Micro Chapter 15 (Mult Choice + T/F), Micro Chapter 15 (SA)

What are the five principal stages of an immune reaction?

1. Lymphocyte development and differentiation 2. The presentation of antigens 3. The challenge of B and T lymphocytes by antigens 4. B lymphocytes and the production and activities of antibodies 5. T lymphocyte responses

The major histocompatability complex is:

A. glycoproteins, called MHC antigens, found on all body cells except red blood cells

Plasma cells:

A. secrete antibodies

The immunoglobulin class that has a dimer form found in mucus, saliva, colostrum, and other body secretions is:

A.IgA

What are the functions of plasma cells and memory cells?

Activated B lymphocytes become plasma cells that produce and secrete large quantities of antibodies. Some activated B cells become memory cells which are persistent, long term cells that can react with the same antigen on future exposures.

Compare active and passive immunity.

Active immunity: An immune stimulus activates the B and T cells to cause an immune response. It creates a memory that enables a person to react quickly next time. It takes several days to develop and lasts for a long time, sometimes life long. Passive Immunity: An individual receives antibodies that were developed in a human or animal donor. It lacks memory, gives a short term protection, Can be natural or artificial.

Which is incorrect about the Fc region of an immunoglobulin?

B. forms the antigen binding sites

Small foreign molecules that are too small by themselves to elicit an immune response are termed:

B. hapten

Which process involves antibodies coating microorganisms in order to facilitate phagocytosis?

B. opsonization

Class I MHC genes code for:

B. self receptors recognized by T lymphocytes

The embryonic yolk sac, the liver, and the bone marrow are sites where:

B. stem cells give rise to immature lymphocytes

These cells carry CD8 receptors and function to inhibit B cells and other T cells:

B. suppressor T cells

Superantigens are:

C. bacterial toxins that activate T cells at a 100 times greater rate than other antigens

The most significant cells in graft rejection are:

C. cytotoxic T cells

An example of artificial passive immunity would be:

C. giving a person immune serum globulins to chickenpox virus after exposure to the disease

Cytotoxic T cells:

C. secrete lymphotoxins and perforins that damage target cells

The immunoglobulin/s found on the surface of B cells is/are:

D. IgM and IgD

The monomer subunit of immunoglobulin molecules has all the following except:

D. four antigen binding sites

Properties of effective antigens include all the following except:

D. large polymers made up of repeating subunits

The progeny cells of a B-cell clone are called:

D. plasma cells

Class II MHC genes code for:

D. receptors located primarily on macrophages and B cells

The immunoglobulin class that is the only one capable of crossing the placenta is:

D.IgG

Helper T cells:

E. activate B cells and other T cells

These lymphocytes lack specificity for antigen and are cells that attack cancer cells and virus-infected cells:

E. natural killer (NK) cells

After secreting antibodies during an immune response, plasma cells then differentiate into memory cells. T/F

False

Antibodies are secreted by monocytes. T/F

False

Antibodies directed to alloantigen from one organism often cross-react with alloantigens from another organism. T/F

False

Human B lymphocytes mature in an intestinal region called the bursa. T/F

False

IgE antibodies are found in body secretions. T/F

False

The hinge region of an antibody has a hypervariable amino acid region where the antigenic determinant fits. T/F

False

The process of reducing the virulence of microbes so that they can be used in vaccines is called denaturation. T/F

False

Vaccination could be described as artificial passive immunity. T/F

False

What is hapten? Give 3 examples.

Haptens: Are small foreign molecules that can not provoke an immune reaction by themselves. But, a hapten bound to a larger carrier molecule will serve as an immunogen. Ex; drugs, metals and chemicals.

Describe MHC. How it participates in immune reactions?

Major histocompatibility complex (MHC): MHC is a set of genes that code for cell receptors. This gene complex gives rise to a set of glycoproteins called MHC molecules that are present in all nucleated human cells. It is also known as Human leukocyte antigen system (HLA). This system is responsible for the discrimination between self and non-self. MHC I: Responsible for recognition of self molecules. MHC II: Code for immune regulatory receptors.

Describe opsonization and agglutination.

Opsonization by opsonin: Opsonins are antibodies that stimulate opsonization, a process in which microorganisms are coated with specific antibodies so that they'll be more readily recognizable. Agglutination is the clumping of antigens by the antibodies which renders microbes immobile and enhances phagocytosis.

Compare the primary and secondary response to antigen.

Primary response and latent period: Upon the first exposure to an Ag, the system undergoes a primary response. Earliest part of primary response is the latent period when the antigen is being processed, but the antibodies are not produced yet. Secondary and anamnestic responses (basis of boosters): When the immune system is exposed again to the same antigen, secondary response occurs. Secondary response is also called anamnestic response as the memory cells recall the first encounter with antigen and respond in a very quick and potent way.

Compare & Contrast B cells & T cells (at least 3 contrasting features).

T CELLS= ‌•only recognizes antigens attached to presenting cells ‌•mature & proliferate in Thymus ‌•Secretes cytoxic T-cells destroys infected cells ‌•its T-memory cells increase cytotoxic T cells ‌B CELLS= ‌•can recognize free floating antigens ‌•mature & proliferate in spleen & lymph nodes know as Humoral ‌•secretes antibodies against a specific antigen ‌•B memory cells reside in lymph nodes for later use

Activation of B cells occurs when antigen binds to B cell surface immunoglobulin receptors. T/F

True

Antibody molecules circulate in lymph, blood, and tissue fluids. T/F

True

Cell surface markers are also ofter called receptors. T/F

True

Class I, II, and III MHC genes are located on the sixth chromosome of humans. T/F

True

One plasma cell will secrete antibodies of various classes but the antibodies will all have the same specificity. T/F

True

The albumin fraction of serum separated by electrophoresis will contain most of the antibodies. T/F

True

The structural and functional differences that distinguish immunoglobulin isotypes are due to variations associated with their Fc fragments. T/F

True

What functions do receptors play in specific immune response?

a. Attach to non-self molecules b. Promote their self recognition c. Receive and transmit chemical messages among other cells d. Aid in cellular development

The primary B-cell receptor is:

a. IgD

Small, simple molecules are ______ antigens.

a. poor

Tc cells are important in controlling:

a. virus infections

The cross-linkage of antigens by antibodies is known as:

c. agglutination

In humans, B cells mature in the ______ and T cells mature in the _______.

c. bone marrow, thymus

T _____ cells assist in the functions of certain B cells and other T cells.

c. helper

A vaccine that contains parts of viruses is called:

c. subunit

Conjugated vaccines combine combine antigens and _________.

d. foreign proteins

Widespread immunity that protects the population from the spread of disease is called:

d. herd immunity

Which of the following can serve an antigen-presenting cells (APCs)? b. B cells c. macrophages d. dendritic cells e. b, c & d

‌• B cells ‌• macrophages ‌• dendritic cells E.B,C,D

Cell surface markers involved in immune reactions: A. are the result of genetic expression B. function in recognition of self molecules C. receive and transmit chemical messages among other cells of the system D. aid in cellular development E. all of the choices are correct

‌•are the result of genetic expression ‌•function in recognition of self molecules ‌• receive and transmit chemical messages among other cells of the system ‌• aid in cellular development E. all of the choices are correct

Antigen presenting cells: A. include dendritic cells B. include macrophages C. engulf and modify antigen to be more immunogenic D. hold and present processed antigen on their cell membrane surface E. all of the choices are correct

‌•include dendritic cells ‌•include macrophages ‌•engulf and modify antigen to be more immunogenic ‌• hold and present processed antigen on their cell membrane surface E. all of the choices are correct

Monoclonal antibodies: A. originate from a single B cell clone B. have a single specificity for antigen C. are secreted by hybridomas D. are used in immunology lab tests and cancer therapy

‌•originate from a single B cell clone ‌• have a single specificity for antigen ‌• are secreted by hybridomas ‌•are used in immunology lab tests and cancer therapy E.ALL OF THE CHOICES ARE CORRECT

Lymphocytes: A. possess MHC antigens for recognizing self B. have membrane receptors that recognize foreign antigens C. gain tolerance to self by destruction of lymphocytes that could react against self D. develop into clones of B and T cells with extreme variations of specificity E. all of the choices are correct

‌•possess MHC antigens for recognizing self ‌•have membrane receptors that recognize foreign antigens ‌•gain tolerance to self by destruction of lymphocytes that could react against self ‌•develop into clones of B and T cells with extreme variations of specificity E. all of the choices are correct