9- Immunology IV, V, VI

Question 1

What is humoral immunity?

Answer 1

Soluble antibodies in immune serum are an expression of humoral immunity which has the characteristic that it effects can be transferred to unimmunized animals by the transfer of serum obtained from immune animals

Question 2

What are the 4 attributes of the immune system?

Answer 2

1. The immune system has distance arms it employs to fight foreign invaders: humoral and cell-mediated immunity
2. Universality and specificity: implications for diversity of antibodys
3. Self-nonself discrimination
4. Immune class regulation

Question 3

How did Metchnikoff discover phagocytes?

Answer 3

He inserted a thorn from a tree into the transparent larva of a starfish and when examining the injured larva the next morning, he found the thorn to be surrounded by cells that have the ability to take up and digest foreign matter called phagocytes

Question 4

What is cell mediated immunity?

What is a tuberculosis example?

Answer 4

Immunization cannot be transferred from resistant to normal animals by transfer of serum, but requires transfer of cells
Cells are essential elements required for resistance
Example: the pathogen responsible for tuberculosis does not have antibodies that contain an infection by this pathogen, but cell-mediated immunity is able to

Question 5

What is immediate-type hypersensitivity and delayed type hypersensitivity?

Answer 5

Immediate-type- immunization with antigen leads to state where acute inflammation can be elicited following injection of antigen in skin
Delayed type- a delayed reaction that reached a maximum intensity between 24 and 72 hours after application of antigen
This cannot be transferred through serum, only through transfer of cells from sensitized to unsensitized individual
HYPERSENSITIVITY IS A CELL MEDIATED IMMUNITY

Question 6

What is self-nonself discrimination?

Answer 6

The ability to respond to foreign but not self molecules and self cells
The ability of the immune system to attack foreign cells but not its own cells

Question 7

What are the 4 major classes of antibody?

Answer 7

IgE
IgM
IgG
IgA
Several distinct classes of antibody

Question 8

What are allergies in the immune system?

Answer 8

Occur due to induction of IgE antibodies usually to antigens found in environment
Antigens that induce allergic responses are referred to as allergens
Once exposed to these antigens, symptoms of acute inflammation occur at sites of antigen deposition

Question 9

What is autoimmunity in the immune system?

Answer 9

Induction of autoimmunity to self molecules, cells, or organs
Diseases where immune system attacks cells or organs of individual immune system belongs
Type I diabetes
Myasthenia gravis
Rheumatic heart disease

Question 10

What are infectious diseases in the immune system?

Answer 10

Infectious diseases prevented by vaccination, protection gained by vaccination vary widely depending on pathogen
Different individuals produce different immune responses upon infection by some pathogens that can cause chronic disease

Question 11

What is transplantation in the immune system?

Answer 11

Treat patients by removal of a non functioning organ and replacing it with another one more functional (from human or animal)
inevitably leads to rejection of foreign organ unless steps are taken to prevent immune system from recognizing the transplanted organ as foreign

Question 12

What is cancer in the immune system?

Answer 12

The hope that cancer cells are different from non-malignant self cells, and cancer cells can be recognized and attacked by immune system has been expressed by researchers for years

Question 13

What are antibodies in the immune system?

It’s types and their structure?

Answer 13

Study basic unit of antibody on page 23
2 light chains and 2 heavy chains
First half of light chain is variable region or domain and second half is constant region or domain
7 different classes of constant heavy chain regions (IgM, IgA, IgE, IgG1-IgG4)
IgG and IgE made from one basic unit
IgA can be made up of one or more units
IgM contains 5 units

Question 14

What is binding site of antigen on an antibody?

Answer 14

Variable region of one heavy and one light chain constitute one antigen binding site
Page 23

Question 15

What is lattice formation?

Answer 15

All antibody molecules can bind to more than one antigen molecule, and all antigen molecules can bind more than one antibody molecule which makes lattice formation

Precipitin reaction is due to lattice formation

Page 24

Question 16

What is the clonal selection theory?

Answer 16

Provides basic conceptual framework within which all discussions about immune responses now take place

Question 17

What are the 3 basic elements of the clonal selection theory?

Answer 17

1. Selection
2. Cells able to respond to antigens are clonal
3. Self-nonself discrimination

Question 18

What is selection in clonal selection theory?

Answer 18

Cells of immune system have array of different genes encoding for antibody molecules
Antigen selects good fitting antibodies from the vast array that are premade and waiting to be selected
Page 26 picture

Question 19

What is the cells able to respond to antigen are clonal in the clonal selection theory?

Answer 19

Cells express genes coding for one antibody molecules with unique specificity and bear the corresponding antibody as a receptor on their surface
When antigen links with that antibody the precursor cell makes clone
States that antigens can select precursor cells beating appropriate antibody receptors

Question 20

What is self-nonself discrimination in clonal selection theory?

Answer 20

Generation of precursor cells with different antibody receptors would inevitably result in some being generated that could bind self antigens
Must be a mechanism that allows responses to take place against foreign antigens but prevents those against self antigen

Question 21

What are the 2 pieces of evidence for the clonal selection theory?

Answer 21

1. Cells from spleen can be induced by antigen to produce antibody, cells binding to particular antigen are required to make antibody to this antigen but are not required for an antibody response to other antigens
2. Must be self antigens that distinguish them from foreign antigens, experiments prove this

Question 22

What are major histocompatibility complex molecules? (MHC)

Answer 22

Preforms role in recognition of antigens
Two kinds: Class I (surface of cells) and class II (phagocytic cells)
Class I represents intracellular proteins, spy on whether any new non self proteins are produced in a cell and form immune system to launch attack
Class II is same on phagocytic cells
The grooves in MHC molecules are different throughout people which make viral proteins hard to bind on
Page 29 figure

Question 23

What are antigen specific B cells?

Answer 23

Antibody raised against tetanus toxin binds to this molecule and anti-tetanus toxin will precipitate with the antigen
Generated in bone marrow and once mature they emigrate to lymphoid organs (spleen and lymph nodes)

Question 24

What are antigen specific T cells?

Which T cells bind what?

Answer 24

Generated in thymus
Carried out and regulates immune responses
They differ from B cells in they do not bind antigen itself, but to peptides derived from antigen that are bound to MHC molecules
T cells bearing CD4 antigen or CD4+ T cells bind peptides bound to class II MHC
CD8+ T cells bind to peptides bound to MHC class I