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
class-switching
Genetic process in activated B cells that results in production of one of the classes of IgA, IgG, or IgE immunoglobulin from the initial production of class IgM
T-independent antigen
Antigen that can stimulate B cells to proliferate into antibody-secreting plasma cells without requiring B-cell interaction with T cells; possesses highly repetitive structures with the ability to crosslink several BCRs on a B cell
What is the effector function of B-cells versus that of T-cells?
B-cells produce antibodies and T cells target and destroy cells
MHC I molecules versus MHC II molecules: endogenous versus exogenous antigen presentation
exogenous antigens are peptide antigens that enter the endocytic pathway from outside the cell and are presented on MHC II molecules that bind to CD4.
endogenous antigens are peptide antigens that originate from the cytoplasm of a cell and are presented on MHC I molecules and bind to CD8.
The functions of the different antibody classes: Which is primarily found in secretions, which is
involved in allergies and parasitic infections, which is the major class found in serum and
capable of crossing the placenta, which is the first class made during the primary immune
response?
IgA is primarily found in secretions. Functions to the agglutination of antigen; binding to phagocyte FC receptors for Phagocytosis
IgE is involved in allergies and parasitic infections. Functions to the Crosslinking with antigen induces degranulation in mast cells, eosinophils, basophils
IgG is the major class found in serum and
capable of crossing the placenta. Functions in Complement activation; opsonization for
phagocytosis; toxin neutralization; ADCC
killing by NK cells
IgM is the first class made during the primary immune response. Functions in Complement activation; agglutination of
antigen for phagocytosis
Know the difference between an antigen and its epitopes
epitopes are the actual fragments or extensions of an antigen that can interact with immune receptors.
What are the differences between CD4 versus CD8 T-cells?
CD4 cells are helper T cells and CD8 are cytotoxic cells that directly attack foreign microbes.
Which immune cells are antigen presenting cells?
macrophages, dendritic cells, and B cells.
