LYMPHOID SYSTEM Flashcards
memorization
Primary lymphoid organs
- Bone marrow
- Thymus
Source of progenitor cells (hematopoiesis); site of B cell maturation
Bone marrow
Site of T-cell maturation:
Thymus
Note: Progenitor cells that migrate to the thymus proliferate and differentiate under the influence of thymosin
Secondary lymphoid organs:
- Lymph nodes
- Spleen
- MALT
- Cutaneous immune system (epidermis, dermis)
Secondary lymphoid organ that traps subcutaneous antigens:
Lymph nodes
Secondary lymphoid organ that is made up of red and white pulp where most lymphoid tissue is located; traps intravenous antigens:
Spleen
Which part of the lymph nodes does B-cells proliferate?
Cortex
Which part of the lymph nods does T-cells proliferate?
Paracortex
Macrophages proliferate in the _____ part of the lymph nodes
medullary/medulla
Only mature WBC that can still undergo mitosis (clonal expansion):
Lymphocyte
What part of the spleen does T-cells proliferate?
Periarterial lymphatic sheath (PALS)
What part of the spleen does B-cells proliferate?
Follicular area
What part of the spleen does macrophages proliferate?
Marginal zone
MALT stands for:
mucosa-associated lymphoid tissue
Examples of MALT:
Peyer’s patches - small intestines
Tonsils
Appendix
A type of dendritic cell that is present in the epidermis:
Langerhans cells - a special class of APC and a type of dendritic cell
Products produced by B cells:
Antibodies
Products produced by T cells:
Cytokines/lymphokines
CD markers present in B cells:
CD 19
CD 20
CD 21
CD 40
CD marker of B cell that functions as PANMAKER:
CD 19
CD marker of B cell that functions as ion channels:
CD 20
CD marker of B cell that functions as C3d receptor:
CD 21
CD marker of B cell that functions as the receptor of Epstein-Barre Virus (EBV):
CD 21
CD marker of B cell that functions as B cell isotype switching and memory formation
CD 40
CD markers present in T cells:
CD 2
CD 3
CD 4
CD 7
CD 8
Classic T-cell marker, sheep RBC receptor:
CD 2
CD marker part of the TCR complex:
CD 3
Coreceptor of MHC class II:
CD 4
Coreceptor of MHC class I:
CD 8
Identification method for B cells:
Surface immunoglobulins
Identification method for T cells:
Rosette formation with sheep RBC
A technique to separate lymphocytes from whole blood:
FICOLL-HYPAQUE CENTRIFUGATION
Ficoll-Hypaque has a specific gravity between:
1.077 - 1.114
What type of blood specimen should be utilized in Ficoll-Hypaque centrifugation?
Diluted defibrinated or heparinized blood or ACD blood
The gold standard test for the identification of lymphocytes
FLOW CYTOMETRY with light scatter
- It is coupled with the detection of surface markers (proteins) using FLUORESCENT LABELED ANTIBODIES
T cell antigens (CD markers) detected by immunofluorescence:
CD 2
CD 3
CD 4
CD 7
CD 8
B cell antigens (CD markers) detected by immunofluorescence:
CD 19
CD 20
CD 22
Cheapest manual lymphocyte identification technique:
Rosette techniques
(E-rosette assay)
(Erythrocyte-Ab-Complement Rosette)
E-rosette assay test mechanism:
Sheep cells attach to the CD2 antigen, found only on T cells
The Erythrocyte-Ab-Complement technique is a manual lymphocyte technique for the identification of:
B cells
Note: B cells have C3 receptor which is why it involves the use of antibodies and complement
T lymphocytes represent approximately ____% of the circulating lymphocytes in the peripheral blood.
80%
Surface marker of subtype Tc
CD 8
Function of subtype Tc
Destroys virally infected and tumor cells through secretion of perforins and granzymes
Surface marker of subtype Th
CD 4
Th subset that helps B cell to become a Plasma cell:
Th 2
Th subset that enhances the activity of cytotoxic cells and activates macrophages:
Th 1
Surface marker of subtype Ts:
CD 8
Function of subtype Ts:
Limit immune reactions
Surface marker of subtype Tm:
CD8 & CD4
Function of subtype Tm:
Circulate in immunosurveillance and anamnestic response
These are substances that promote cell division:
Mitogens
Enumerate T cell mitogens:
- Concanavillin A
- Phytohemagglutinin
- Pokeweed mitogen
Enumerate B cell mitogens:
- Lipopolysaccharide
- Pokeweed mitogen
Helper T (Th) cells approximately represents _____% of lymphocytes in the blood:
50-60%
Cytotoxic T (Tc) cells approximately represents ______% of lymphocytes in the blood
20-25%
Natural Killer cells approximately represents ____% of lymphocytes in the blood
~ 10%
B cells approximately represents _____% of lymphocytes in the blood
10-15%
Normal CD4 count:
500 - 1200/uL
CD4+ cells to CD8+ cells ratio:
2:1
Ratio of CD4+ cells to CD8+ cells in HIV:
1:2 to 0.5:1
CD4+ cell count in AIDS:
<200/uL
In the cortex of the thymus, immature T cells represent _____%
85%
In the medulla of the thymus, mature T cells represent ____%
15%
(Maturation of T lymphocytes in the thymus)
Expression of the classical T-cell marker; Early thymocytes lack CD4 and CD8 markers, which are important to their later function; hence, they are known as:
Double Negative (DN) thymocytes
(Maturation of T lymphocytes in the thymus)
Expression of both CD4 and CD, making them:
Double Positive (DP) thymocytes
Presence of CD 19 and CD45R; Rearrange of genes coding for heavy chains at chromosome 14:
Pro-B cell
Synthesize IgM heavy chains (u chains) confined to the cytoplasm; Light chain gene rearrangement:
Pre-B cell
kappa = chromosome ___
lambda = chromosome ___
kappa = chromosome 2
lambda = chromosome 22
Decreased cytoplasmic IgM; surface IgM present on the cell surface; CD 19, 20, and 21 positive
Naive B cell
Presence of surface IgM and IgD
Mature B cell
Antibody producing cells, derived from B cells which are exposed to various ILs and antigenic stimulation:
Plasma cell
