Adaptive,Specific Immunity and Immunization




Production of specific antibodies by dual system of B and T lymphocytes in response to an encounter with a foreign molecule, called an antigen.
Antigen- any foreign molecule, they tend to be big and complex. The are molecules on the surface of a bacteria or a virus.

Primary and Secondary Response to Antigens
Primary Response- after first exposure to an Ag immune system produces IgM and a gradual increase in Ab titer(concentration of antibodies) with the production of IgG.
Secondary Response- after a second contact with the same Ag, immune system produces a more rapid, stronger response due to memory cells- anamnestic response.

Monoclonal Antibodies
-Pure preparation of antibody
-Single specificity antibodies formed by fusing a mouse B cell with a cancer cell.
-Used in diagnosis of disease, identification of microbes and therapy.

Two features that characterize specific immunity:
Specificity- antibodies produced, function only against the antigen that they were produced in response to
Memory- Lymphocytes are programmed to "recall" their first encounter with an antigen and respond rapidly to subsequent encounters

Classifying Acquired Immunities:

1. Blood with antibodies is taken from humans or animals who have had the infection recently.

2. Blood serum containing antibodies is separated from the blood, processed, and injected.

3. Antibodies either attack a current infection or provide short-term protection.

Q: Which of the following is an example of artificial passive immunity?
a. A person who recovers from an infectious disease
b. A person who receives immune serum during treatment for hepatitis
c. A newborn receiving antibodies in breast milk while breast feeding
A: A person who receives immune serum during treatment for hepatitis

Here are a couple videos that may help explain the connections between macrophages, helper T-cells, and B-cells.
Hope they help!




B AND T CELLS- both originate in the bone marrow. B cells stay in the bone marrow while T cells migrate to the Thymus to mature. Both B and T cells migrate to secondary lymphoid tissue.
B cell maturation
Directed by bone marrow sites that harbor stromal cells, which nurture the lymphocyte stem cells and provide hormonal signals. Millions of distinct B cells develop and "home" to specific sites in lymph nodes, spleen, and GALT. Come in contact with antigens throughout life.
T cell maturation
Maturation is directed by the thymus gland and its hormones. 7 classes of T cell receptors termed CD (cluster of differentiation). Mature T cells migrate to lymphoid organs and occupy specific sites.


MHC- Major histocompatibility complex; receptors found on all cells except RBC's. also known as human leukocyte antigen (HLA). Plays a major role in recognition of self by the immune system and in rejection of foreign tissue.
Functions of the MHC
Genes for MHC are clustered in a multigene complex:
-Class 1- markers that display unique characteristics of self molecules and regulation of immune reactions. This is required for T lymphocytes.
-Class 2- receptors that recognize and react with foreign antigens. Located primarily on macrophages and B cells. These are involved in presenting antigen to T- cells
phagolysosome formation and killing- lysosomes migrate to the scene of the phagosome and fuse with it to for m a phagolysosome. other granules containing antimicrobial chemicals are released into the phagolysosome, forming a potent brew designed to poisone and then dismantle the ingested material. the destructiveness of the phagocytosis is evident by the death of bacteria within 30 min after contacting this batter of antimicrobial substances.

Test yourself: What are some functions of the MHC, where are they found and where are they not found, what is a B cell and what is a T cell, where do they originate and what are some functions.

	B cells	T cells
Site of maturation	Bone Marrow	Thymus
Surface markers	Immunoglobulin	CD & T-cell receptors
Receptors for Anitgen	Immunoglobulin	T-cell receptors
Product of Anitgenic stimulation	Plasma cells and memory cells	sensitized T cells and memory cells
Function	Production of antibodies to inactivate, neutralize and target antigens	Helping other immune cells, suppressing, killing abnormal cells, synthesize cytokines

DEVELOPMENT OF THE IMMUNE RESPONSE SYSTEM
Call receptors or markers confer specificity and identity of a cell.
Major functions of receptors are:
1. To perceive and attach to non-self or foreign molecules
2. To promote the recognition of self molecules
3. To receive and transmit chemical messages among other cells of the system
4. To aid in cellular development


B-cells produce 5 classes of antibodies:
IgG- The most common serum antibody. It is predomonate in the plasma. It is the only antibody that can pass from mother to fetus by crossing the placenta during pregnancy, and diffuse across mucosal surfaces. IgG is also present in vaginal secretions. There are four different subcategories of IgG, the major form of immunoglobulin. It coats germs (opsonizes) and makes them easier for germ-eating cells to find.
IgA- A type of immunoglobulin present in small amounts in the blood and body secretions which may aid in fighting infections. An immunoglobulin found in body fluids such as tears and saliva and in the respiratory, reproductive, urinary, and gastrointestinal tracts. IgA protects the body's mucosal surfaces from infection. Colostrum (the first breast milk) is very high in IgA.
IgM-An antibody made locally in mucosal-associated lymphatic tissue. IPredomonate in plasma. It is produced early in the immune response to a pathogen, before IgG. One of many antibodies present in blood serum which is usually indicative of an acute infection.
IgE- Immunoglobulin E (IgE) is an uncommon component unless on is allergic or persons infected with a parasitic worm. IgE can be measured in a blood sample to determine if a person is allergic to a specific allergen. The significance of IgE is to stimulate the inflammation response through the release of basophils and mast cells. A more dangerous role of IgE is to stimulate anaphylaxis, asthma and other serious allergies.
IgD- It binds to B cells as an antigen receptor.

Q: What antibody is a significant component of the mucous and serous secretions of the salivary glands, intestine, nasal membrane, breast, lung, and genitourinary tract?

a. Monomeric IgA
b. Dimeric IgA
c. IgE
A: Dimeric IgA

SCID: In 1984, at the age of 12, David opted for a bone marrow transplant from his sister, in hopes of stimulating development of a functional immune system. Sadly, the bone marrow contained the Epstein Barr virus. David died from Burkitt's lymphoma at age 12.

1976 was marked the birth of immunology. Edward Jenner observed that milkmaids who got cowpox rarely got smallpox. He inoculated patients with cowpox and thus protected them from smallpox.
Clonal Selection Theory • Lymphocytes use 500 genes to produce a tremendous variety of specific receptors. • Undifferentiated lymphocytes undergo genetic mutations and recombination while they proliferate in the embryo. • Form a billion different clones with the ability to react with a tremendous variety ofantigens • In the bone marrow, lymphocytic stem cells differentiate into either T or B cells. • B cells stay in the bone marrow. • T cells migrate to the thymus. • Both T and B cells migrate to secondary lymphoid tissue. Lymphocyte specificity is pre-programmed, existing in the genetic makeup before an antigen has ever entered the system. • Each genetically different type of lymphocyte expresses a single specificity. • First introduction of each type of antigen into the immune system selects a genetically distinct lymphocyte. •
Causes it to expand into a clone of cells that can react to that antigen

1976 Sarah Nelmes had a rash on her hand that she consulted Edward Jenner about . He diagnosed her with cowpox instead of smallpox. One of her cows had recently had cowpox so Edward Jenner decided to test out properties of cowpox by giving it to someone who had not yet had smallpox.
He decided to use the son of his gardener. He scratched a few spots of the boy's arm and rubbed a sample on the scratches from the pox on Sarah Nelmes' hand. A few days later the boy was mildly sick but was fine after a week. This proved that cowpox were able to pass from person to person as well as from cow to person.
Now was the time to test if cowpox could protect a person from getting smallpox. Edward Jenner variolated the gardener's son with smallpox. The boy did not get smallpox and was later tested again multiple times. All came out negative.

Q&A~~Home Page~~Top of Page

Immunity in the News:

Immunization laws and attitudes vary: http://www.latimes.com/news/local/la-me-immunizationlaw29-2009mar29-2009mar29,0,4722042.story
To Immunize or not: http://www.pressdemocrat.com/article/20090402/ARTICLES/904029866/0/NEWS

Vaccination is the introduction into the body of a:
-dead or disabled pathogen
-harmless microbe with pathogen proteins displayed on its surface

Vaccination triggers and immune response without causing an infection:
-circulating memory B cells are produced
--Elicit a quicker and larger immune response in an actual infection

Vaccination may not provide effective defense in the future, if pathogen's surface proteins are altered.

Characteristics	of Subsets of T	Cells
Types	Primary Receptors on T Cells	Functions/Important Features
T helper cell 1 (TH1)	CD4	Activates other CD4 and CD8 cells; secretes IL-2, tumor necrosis factor, and interferon gamma; responsible for delayed hypersensitivity; interacts with MHC II receptors
T helper cell 2 (TH2)	CD4	Drives B-cell proliferation, secretes IL-4, IL-5, IL-6, IL-10; can dampen TH1 activity
T cytotoxic cell (Tc)	CD8	Destroys a target foreign cell by lysis; important in destruction of complex microbes, cancer cells, virus infected cells; graft rejection; requires MHC I for function

flashcards for this chapter are available on www.flashcardexchange.com under Kevin Young's flashcards chapter 15

Questions:

Q&A~~Home Page~~Top of Page

1. B cells are located in the:
a. RBC
b. Bone Marrow
c. Muscle Fibers
d. Thymus

2. ___________ is a substance that provokes an immune response in specific lymphocytes.
a. antigenicity
b. epitope
c. antigen
d. haptens

3. Markers that display unique characteristics of self molecules and regulation of immune reactions, required for T lymphocytes is known as?
a. Class I
b. Class II
c. B-cell receptors
d. T-cell receptors

4. In the bone marrow, lymphocytic stem cells differentiate into either T or B cells. Where do the B and T cells migrate?
a. B cells stay in the bone marrow while T cells migrate to the Thymus
b. B cells mutate into memory cells and lay dormant in the frontal lobe while the T cells stay in the bone marrow
c. B and T cells both go to the Thymus where they operate their specific functions
d. B cells Migrate to the Thymus and T cells stay in the bone marrow

5. Cell surface markers of one individual that are antigens to another of that same species is called:
a. Alloantigens
b. Superantigens
c. Allergen
d. Autoantigens

6. Superantigens are:
a. cell surface markers of one individual that are antigens to another of that same species
b. antigens that provokes allergy
c. molecules on self tissues for which tolerance is inadequate
d. potent T cell stimulator's; provoke an overwhelming response

7. An antigen that provokes allergy is called a:
a. Alloantigens
b. Superantigens
c. allergen
d. Autoantigens

8. An autoantigen is:
a. molecules on self tissues for which tolerance is inadequate
b. antigen that provokes allergy
c. Not antigenic unless attached to a larger carrier
d. provoke and overwhelming response

9. Which of these factors is NOT a major factor in adaptive or acquired immunity?
a. specificity
b. chemotaxis
c. recognition
d. memory

10. The primary b-cell receptor is ?
a. IgD
b. IgA
c. IgE
d. IgG

11. In humans, B cells mature in the -------------, and T-cells mature in the ----------------- ?
a. GALT, Liver
b. bursa, thymus
c, bone marrow, thymus
d. lymph nodes, spleen

12.Which type of cell actually secretes antibodies?
a. T cell
b. macrophage
c. plasma cell
d. monocyte

Definitions

Alloantigens- cell surface markers of one individual that are antigens to another of that same species.
Superantigens- potent T cell stimulator's; provoke an overwhelming response.
Allergen- antigen that provokes allergy.
Autoantigens- molecules on self tissues for which tolerance is inadequate.
Natural immunity- acquired as part of normal life biological experiences
Artificial immunity-acquired through a medical procedure such as a vaccine
Natural active immunity- acquired upon infection and recovery
Natural passive immunity- acquired by a child through placenta and breast milk
Artificial active immunity-acquired through inoculation with a selected Ag
Artificial passive immunity-administration of immune serum or vaccine (antibodies) from human or animal donor
Active immunity- results when a person is challenged with antigen that stimulates production of antibodies; Creates memory, takes time and is lasting
Passive immunity- preformed antibodies are donated to an individual; does not create memory, acts immediately, and is short term.