Lymphoid cells

What are lymphocytes?

Special immune cells that directly recognize and destroy foreign material

What are the six features of the adaptive immune response?

1. specific

2. diverse

3. memorizes antigens

4. specializes defense

5. self limits through antigen elimination (backing off)

6. self tolerance with self antigens

What antibody is produced in a primary response?

IgM - less specific

What antibody is produced in a secondary response?

IgG - more specific

What is CD?

cluster of differentiation

What CD do helper T-cells have?

CD4

What CD do cytotoxic T-cells have?

CD8

What CD do NK cells have?

CD56

What is the function of B-lymphocytes (not plasma cells)?

• extracellular defense

• transformation into plasma cells

What is the function of plasma cells (effector)?

• secret antibodies

  • neutralize, opsonize (phagocytize), complement activation

Where do B-cells originate and differentiate?

Bone marrow

What are the functions of T-cells?

• fight intracellular microbes

What are the functions of helper T-cells?

• activate macrophages

• stimulate B-cells

• secrete cytokines

What are the functions of cytotoxic T-cells?

• activate macrophages via cytokines

• lyse infected cells, tumors, etc.

What are the functions of NK cells?

• kill infected cells

Why are NK cells considered apart of the innate immune response?

They do not need antigen presentation or prior exposure to a pathogen to function, they are nonspecific

Where in the lymph node do macrophages/APC reside?

cortex and paracortex

Where in the lymph node do B-cells reside?

Cortex

Where in the lymph node do T-cells reside?

Paracortex

Where in the lymph node do plasma cells reside?

medulla

List the steps of T-cell activation.

1. APC phagocytoses, digests, and presents a peptide to a naive T-cell within the lymph node.

2. T-cell recognizes the peptide and activates

3. proliferation through clonal expansion

4. effector T-cell production depending on MHC class

   1. class I = CD8 cytotoxic

   2. class II = CD4 helper

List the steps of B-cell activation.

1. IgM and IgD on a naive B-cell bind to an antigen.

2. Helper T-cells bind to the naive B-cell with the SAME antigen, activation occurs

3. Naive B cell begins differentiation through heavy chain isotype switching

4. Production of plasma cells or memory cells

What is a monoclonal antibody?

An antibody that binds to one epitope

Why are Mabs useful in diagnostic testing?

Define MHC antigens, tumor antigens, viral and fungal antigens

What are some congenital T-cell disorders?

thymic hypoplasia (DiGeorge)

What are some congenital B-cell disorders?

X-linked agammaglobulinemia

What are some acquired T-cell disorders?

Lupus, AIDS, Hodgkins, and chronic leukemia

What are some acquired B-cell disorders?

Multiple myeloma