Transcript No Slide Title

Lymphocytes and
Lymphoid Tissues
Basic Pathway
Figure 2-3
Lymphocytes and Lymphoid
Tissues
• Primary lymphoid tissues
(thymus and bone marrow),
• Secondary lymphoid tissues
(lymph nodes, Peyer’s patches, and spleen)
• Tertiary lymphoid tissues
(skin and mucosal lamina propria)
Components of the Immune System
I. Bone Marrow - Hematopoietic Stem Cells
• Myeloid progenitor
– neutrophils
– basophils
– eosinophils
-macrophage
- mast cells
• Common lymphoid progenitor
– T-lymphocytes
– B-lymphocytes
Hematopoiesis
Hematopoiesis is driven by
cytokines:
 stem cell factor;
 IL-3;
 GM-CSF; G-CSF; M-CSF;
 IL-7
 IL-11
Hematopoiesis
• Erythrocyte-stimulated
•
•
•
by EPO
(Amgen) EPO = erythropoietin
Megakaryocyte/Platelets-stimulated
by IL-11
Granulocyte/Monocyte-stimulated
by GM-CSF, G-CSF, and M-CSF
Lymphocyte -stimulated by IL-7
Cytokines & growth factors
IL-7
Lymphoid
System
MALT = mucosal associated lymphoid tissue
Lymphocyte Maturation
Stem Cell
Naïve or virgin lymphocytes migrate to
secondary lymphoid organs
(short lived)
Activation
Memory-Effector cells
Key Concept
Thymus
T-Lymphocyte Maturation
Thymus
 The thymus is an organ strictly
dedicated to the selection and
differentiation of T lymphocytes.
 The T cell precursor cells originate in
the bone marrow and then go through a
series of developmental steps resulting
in the production of a population of
mature, antigen-sensitive T-cells.
Thymus
 The thymus is made up of a cortex
and a medulla.
 The cortex consists of densely
packed immature thymocytes,
macrophages, and dendritic cells
supported by a thymus stroma largely
made up of epithelial cells.
 The medulla contains mainly mature
thymocytes and macrophages (and a
stroma), and the cells are much less
dense.
Thymus
Cortex
Medulla
Neonatal
Thymus
Younger
Thymus
Cortex
Younger
Thymus
Medulla
Hassall’s corpuscles
are tightly packed
epithelial cells from
degenerating cells.
Adult
Thymus
atrophies
at puberty
Clonal Selection-Thymus
• Each lymphocyte bears a single
antigen specificity
• The a high affinity interaction
between the antigen and the T-cell
leads to lymphocyte activation.
• Effector cells derived from the
activated lymphocyte will bear
identical receptors as the parent cell.
• Lymphocyte bearing binding receptors
for self-antigens are normally
deleted.
Thymic
processing
of
T-cells
Thymic
processing
of
T-cells
See notes
T-Lymphocytes
• T-cells
– Cellular mediated immunity
– Antigen-presentation
– Major histocompatibility Complex
(MHC)
– T-cell Subsets
– CD4 (Th1 and Th2)
– CD8
B-lymphocytes
B-Lymphocytes
B-Cells - Humoral Immunity
• B-cell lineage synthesize immunoglobulins
Memory
virgin
Plasma
B-Cells - Humoral Immunity
• Secretion of certain lymphokines
–
–
–
–
IL-6
IL-6, 4,11
IL-6, 2,5, TGF-b
IL-6, 4
IgM
IgG
IgA
IgE
• Present Antigen to T-cells
T-Lymphocytes
B-cell
APC
T-helper
T-cytotoxic
Lymphocyte
Circulation
Thoracic Duct
Figure 2-1
Figure 2-1
Lymph Node
Lymph Node
Lymph Node
Spleen
Complete
Pathway
KNOW
Question
1._____After birth, human Blymphocyte differentiation takes
place in the
A. Bone marrow
B. Liver
C. Gut-associated lymphoid tissue
D. Spleen germinal center
E. Peyer's patches
Question
2._____ The characteristic of the innate
immune response is:
A. Has memory
B. Occurs in minutes to hours
C. Takes about 5 days to be effective
D. Requires antigen presentation by antigen
presenting cells
E. Involves the formation of immunoglobulins
Question
3._____ The acute-phase (formation of
acute phase proteins) response:
A. Is stimulated by interleukin-1b,
interleukin-6, tumor necrosis factor-a,
interferon-g
B. Is a recent marker of coronary heart
disease
C. Facilitates the phagocytosis of
bacteria
D. Is an immunological marker of chronic
inflammatory disease
E. All of the above
Question
4._____Chemotaxis means:
A. Phagocytosis of bacteria
B. Clonal elimination of B-cells
C. Induction of migration of an immune
cell
D. Adhesion of immune cells to the
vascular endothelial cells
E. Isotype switch from IgM to IgE
Question
5._____ Interferons were first
characterized by their:
A. Enhancement of B cell proliferation
B. Antiviral activities
C. Cytotoxicity of transformed cells
D. Activation factor for eosinophils
E. Stimulation of growth of precursors of
all the hemopoietic lineage
Question
6.____A plasma cell secretes:
A. Antibody of identical specificity to
that on the surface of the parent Bcell.
B. Antibody of two antigen specificities.
C. The antigen it recognizes.
D. Antibodies that recognize numerous
antigens
E. Lysozyme.
Question
7._____ Secondary lymphoid tissues
include:
A.
B.
C.
D.
E.
Bone marrow and thymus
Skin, mucosal surfaces
Neutrophils and eosinophils
Complement
Thymus, lymph nodes, spleen,
MALT, and BALT tissues
Question
8.____CD8 is a marker of:
A. B-cells
B. Helper T-cells
C. Cytotoxic T-cells
D. An activated macrophage
E. A polymorph precursor
Question
9._____Specific antibodies are readily
detectable in serum following primary
contact with antigen after:
A. After 10 minutes.
B. Within 1 hour.
C. By 5—7 days.
D. After 3—5 weeks.
E. Only detectable after a second contact
with antigen.
Question
10._____Which of the following is a
well-known effect of interleukin-8?
A. Attraction and activation of
neutrophils
B. Induction of B-cell proliferation
C. Induction of the switch from IgM to
IgG synthesis
D. Induction of B-cell differentiation
E. Suppression of interleukin release by
helper T cells
Monday’s class
• There will be no class due to the
MLK holiday.