Lymphocyte sx and fx I

Describe the general cells needed to reach the precursors of a lymphocyte.

HSC → MPP → CLP → TNKP

What is lymphopoiesis?

the production and development of lymphocytes

What kind of adaptive immunity do T-cells provide?

cell-mediated

What kind of adaptive immunity do B-cells provide?

Humoral, or antibody (fluids)

What kind of immunity do NK cells provide?

cytotoxicity without prior antigen presentation

What are the three compartments that are involved in lymphocyte production and maturation?

1. multipotential hematopoietic stem cells (HSC)

2. primary lymphoid tissues

3. secondary lymphoid tissues

What tissues are involved as primary lymphoid tissues?

bone marrow (B-cells) and thymus (T-cell)

What tissues are involved as secondary lymphoid tissues?

lymph nodes, spleen, GALT, RALT, blood

Describe the first stage of lymphocyte differentiation. Include the tissues involved, the starting cell, and the ending cells.

Bone marrow and thymus

• B = bone marrow

• T = thymus

starting cells: CLP

ending cells: immature/naive T- and B-cells

Describe the second stage of lymphocyte differentiation. Include the tissues involved, the starting cell, and the ending cells.

Lymph nodes, spleen, RALT, GALT, the periphery basically

Starting cell: immature/naive B- and T-cells

Ending cells: effector B- and T-cells

What stages of a B-cell do we see in the bone marrow (or first stage of differentiation)?

CLP, Pro-B-cell, Pre-B-cell, immature/naive B-cell

What stages of a B-cell do we see in the periphery (or second stage of differentiation)?

mature/effector B-cell

Describe the B-cell maturation stages.

1. Pro B-cell

2. Pre B-cell

3. immature B-cell

4. mature B-cell

5. plasma cell

Describe the first stage of B-cell maturation (Pre B-cell), including the main event and the CD markers present.

main event: heavy chain switching VDJ

CD: CD34, CD19, CD10

Describe the second stage of B-cell maturation (Pro B-cell), including the main event and the CD markers present.

main event: create the pre-BCR for the light chain

CD: CD19 and CD10

Describe the third stage of B-cell maturation (immature B-cell), including the main event and the CD markers present.

main event: expresses cytoplasmic IgM

CD: CD45, CD20, CD19

When a naive B-cell passes through maturation, what kinds of Ig do they express and where?

IgM and IgD on the surface

When an immunologic event occurs, what happens to the naive B-cell?

differentiates into a plasma or memory cell

isotype switching for IgG, E, or A

Where are the antibodies mainly produced in a plasma cell?

cytoplasm

Describe the general process of T-cell selection in the thymus. What is the sequence of selection that causes apoptosis or survival?

1. Positive selection - cortex

   1. select for those T-cells that have an MHC

2. Negative selection - medulla

   1. select for those T-cells that do NOT react/weakly react with self antigens

What CD marker is found on both T- and B-cells?

CD45

What CD markers are found only on B-cells?

CD20 and CD19

What CD markers are only found on T-cells?

CD3

What CD marker is only found on a T-helper cell?

CD4

What CD marker is only found on a T-killer cell?

CD8

What is the normal ratio of CD4:CD8 T-cells in a person?

2:1

What is the ratio of CD4:CD8 T-cells in a person with HIV?

1:2