Lymphocyte maturation and functions

What are the three lymphocyte maturation stages?

1. lymphoblast

2. prolymphocyte

3. lymphocyte (small and large)

Describe the general characteristics of a lymphoblast (size, chromatin, cytoplasm, N:C ratio).

size: 16-24 um

chromatin: fine and grainy looking, some nucleoli

cytoplasm: deeply basophilic

N:C ratio: high, very round oval nucleus

Describe the general characteristics of a prolymphocyte (size, chromatin, cytoplasm, N:C ratio).

size: 18-28 um

chromatin: condensing, some blocks

cytoplasm: deeply basophilic, but more abundant

N:C ratio: moderate, nucleus has shrunk

Describe the general characteristics of a lymphocyte (size, chromatin, cytoplasm, N:C ratio).

size: 8-12 (small) or 12-15 (large) um

chromatin: condensing, more blocky

cytoplasm: pale blue

N:C ratio: moderate

Describe the shaping and N:C ratio of a small lymphocyte.

very round, including nucleus, almost the same size as an RBC

N:C ratio is high

Describe the shaping and N:C ratio of a large lymphocyte.

irregular borders and shape with nucleus 

chromatin is a little lighter than a small lymph

N:C ratio is moderate

What characteristic may differentiate between a small and large lymphocyte besides size?

presence of purple granules

Describe the general characteristics of a plasma cell (size, chromatin, cytoplasm, nucleus shape).

size: 14-20 um

chromatin: in a wheel spoke shape

cytoplasm: deep blue except for the golgi that hangs out along one side of the nucleus

nucleus shape: eccentrically placed, oval, one flat-ish side

What are five CD markers on the surface of a B-cell?

CD45, 20, 19, 32, 21

What are the functions of a B-cell?

produce antibodies as plasma cells

retain memory

have IgM or IgD on surface of cells 

produce IgA as 1st line of defense in mucosal surfaces 

What are the functions of T-cells?

protect against intracellular pathogens

help activate B-cells and macrophages

APC interactions

IL-2 and IFN-gamma secretion from T-helper cells

form rosettes when interacting with sheep RBCs

What cells typically constitute null lymphocytes?

NK cells or lymphocytes that have lost their CD markers

Which cell population secretes IL-1? What is the function of IL-1?

macrophages and monocytes

fx: to activate CD4 T-cells and raise body temperature through CNS signaling

Which cell population secretes IL-2? What is the function of IL-2?

T-helper cells

fx: expansion and activation of other lymphocytes and NK cells 

What are some other lymphokines that T-helper cells secrete?

BCGF, BCDF, and IFN-gamma

What is the function of IFN-gamma?

to inhibit viral replication, inhibit TH2 cells, activate macrophages

What are the functions of BCGF and BCDF?

BCGF - growth factor, so it helps stimulate growth of B-cells

BCDF - differentiation factor, so it helps differentiate immature B-cells to effector cells