Chapter 18

B-cells present antigens to helper T-cells (CD4)for _______?

- Antibody formation

What does CD stand for? How are CDs important to T-cell function?

- Clusters of differentiation (CD) • Important for adhesion to receptors

What is meant by the "dual nature of adaptive immunity"? Discuss the two basic divisions of adaptive immunity and describe their primary targets?

- Humoral immunity: Due to antibodies B-cells mature in the bone marrow(progenitor cells of B cells produced in Bone marrow) - Cellular immunity: Due to T-cells, T-cells mature in the thymus(progenitor cells of B cells produced in bone marrow) •target lysed cell

Cytotoxic T-Lymphocytes (CTLs) destroy ______ via apoptosis. What is apoptosis?

- Viral infected cells - programmed cell death

Briefly discuss HIV infections with respect to the effects on helper T-cells(CD4).

-(HIV) human immunodeficiency virus: HIV enters Helper T-cells (CD4). Causes replication of the virus, and death of lymphocytes.

How many different classes of antibodies does the human body produce?

-5 classes

Describe the structure of an antibody, including the control and variable, as well as heavy chains and light chains.

-Antibodies: globular proteins called immunoglobulins (Ig). -Structural: 2 binding sites 2 small =Light chains 2 big = Heavy chains = control region Variable region is the receptor site

Discuss the primary and secondary(or amnestic) response of the human immune system, given the phenomenon of immunological memory.

-Antibody titer is the amount of Ab in serum. •Primary response: occurs after initial contact with AG. •Secondary response: response occurs after second exposure.

Define antigen. How was an antigen related to an antibody and epitope? Name some structures or substances that are common antigens. What is meant by the term "affinity" when discussing an antigen and antibody.

-Antigen(Ag): A substance that causes the body to produce specific antibodies or sensitized T-cells. •Antibodies; interact with epitopes or, antigenic determinants. - Composed of mostly proteins or large polysaccharides. • capsules, cell walls, flagella, Fimbrae, bacterial toxins, pollen, egg white, peanut. - The strength of the antigen and antibody is called "affinity". In general the closer the physical fit between antigen and antibody, the higher the affinity.

Which type of lymphocyte is responsible for killing virus-infected cells?

-Cytotoxic T-cells

What is the difference between processing of endogenous antigens and that of exogenous antigens?

-Endogenous antigen are presented by MHC Class 1 , -Exogenous by MHC class 11

The major histocompatibility complex MHC is a collection of _______ that encodes molecules of genetically diverse______ That are found on the plasma membrane's of mammalian Nucleated cells. The human immune system is capable of recognizing a mind-boggling number of different antigens; estimates are of a minimum of ______ antigens!

-Genes -Glycoproteins -10 to the 15 antigens

Discuss what is meant by the four major types of adaptive immunity, which are as follows: naturally acquired active immunity, naturally acquired passive immunity, artificially acquired active immunity, and artificially acquired passive immunity.

-Naturally acquired active immunity: • resulting from infection -Naturally acquired passive immunity: • transplacental or via colostrum -Artificially acquired active immunity: • injections of antigen,Ag (Vaccination) -Artificially acquired passive immunity: • injection of antibody,Ab

What are the two primary types of lymphocytes?______ are cells that give rise to lymphocytes.

-T-lymphocytes -B-lymphocytes

What is the main function of B lymphocytes?

-To secrete soluble antibodies

Discuss the five results of antigen-antibody binding.

1. Agglutination 2. Opsonization 3. Activation of complement 4. Antibody-dependent cell mediated immunity 5. Neutralization

What is the normal abundance of lymphocytes among white blood cells in human blood.

50-70%

IgA

Dimer 10-15% 6 days No Found in milk

IgE

Monomer 0.002% 2 days No Allergic reaction Parasitic worms

IgD

Monomer 0.2% 3 days No

IgG

Monomer 80% 23 days Yes Protects fetus & newborn

Describe the formation and functions of plasma cells and memory B-cells.

Most members of a clone become plasma cells. The initial plasma cell descendants of any single activated B cell secrete antibodies with binding sites identical to one another and complementary to the specific antigen recognized by their parent cell. Active B cells with BCRs that bind the epitope more closely survive at a higher rate. Thus, as the humoral immune response progresses, there are more and more plasma cells, secreting antibodies whose fitness gets progressively better.

IgM

Pentamer 5-10% 5 days No First antibody produced

________ Is the most common and longest lasting class of antibody in the blood.

• IgG

What is one reason why active immunity is more advantageous than passive immunity?

•Active immunity leads to the development of immunological memory.

Distinguish between the basic functions of B cells and T cells. What is an APC? Which kind of lymphocyte recognizes APCs?

•B-cells: Produce antibodies. •T-cells: recognize antigens only when they are displayed on the surface of a cell. •APC: antigen presenting cells are cells that present antigens to T-cells.

List the sites in the body for early development and later maturation of T cells and B cells.

•Both develop from stem cells early on in red bone marrow -later B-cells mature in bone marrow(B for Bone marrow) -T-cells mature in the thymus(T for Thymus)

Review the major classes/types of antibodies

•IgG, IgM, IgA, IgD, IgE

Discuss the relationship between B-cells, T-cells, virus-infected cells, MHC-1, MHC-11, and APCs.

•T-cells: recognize antigens only where they are displayed on the surface of a cell. •B-cells: And macrophages present an antigen MHC 11 complex to helper T-cells (CD4). • Virus infected cells: present antigens -MHC complex to cytotoxic T-cells (CD8) • APCs: antigen presenting cells are cells that present antigens to T cells.

Contrast T-dependent and T-independent antigens in terms of size and repetition of subunits. Why are those different antigen types called T-dependent and T-independent?

•T-dependent antigens: antigen,Ag, presented with(self) MHC to T h cell (T helper cell) T helper cell produces cytokines that activate the B cell •T-independent antigens: stimulate the B-cell directly to make antibodies,Abs

What is adaptive immunity? List and describe the two basic types of white blood cells involved in adaptive immunity. Define antibody.

•Third line of defense/adaptive immunity -Specialize left the site: T cells and B cells - antibodies •Antibody: Y-shaped Glycoprotein molecule produced by the immune system to stop intruders from harming the body. (Abs) Interact with epitopes, or antigenic determinates.