Untitled - D Ank Unlimited

thymus-dependent (TD) areas 702 thymus-dependent lymphocyte
Thymic
cortex
Thymic
medulla
Peripheral
blood, T cell
compartment
T cells must be in the context of major histocompatibility
complex (MHC) class II molecules. Thymus-dependent
antigens include proteins, polypeptides, hapten–carrier
complexes, erythrocytes, and many other antigens that
have diverse epitopes. T-dependent antigens contain some
CD3 CD2
CD6
CD5 CD8
CD2
CD1A CD2
CD8 CD4
CD8 CD2
CD3 CD4
Early
thymocyte
Common
thymocyte
CD5 CD2
CD4
CD6 CD3
Mature
thymocyte
CD3 CD2 CD5 CD4 Helper
Suppressor- CD8
CD6 CD3
T cell
Cytotoxic CD5 CD6
T cell
CD2 CD2
CD3 CD4 CD5
CD4 Helper
inducer
Suppressor- CD6
CD3 CD6
Inducer T cell CD2 CD5
T cell
CD29
CD45RA
T cell maturation showing the addition of CD (cluster of differentiation) markers and position of T cell (in thymus or periphery) when marker is added.
Structural properties
Chemistry
Antibody classinduced
Immunological
memory
response
Present in most
pathogenic
microbes
Thymus-dependent (TD) antigen.
T Celldependent
antigen
Complex
Proteins; proteinnucleoprotein
conjugates;
glycoproteins;
lipoproteins
IgG, IgM, IgA
(+IgD and IgE)
Yes
Yes
Simple
Polysaccharide of
pneumococcus;
dextran polyvinyl
pyrolidone;
bacterial lipopolysaccharide
IgM
No
No
Thymus-dependent (TD) antigen.
T Cellindependent
antigen
epitopes that T cells recognize and others that B cells
identify. T cells produce cytokines and cell surface molecules
that induce B cell growth and differentiation into
antibody-secreting cells. Humoral immune responses to
T-dependent antigens are associated with isotype switching,
affinity maturation, and memory. The response to
thymus-dependent antigens shows only minor heavy-chain
isotype switching or affinity maturation, both of which
require helper T cell signals.
thymus-dependent (TD) areas
Regions of peripheral lymphoid tissues occupied by T
lymphocytes: the paracortical areas of lymph nodes, the
zones between nodules and Peyer’s patches, and the centers
of splenic malpighian corpuscles. These regions contain
small lymphocytes derived from circulating cells that reach
these areas by passage through high endothelial venules.
Proof that these anatomical sites are thymus-dependent is
the lack of lymphocytes in these areas exhibited by animals
thymectomized as neonates. Likewise, humans and animals
with thymic hypoplasia or congenital aplasia of the thymus
reveal no T cells in these areas.
thymus-dependent (TD) cells
Lymphoid cells that mature only under the influence of
the thymus.
thymus-dependent lymphocyte
Refer to thymus-dependent (TD) cells.
Thymus-independent (TI) antigen.