Exam 4: Ch 20 Flashcards
primary lymphoid organs
and
secondary lymphoid organs
primary: thalamus and bone marrow
secondary: (the rest) tonsil, lymph nodes, spleen, appendix, lymph vessels, and Peyer’s patches of intestine
B cells and T cells are lymphocytes produced where?
bone marrow
lymphocyte
Type of leukocyte possessing specific receptors for recognizing antigen or MHC I molecules presented on other cells; includes NK cells, B cells, and T cells
antigen
Any component that can be specifically bound by an immune receptor, namely a T-cell receptor (TCR) or an immunoglobulin (Ig)
B cell
Lymphocyte of the adaptive immune system expressing immunoglobulin B-cell receptors (BCRs) on their surface; give rise to antibody-secreting plasma cells; also called B lymphocyte
T cell
Lymphocyte of the adaptive immune system that matures in the thymus and expresses surface T-cell receptors (TCRs); also called T lymphocyte
epitope
Single antigenic site on a molecule that is recognized and bound by an immune receptor, such as an immunoglobulin (BCR or antibody) or TCR. the smallest part of an antigen
primary immune response
Response of the adaptive system that occurs with first exposure to an antigen, involving activation of naïve T cells and B cells, in the absence of immunological memory
anamnestic (secondary) response
Immune response that originates from the stimulation of memory cells and is characterized by a faster and more vigorous adaptive immune response upon repeated exposure to antigen; see also memory response
antigen-presenting cell (APC)
The only cells capable of activating T cells.
Cell capable of processing and presenting antigen in association with MHC molecules; includes dendritic cells, macrophages, and B cells.
dendritic cell
Migrating antigen-presenting cell found in most tissues of the body, characterized by extensive cytoplasmic projections
MHC I binds with
CD8
MHC II binds with
CD4
CD4+ T cell
T lymphocyte expressing the surface molecule CD4
CD8+ T cell
T lymphocyte expressing the surface molecule CD8
Activation of a T cell results in?
production of interleukin-2 (IL-2), which induces clonal expansion to produce a population of genetically identical memory T cells and effector cells, all possessing the same antigen-specific TCR.
T helper Cell (TH cell)
Effector CD4+ T cell that secretes cytokines involved in directing immune responses
Cytotoxic T Cell (TC Cell)
Effector CD8+ T cell that induces apoptosis in target cells through MHC I:antigen binding followed by the release of perforin and granzyme
exogenous antigen
Peptide antigen that enters the endocytic pathway from outside the cell and is presented on MHC II molecules
endogenous antigen
Peptide antigen that originates from the cytoplasm of a cell and is presented on MHC I molecules
cross-presentation
Pathway in antigen-presenting cells that shuttles proteins from the endocytic pathway into the endogenous pathway to allow for both CD4+ and CD8+ T-cell activation
humoral immune response
Adaptive immune response dominated by TH2 cells and characterized by production of large amounts of antibody in response to extracellular pathogens or toxins
TH1 Cell
Cell belonging to a subset of T helper (TH) cells that secretes cytokines, such as IL-2, IFN-γ, and TNF-β, to produce a cell-mediated immune response
cell-mediated immune response
Immune response dominated by TH1 cells, TC cells, increased activation of macrophages, and inflammation in response to the presence of intracellular pathogens