Ch 18 Immune Disorders

Question 1

Hypersensitivity

Answer 1

also known as allergy, this is when the immune system reacts in an exaggerated or inappropriate way to a foreign substance

Question 2

4 types of Hypersensitivity

Answer 2

(Type I) Immediate
(Type II) Cytotoxic
(Type III) Immune Complex
(Type IV) Delayed (cell mediated)

Question 3

Immediate Hypersensitivity (Type I)

Answer 3

also known as anaphylaxis; results from a prior exposure to a foreign substance called an allergen, which is an antigen that provokes a hypersensitivity response. Involves antibodies

Question 4

Cytotoxic Hypersensitivity (Type II)

Answer 4

elicited by antigens in cells, especially red blood cells, that the immune system recognizes as foreign. This reaction occurs when a patient receives the wrong blood type during a transfusion. Involves antibodies

Question 5

Immune Complex Hypersensitivity (Type III)

Answer 5

elicited by antigens in vaccines, on microorganisms, or on a person’s own cells. Large antigen-antibody complexes form, precipitate on blood vessel walls, and cause tissue injury within hours. Involves antibodies

Question 6

Delayed Hypersensitivity (Type IV)

Answer 6

triggered by exposure to foreign substances from the environment (like poison ivy), infectious disease agents, transplanted tissues, and the body’s own tissues and cells. Delayed hypersensitivity T cells react with the foreign cells or substances causing in some cases extensive tissue destruction. Cell mediated and does not involve antibodies

Question 7

Primary Immunodeficiencies

Answer 7

genetic or developmental defects in which the person lacks T cells or B cells or has defective ones.

Question 8

Secondary Immunodeficiencies

Answer 8

result from damage to T cells or B cells after they have developed normally

Question 9

Autoimmunization

Answer 9

the process by which hypersensitivity to self develops. This results in the production of autoantibodies

Question 10

Reasons for autoantibody production

Answer 10

(1) genetic factors
(2) antigenic mimicry
(3) Failure of clonal deletion
(4) mutations
(5) Viral components inserted into host cell membranes act as antigens
(6) damage to the sympathetic nervous system

Question 11

Antigenic mimicry

Answer 11

antigens of tissue resemble antigens of some pathogens, causing the body to attack them

Question 12

Failure of clonal deletion

Answer 12

failure to delete TH cells that recognize self antigens

Question 13

Examples of Autoimmune Disorders

Answer 13

Myasthenia Gravis, Rheumatoid Arthritis, & Systemic Lupus Erythematosus

Question 14

Autograft

Answer 14

grafting of tissue from one part of the body to another

Question 15

Isograft

Answer 15

a graft between genetically identical individuals

Question 16

allograft

Answer 16

a graft between two people who are not genetically identical

Question 17

xenograft

Answer 17

a transplant between individuals of different animal species

Question 18

major histocompatability complex (MHC)

Answer 18

Genes that produce a set of self antigens called histocompatability antigens

Question 19

human leukocyte antigens (HLAs)

Answer 19

The MHC molecules that are found on human cells.

Question 20

transplant rejection

Answer 20

when transplants at first appear healthy, but within a few weeks become inflamed and fall off. Caused by rejection by the body’s immune sytstem

Question 21

HLA-DR

Answer 21

antigens that are known to generate the strongest rejection reactions

Question 22

Graft-versus-host (GVH) disease`

Answer 22

when the transplanted tissue contains immunocompetent T cells that launch a cell-mediated responce against the recepient’s tissues

Question 23

Difference between transplant rejection and GVH

Answer 23

• Transplant rejection the host rejects the transplant

- GVH the transplant rejects the host

Question 24

Drug Reactions

Answer 24

most drug molecules are too small to act as allergens. However, if a drug combines with a protein in our body, it can act as a hapten and induce hypersensitivity. All 4 types of hypersensitivity can be triggered by drug reactions

Question 25

Why does HIV interfere with the proper function of both the humoral and cell-mediated portions of the immune response?

Answer 25

because HIV almost exclusively attacks the lymph nodes, which are essential to all immune function.

Question 26

sererology

Answer 26

the scientific study of plasma serum and other bodily fluids

Question 27

Precipitin Test

Answer 27

used to detect antibodies or antigens. Based on a precipitation reaction in which antibodies called precipitins react with antigens, diffuse towards eachother, and form a visible precipitate

Question 28

Precipitin Test: Agar vs Liquid

Answer 28

The precipitn test can be performed in both liquid and in agar, however the results that you are looking for are the same in both. and that is the presence of a precipitin band or ring which signals the presence of antibodies and antigens.

Question 29

Agglutination

Answer 29

the clumping together of cells

Question 30

antibody titer

Answer 30

the quantity of antibodies

Question 31

Complement Fixation Test

Answer 31

A multistep procedure that begins with the inactivation of complement from a patient's serum by heating. The serum is then diluted, and know quantities of known non human complement and test antigen are added. The antigen is specific to the antibody that is being tested for. The mixture is incubated to allow the antigen to react with any antibody present. Next, an indicator system typically consisting of sheep red blood cells and antibody against those cells are added. If the antibody to the test antigen was present in the patient’s serum, the antigen-antibody reaction will have fixed (combined with) the complement. Hence the blood cells will not be lysed, and the test will be positive, forming a red button of undamaged cells

Question 32

If it was suspected that a patient had a particular microorganism in their bloodstream, what would one need to detect this organism in a sample of their blood if you want to use fluorescence microscopy?

Answer 32

To detect directly the presence of a specific antigen in a tissue a solution of fluorescein-tagged antibody to that antigen is prepared, added to cells or to a thin section of tissue, incubated, and then washed. Any dye-tagged antibody that has complexed with antigen in tissue will fluoresce when viewed by fluorescence microscopy.

Question 33

Enzyme-linked immunosorbent assay (ELISA)

Answer 33

a modification of RIA in which the anti-antibody, instead of being radioactive, has an enzyme tag attatched to it. TO measure an antibody in a test specimen by ELISA, a known antigen is placed in plastic well plates. Some antigen molecules attach to the plastic. The antibody being measured is added and allowed to bind with the antigen. After the antibody being measured has reacted with the antigen, the anti-antibody–enzyme complex is added. Finally, a substrate that the enzyme converts to a colored product is applied. The amount of colored product is proportional to the concentration of the antibody.

Question 34

Desensitization

Answer 34

denatured allergen is injected subcutaneously which may induce a state of tolerance, preventing the activiation of those B cells that mature into IgE secreting plasma cells. By receiving gradually increased doses of this injection, one may produce IgG antibodies called blocking antibodies, against the allergen. The number of suppressor T cells sensitized to the allergen also increase significantly during desensitization .

Question 35

Blocking antibodies

Answer 35

these antibodies bind to the allergen before it has a chance to react with IgE, so mast cells do not release mediators.