Key Terms
active immunity
immunity developed from an individual’s own immune system
acute inflammation
inflammation occurring for a limited time period; rapidly developing
adaptive immune response
relatively slow but very specific and effective immune response controlled by lymphocytes
afferent lymphatic vessels
lead into a lymph node
antibody
antigen-specific protein secreted by plasma cells; immunoglobulin
antigen
molecule recognized by the receptors of B and T lymphocytes
antigen presentation
binding of processed antigen to the protein-binding cleft of a major histocompatibility complex molecule
antigen processing
internalization and digestion of antigen in an antigen-presenting cell
antigen receptor
two-chain receptor by which lymphocytes recognize antigen
antigenic determinant
(also, epitope) one of the chemical groups recognized by a single type of lymphocyte antigen receptor
B cells
lymphocytes that act by differentiating into an antibody-secreting plasma cell
barrier defenses
antipathogen defenses deriving from a barrier that physically prevents pathogens from entering the body to establish an infection
bone marrow
tissue found inside bones; the site of all blood cell differentiation and maturation of B lymphocytes
bronchus-associated lymphoid tissue (BALT)
lymphoid nodule associated with the respiratory tract
central tolerance
B cell tolerance induced in immature B cells of the bone marrow
chemokine
soluble, long-range, cell-to-cell communication molecule
chronic inflammation
inflammation occurring for long periods of time
chyle
lipid-rich lymph inside the lymphatic capillaries of the small intestine
cisterna chyli
bag-like vessel that forms the beginning of the thoracic duct
class switching
ability of B cells to change the class of antibody they produce without altering the specificity for antigen
clonal anergy
process whereby B cells that react to soluble antigens in bone marrow are made nonfunctional
clonal deletion
removal of self-reactive B cells by inducing apoptosis
clonal expansion
growth of a clone of selected lymphocytes
clonal selection
stimulating growth of lymphocytes that have specific receptors
clone
group of lymphocytes sharing the same antigen receptor
complement
enzymatic cascade of constitutive blood proteins that have antipathogen effects, including the direct killing of bacteria
constant region domain
part of a lymphocyte antigen receptor that does not vary much between different receptor types
cytokine
soluble, short-range, cell-to-cell communication molecule
cytotoxic T cells (Tc)
T lymphocytes with the ability to induce apoptosis in target cells
delayed hypersensitivity
(type IV) T cell-mediated immune response against pathogens infiltrating interstitial tissues, causing cellular infiltrate
early induced immune response
includes antimicrobial proteins stimulated during the first several days of an infection
effector T cells
immune cells with a direct, adverse effect on a pathogen
efferent lymphatic vessels
lead ou