Medical Micro

Front 1

Overall, the immune response can be divided into what two major classifications?

Back 1

The two major classifications of the immune response are humoral and cell mediated responses.

Front 2

Define Antigen (Ag) and give the four specific examples that aid in the definition.

Back 2

An antigen is a molecule which elicits specific immune responses when introduced into an animal. More specifically, antigenic substances are:

1) Large >10,000 Da
2) Structurally Complex
3) Accessible (ie. the immune system must be able to contact the molecule)
4) Foreign (ie. not recognizable as self)

Front 3

Define Antibody (Ab)

Back 3

A glycoprotein produced in response to an antigen, that is specific for the antigen, and binds to it through noncovalent interactions.

Front 4

What is the difference between an immunoglobulin and an antibody?

Back 4

An immunoglobulin describes ANY antibody regardless of specificity and comes in different forms (IgA IgD IgE IgG IgM) that reflect their form. An antibody describes an antigen-specific immunoglobulin.

Front 5

What do "antibody kinetics" prove?

Back 5

1. The immune response is specific.
2. The immune response has memory.

Front 6

Be able to describe
this graph.

Back 6

This graph represents antibody kinetics. The x axis is a measure of time (days) and the y axis is a measure of the antibody titer (measure of the amount of antibody in the animal's serum per unit volume)

This figure represents the production of antibody in response to antigenic substances. The animal was injected with antigen A at day 0. Antigen A invokes a primary response beginning around day four and thus the antibody is mainly IgM and some IgG. After a peak titer, the response decreases rapidly. If the animal is re-injected with antigen A the production of antibody begins almost immediately and reaches a level of 1000 fold greater than seen in the primary response, and hence this is a secondary response (primarily IgG). If the animal is injected with Antigen B the body will only produce a primary response to this antigen.

Front 7

What is the clonal selection hypothesis?

Back 7

1. Animals contain numerous cells called lymphocytes.
2. Each lymphocyte is responsive to a particular antigen by virtue of a specific surface receptor molecule.

3. Upon contacting its appropriate antigen, the lymphocyte is stimulated to proliferate (clonal expansion) and differentiate.
4. The expanded clone is responsible for the secondary response (more cells to respond) while the differentiated ("effector") cells secrete antibody.

** Aims to explain antibody kinetics **

Front 8

Describe the surface components of B-lymphocytes and their corresponding function.

Back 8

1) Surface immunoglobulin = direct antigen recognition
2) Immunoglobulin Fc receptor = differentiation into antibody-producing plasma cells

3) Class II Major Histocompatabilty Complex (MHC) molecule = antigen presentation

Front 9

Describe the surface components of T-lymphocytes and their corresponding function.

Back 9

1) CD3 molecule = involved in both humoral and cell mediated responses

2) T-cell receptor = antigen recogniton

Front 10

What are the three specific types of T-lymphocytes?

Back 10

Helper T cells, Cytotoxic T cells and Suprressor T cells

Front 11

Describe the surface components unique to Helper T Cells and their function.

Back 11

CD4 molecule:
1) Recognizes antigen presented within Class II MHC

2) Promotes differentiation of B-cells and cytotoxic T-cells

3) Activates macrophages

Front 12

Describe the surface component unique to Suppressor T Cells and it's function.

Back 12

CD8 molecule:
Downregulates the activities of other cells

Front 13

Describe the surface components unique to Cytotoxic T Cells and their function.

Back 13

CD8 molecule:
1)Recognizes antigen presented within Class I MHC

2)Kills cells expressing appropriate antigen

Front 14

What are the three types of accessory cells and what are the general functions of accessory cells?

Back 14

Macrophages, dendritic cells, and polymorphonuclear cells. Phagocytosis and killing.

Front 15

Describe the surfaces component unique to Macrophages and their function.

Back 15

1) Immunoglobulin Fc receptor = Bind Fc portion of immunoglobulin (enhances phagocytosis)

2) Complement component C3b receptor = Bind complement component C3b (enhances phagocytosis)

3) Class II MHC molecule = Antigen presentation within Class II MHCSecrete IL-1 (macrokine) promoting T-cell differentiation and proliferationCan be "activated" by T-cell lymphokines

Front 16

Describe the surface component unique to dendritic cells and their function.

Back 16

Class II MHC molecule = Antigen presentation within Class II MHC

Front 17

Describe the surface components of Polymorphonuclear cells (PMNs) and their function.

Back 17

1) Immunoglobulin Fc receptor = Bind Fc portion of immunoglobulin (enhances phagocytosis)

2) Complement component C3b receptor = Bind complement component C3b (enhances phagocytosis)

Front 18

What are the two types of killer cells and what is the general function of killer cells?

Back 18

NK cells and K cells, the direct killing of cells.

Front 19

Describe an NK cell.

Back 19

The surface receptor on NK cells is unknown. They kill a variety of target cells (e.g. tumor cells, virus-infected cells, transplanted cells)

Front 20

Describe a K cell.

Back 20

The surface receptor is Immunoglobulin Fc receptor: binds Fc portion of immunoglobulinKills antibody-coated target cells (antibody-dependent cell-mediated cytotoxicity, ADCC)

Front 21

Describe mast cells.

Back 21

High affinity IgE Fc receptors are the surface receptors and they bind IgE and initiate allergic responses by release of histamine