Glossary Ch 4 Flashcards
Adaptive immunity
A type of resistance that is characterized by specificity for each individual pathogen, or microbial agent, and the ability to remember a prior exposure, which results in an increased response to that pathogen upon repeated exposure
Allelic exclusion
The selection of an allele on one chromosome only
Antigen-dependent phase
The final phase of B-cell development, which occurs when a B cell is stimulated by an antigen and undergoes transformation to a blast stage, resulting in the formation of memory cells and antibody-secreting plasma sells
Antigen-independent phase
The first phase of B-cell development in the bone marrow, which results in mature B cells that have not yet been exposed to antigen
Cell flow cytometry
An automated system for identifying cells based on the scattering of light as cells flow single file through a laser beam
Cell-mediated immunity
A type of immunity in which T cells produce cytokines that help to regulate both the innate and adaptive immune response
Central tolerance
Destruction of potentially self-reactive T and B cells as they mature in either the thymus or the bone marrow
Chemokines
A large family of homologous cytokines that promote migration of WBCs through chemotaxis
Clonal deletion
The process of elimination of clones of lymphocytes that would be capable of an autoimmune disease
Cytotoxic cells T cells
T cells that bear the CD8 marker; They kill virus-infected cells and tumor cells by triggering apoptosis
Double-negative (DN) tymocytes
Stage in the development of T cells when neither CD4 nor CD8 is expressed
Double-positive (DP) tymocytes
Stage in the development of T cells when when both CD4 and CD 8 antigens are expressed
Humoral immunity
Protection from disease resulting from substances in the serum (e.g., antibodies)
Immature B cells
A phase in the growth of B cells characterized by the appearance of complete IgM antibody molecules on the cells surface
MHC restriction
The selection of thymocytes that will only interact with the MHC antigens found on the cells
Negative selection
The process by which T cells that can respond to self-antigen are destroyed in the thymus
Plasma cell
A differentiated B cell that actively secretes antibody
Positive selection
The process of selecting immature T lymphocytes for survival on the basis of expression of high levels of CD3 and the ability to respond to self-MHC antigens
Pre-B cells
The statge of development of a B cell where the heavy-chain part of the molecule is present
Pro-B cells
A stage in B-cell development in which rearrangement of the genes that code for the heavy-chain region of an antibody molecule occur
Surrogate light chain
Two short polypeptide chains noncovalently associated with each other that appear before actual light chains are formed by a developing B cells
T-dependent antigens
An antigen that requires T-cell help in order for B cells to respond
T-helper (Th) cells
Lymphocytes that express the CD4 antigen; their function is to provide help to B cells in recognizing foreign antigen and producing antibody to it
T-independent antigens
An antigen that is able to elecit antibody formation in the absence of T cells
