Vocabulary List #1
activated macrophage A macrophage in a state of
enhanced metabolic activity; a "super phagocyte".
antibody (Ab) Protein molecule that is synthesized
on exposure to antigen and that combines specifically with
that antigen.
antibody dependent cellular cytotoxicity (ADCC) A
cytotoxic reaction in which killer cells recognize target
cells via specific antibodies.
antigen (Ag) A molecule which induces the
formation of antibody.
antigen presenting cell (APC) A cell which carries
antigen in a form that can stimulate lymphocytes. Macrophage
are the most common APCs.
antiserum Serum containing specific
antibodies.
antitoxin Antibodies specific for a toxin.
azurophilic granules [a.k.a. primary
granules] Granules in neutrophils which contain acid
hydrolases, myeloperoxidase, and lysozyme. (See also
specific granules.)
B cell A lymphocyte educated in the bursal
equivalent; makes antibody when stimulated.
basophil A granulocyte with deep violet or
blue-black staining granules.
buffy coat The layer of white blood cells
immediately above the red blood cells in a tube of blood
following centrifugation.
bursa of Fabricius The hindgut organ located in
the cloaca of birds that controls the ontogeny of B
cells.
cell mediated immunity (CMI) Immunity in which the
participation of lymphocytes and macrophage is
predominant.
complement (C') 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.
cortex The outer part; applies to the thymus and
lymph node.
diapedesis The emigration of cells from blood
vessels.
endogenous pyrogen A factor released by leukocytes
which produces fever.
eosinophil A granulocyte with pink to red staining
granules.
germinal center A clonal expansion of an activated
B cell seen within a secondary follicle.
granulocyte A leukocyte with large numbers of
cytoplasmic granules and a multi-lobed nucleus. The include
neutrophils, eosinophils, and basophils.
high endothelial venule (HEV) A specialized region
in the post capillary venule which contains specific ligand
receptors that are recognized by circulating lymphocytes;
once bound, the lymphocytes are transported through the
cells into the lymph node.
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histamine A vasoactive agent released by
basophils, mast cells, and platelets.
humoral immunity Immunity in which antibody plays
the significant role.
immune surveillance The concept that lymphocytes
survey the body for abnormal cells and foreign invaders and
then eliminate them.
immunity The state of resistance to an
infection.
immunoglobulin (Ig) A glycoprotein composed of H
and L chains that functions as antibody. All antibodies are
immunoglobulins; the converse may or may not be true.
interdigitating cell (IDC) A specialized cell with
long dentritic processes which functions as an APC; found
associated with T cells in the lymph node.
interferon (IFN) A heterogeneous group of low
molecular weight proteins released by virus infected cells
which protect non-infected cells.
killer (K) cell [An old
term] A natural killer cell responsible for
antibody dependent cellular cytotoxicity.
Kuppfer cell A specialized macrophage found in the
liver; acts as part of the RES.
lactoferrin An iron-containing compound that
exerts antimicrobial action by binding iron necessary for
microbial growth.
Langerhans cell A specialized antigen presenting
cell with characteristic tennis racket shaped granules;
found in the epidermis.
leukocyte A white blood cell. This general term
covers all the nucleated cells of mammalian blood.
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lymph node Secondary lymphoid organ; major
filtering organ for interstitial fluid and lymph; site of
immune response to antigens isolated and processed.
lymphocyte A mononuclear cell with a round nucleus
containing densely packed chromatin. Most have very little
cytoplasm.
lymphoid Pertaining to lymphocytes and their
ontogeny.
lymphokines Soluble products of lymphocytes that
are responsible for the multiple effects of a cellular
immune response.
lysozyme [a.k.a. muramidase] 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.
macrophage (Mf)
A phagocytic mononuclear cell derived from monocytes; serves
accessory roles in cellular immunity.
MALT Mucus associated lymphoid tissue.
medulla The inner part; applies to the thymus and
lymph node.
medullary cords Found in lymph nodes; provide
anchorage for macrophage and plasma cells.
monocyte (MO) A phagocytic mononuclear cell
derived from myeloid stem cells; found in circulating
peripheral blood.
monokines Soluble products of monocytes and
macrophage that are involved in multiple effects of the
immune response.
myeloid Pertaining to granulocytes and monocytes
and their ontogeny. Also included are megakaryocytes and
platelets.
natural antibody An antibody found in serum in the
absence of apparent antigenic stimulation.
natural killer (NK) cell A null cell capable of
killing tumor cells and virus infected cells.
neutrophil A phagocytic granulocyte with a
prominent multi-lobed nucleus; usually the first cell type
responding to injury or infection.
null cell A lymphocyte lacking any markers
specific for T cells or for B cells.
periarteriolar lymphoid sheath (PALS) Found in
spleen; organized clusters of B cells in follicles
surrounded by T cells and macrophage which occur in
association which splenic arterioles.
Peyers patch A specialized aggregate of
lymphocytes and M-cells in the gut; the major part of GALT
(gut MALT).
phagocyte A cell which eats.
phagocytosis The act of eating; refers to the
ingestion of particulate matter.
phagosome A vacuole in the cytoplasm containing
the engulfed meal.
pinocytosis The act of drinking; refers to the
ingestion of soluble matter.
plasma The fluid phase of blood containing full
range of circulating proteins, including clotting factors
and fibrin.
plasma cell An end-stage cell of B cell lineage
which makes and actively secretes antibody.
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polymorphonuclear neutrophil (PMN) A
neutrophil.
post capillary venule (PCV) A region of blood
vessels in the lymph node which may contain HEV, allowing
lymphocytes to pass through.
primary follicle An organized cluster of B cells
found in various lymphoid tissues and organs, such as lymph
node, PALS, and MALT.
pyrogen A substance which causes fever; may be
endogenous or exogenous.
red pulp 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.
respiratory burst The increase of metabolic
activity that takes place in phagocytic cells at the time of
ingestion; highly reactive microbicidal agents are produced
which are released into the phagosome.
reticuloendothelial system (RES) A mononuclear
phagocytic system located primarily in the reticular
connective tissue framework of the spleen, liver, and
lymphoid tissues.
rosettes Structures formed by several red blood
cells binding to the surface of another cell in
suspension.
secondary follicle A follicle containing a
germinal center
serum The fluid phase of blood containing all
circulating proteins except those involved in clotting.
specific granules [a.k.a. secondary
granules] Granules found in neutrophils which
contain lactoferrin and some lysozyme.
spleen Secondary lymphoid organ; filters
particulates and antigens from blood as part of the
reticuloendothelial system.
stem cells Primary bone marrow cells giving rise
to more differentiated cell types.
T cell A lymphocyte educated in the thymus;
involved in cellular immunity and in regulating all immune
responses, both humoral and cellular.
thoracic duct Final lymphatic collecting vessel
which empties into the left subclavian vein
thymus The central lymphoid organ that is located
in the thorax which controls the ontogeny of T cells.
transferrin A protein which sequesters iron,
thereby inhibiting microbial growth.
tumor necrosis factors (TNF) Products of
lymphocytes and macrophage that can exert a direct toxic
effect on neoplastic cells.
vaccination The administration of an antigen
(vaccine) to stimulate an immune response.
vaccine A suspension of living or dead organisms,
or inactivated toxins, or specific proteins used as antigen
to stimulate immunity to a pathogen.
virulence The ability of an organism to cause
disease.
white blood cells The nucleated cells found in
blood.
white pulp Part of spleen; see periarteriolar
lymphoid sheath.
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