic activity that takes place in phagocytic cells at the time of ingestion; highly reactive microbicidal agents  (superoxide anion and it’s derivatives) are produced which are released into the phagosome.

represent locations where naive lymphocytes reside while waiting to be activated by their specific antigens. These tissues are designed to funnel antigen that enters the body into the collection of antigen-specific B and T lymphocytes to drive the antigen-dependent activation and differentiation of naive T and B cells into effector and memory cells populations. Examples of secondary lymphoid tissue include lymph nodes, tonsils, Peyer’s patches, and the spleen.

The fluid phase of blood containing all circulating proteins except those involved in clotting.

Granules found in neutrophils which contain lactoferrin and some lysozyme.

Secondary lymphoid organ; filters particulates and antigens from blood as part of the reticuloendothelial system.

Synonymous with isotype. Subdivisions of the immunoglobulin classes.

A complex of two peptides which function to recognize antigenic determinants and to initiate a response. In TcR2, two peptides, alpha and beta, are linked by one disulfide bond and function much like an immunoglobulin in binding antigen; in fact, these two peptides are part of the immunoglobulin superfamily. TcR complexes are closely associated with CD3, made up of at least three other peptides, gamma, delta, and epsilon, which are involved in signal transduction after the antigen is bound.

A lymphocyte educated in the thymus; involved in cellular immunity and in regulating all immune responses, both humoral and cellular. T cells can only recognize antigen presented on APCs.

constitute sites of the body where the elimination of antigen takes place. These sites comprise the “battlefield” on which the immune system defends the tissues from microbial invasion. These tissues, such as the skin and mucosal lining of the gastrointestinal, pulmonary, and genitourinary tracts, have direct contact with the external environment. Examples include the skin, gastrointestinal tract, lungs, and vagina.

Final lymphatic collecting vessel which empties into the left subclavian vein

The central lymphoid organ that is located in the thorax which controls the ontogeny of T cells. Primary lymphoid organ responsible for the education and maturation of T cells.

The thymocyte population expresses all possible antigen specificities due to the random gene recombinations required to generate the T cell antigen receptor.  Therefore, T cells that are self-reactive are present and need to be deleted from the population. Positive and negative selection produces the desired T lymphocyte that will react only with foreign antigen in the context of self MHC proteins.

The reciprocal of the highest dilution of a serum that gives a reaction in an immunological test.

The measurement of the level of specific antibodies on a serum by testing increasing dilutions of the serum for antibody activity.

Tolerance is a block in the growth and differentiation of lymphocytes brought about by antigen (called tolerogen, as opposed to an immunogen which stimulates an immune response). It is an induced state of unresponsiveness to antigen.

Products of lymphocytes and macrophage that can exert a direct toxic effect on neoplastic cells.

That part of the immunoglobulin peptide chains where the amino acid sequence shows significant variation between molecules.

Molecules which effect the vascular permeability and/or the level of vasodilation/vasoconstriction.

The nucleated cells found in blood.

Part of spleen; see periarteriolar lymphoid sheath.

antibody

antibody dependent cellular cytotoxicity

Antigen

antigen presenting cell

acute phase protein, produced by liver

Acute Phase Response

bone marrow (“bursa”)-derived lymphocyte

Constant

Complement

complementary determining regions (hypervariable region)

cell mediated immunity

C-reactie protein (APP)

cytotoxic lymphocytes

disseminated intravascular coagulation

enzyme-linked immunosorbent assay

fragment of antibody; from papain digest

fragment resulting after pepsin digest

fluorescent-activated cell sorter

constant region made of the heavy chain on an immunoglobulin (Fc receptors are located on cell that recognize this region on immunoglobulin for ADCC). 

variable region made of the heavy and light chain on an immunglobulin

graft versus host (disease)

chain heavy chain

hypoxanthine, aminopterin, & thymidine

human leukocyte antigen

hypoxanthine phosphoribosyl transferase

horseradish peroxidase

Hypervariable

Interferon

Immunoglobulin (IgG, IgM, IgD, IgE, IgA)

Interleukin

immune response

chain light chain

Lymphokin-activated killer cells (derived from NK cells stimulated with IL-2)

lipopolysaccharide (on surface of certain bacteria)

Leukotriene

membrane attack complex, part of complement system, C5b6789

muscosa-associated lymphoid tissue

major histocompatibility complex

Monocyte

Macrophage

natural killer cell

platelet activating factor

periarteriolar lymphoid sheath

Prostaglandin

polymorphonuclear (granulocyte); a.k.a.= neutrophil

severe combined immunodeficiency disease

thymus-derived lymphocyte

T cell antigen receptor

Toll like reeceptors (on macros, recognize microbial elements)

tumor necrosis factor

variable