6th Page Flashcards
What are the 3 main populations of lymphocytes in the adaptive immune system?
(difficult to distinguish visually)
T cells (61%-80%)
B cells (10%-20%)
Nk cells (10%-15%)
Where do lymphocytes arise from?
Hematopoietic Stem Cells (HSC)
Where do lymphocytes differentiate?
In the primary lymphoid organs: Bone Marrow (BM) and Thymus
What is used to identify lymphocyte subpopulations?
Proteins or antigens on cell surfaces
What does CDS stand for?
Cluster of Differentiation
It is used to identify and characterize cell surface molecules on leukocytes
CDs (Cluster of differentiation)
What are the functions of T cells?
- Helper
- Cytolytic/ Cytotoxic
- Regulatory
produce cytokines
stimulate B cells to produce Ab (T HELPER CELL)
assist in killing tumor cells or infected target cells (Cytolytic/ Cytotoxic)
What is the function of B cells?
Develop into plasma cells and produce antibodies (Ab)
Where does maturation and differentiation of B cells occur?
Bone Marrow
Where do production T cells occur?
Bone Marrow
Where do production B cells occur?
Bone Marrow
Where does maturation and differentiation of T cells occur?
Thymus
What are the surface markers for T cells?
CD2, CD3, CD4, CD8, MHC Class I and II
What is the role of cytolytic T cells?
Assist in killing tumor cells or infected target cells
Immunity of T cells
Cell mediated
Immunity of B cells
Humoral mediated
Location in Lymph nodes in T cells
Paracortical region
Location in Lymph nodes in B cells
Cortical region
Identification in T cells
Rosette formation with SRBC
What is the location of T cells in lymph nodes?
Paracortical Region.
What are some mitogens for T cells?
Concanavalin A, PHA, PWM
Mitogenic activation of B cells
Concanavalin A, PHA, PWM, LPS, Protein A PMA
What are some mitogens for B cells?
LPS, Protein A, PMA.
What are lymphocytes?
Lymphocytes arise from pluripotential hematopoietic stem cells.
Where do lymphocytes differentiate?
in primary lymphoid organs.
What are the primary lymphoid organs?
bone marrow (BM) and thymus.
considered as the largest tissue if the body, with a total weight of 1300-1500 g in adult
Bone marrow
Where do immature and mature T cells reside in the thymus?
Not fully mature T cells reside in the cortex
Mature T cells reside in the medulla before being released.
The bone marrow functions as the center for:
antigen-independent lymphopoieses
Bone marrow
site where most blood cells mature including B cells and NK cells
Thymus
site where T cells mature and develop their identifying characteristics
What are secondary lymphoid organs?
Where main contact with foreign antigens takes place.
What is the spleen?
The largest secondary lymphoid organ
filters blood and is responsive to blood-borne pathogens.
What are the two types of pulp in the spleen?
Red pulp and white pulp.
What does red pulp do?
Makes up more than one half of the total volume
Destroys RBCs.
What does white pulp contain?
Contains lymphoid tissue.
What are the regions of Spleen?
PALS, primary follicles, and marginal zone
What is PALS?
Periarteriolar lymphoid sheaths; contains mainly T cells.
What do primary follicles contain?
naive B cells.
What does the marginal zone contain?
Contains dendritic cells.
What are lymph nodes?
Filter tissue
Protects the body from antigens that come from skin or internal surfaces
Lymph nodes
Transported via the lymphatic vessels
How do lymph nodes respond to antigens?
Introduced distally and routed to them by afferent lymphatics.
What are the layers of lymph nodes?
Cortex, paracortex, and medulla.
What does the cortex of lymph nodes contain?
Contains macrophages, follicular dendritic cells, naïve or resting B cells (in primary follicle), proliferating B cells, and plasma cells (in 2ndary follicles or germinal centers)
What does the paracortex contain?
Contains mainly T cells.
What does the medulla contain?
T cells
B cells
plasma cells
macrophages
What is MALT?
Mucosa-associated lymphoid tissue, includes appendix, tonsils, and Peyer’s patches.
Other secondary lymphoid organs aside from spleen and lymph nodes?
MALT
Appendix
Tonsils
Peyer’s patches.
What are BALT and GALT?
Bronchus-associated lymphoid tissue
Gut-associated lymphoid tissue.
Intracellular Antigens
MHC I
What does the small intestine (ileum) contain?
Lymphatic nodules.
Extracellular Antigens
MHC II
Mitogen examples
PHA - Phytohemagglutinin
PWM- Pokeweed Mitogen
PMA - Phorbol Myristate Acetate