Chapter 17

Which kind of immunity provides protection against bacterial toxins?

humoral

Match the choices below with the following statements. a. IgA, b. IgM, c. IgG, e. IgE 1. Ab that protect the fetus & newborn. 2. First Ab produced after an initial exposure to Ag. 3. Ab bound to mast cells & involved in allergic reactions. 4. Ab found in tears, mucus, saliva.

1. IgG 2. IgM 3. IgE 4. IgA

Describe the steps of how a virus-infected cell or cancer cells is killed by a cytotoxic T lymphocyte.

1. Infected or cancerous cell produces abnormal endogenous antigens. 2. Abnormal antigen is presented with MHC I. 3. T helper cell binds and promotes secretion of cytokines 4. Cytokines activate a precursor CTL which produces clones of CTLs 5. CTL induces destruction of infected cell by apoptosis.

Briefly describe activation of T helper cells

1. Ingestion and digestion of bacteria. 2. MHC bind with antigen and present to outside of cell. 3. T helper cell binds and promotes secretion of cytokines.

Describe activation of T helper cells.

1. Ingestion of microorganism. 2. Antigen processed and combines with MHC II displayed on surface of APC. 3. Receptor on surface of CD4+ T helper cell binds to MHC-antigen complex. Costimulatory molecule secreted by APC causes production of cytokines. 4. Cytokines cause T helper cell to become activated and then proliferates.

Name each of the following examples and explain why: 1. Immunity resulting from infection. 2. Transplacental or via colostrum (milk). 3. Injection of Ag (vaccination). 4. Injection of Ab.

1. Naturally acquired active immunity. 2. Naturally acquired passive immunity. 3. Artificially acquired active immunity. 4. Artificially acquired passive immunity.

There are approximately _____________ different B cells with different specificities.

10 trillion

What is a hapten?

A low-molecular-weight compound which is not antigenic on its own. However, when attached to a carrier molecule (often plasma protein) it becomes antigenic. Antibodies will then be produced. Penicillin can sometimes become inactivated as they are a hapten, responsible for penicillin allergy.

Is immunological memory associated with active or passive immunity?

Active immunity has immunological memory.

Is active or passive immunity long-lived?

Active immunity is long-lived. Passive immunity is temporary.

Name four consequences of antigen-antibody binding (there are technically five, but only know these four)

Agglutination (reduces number of infectious units to be dealt with; helps remove bacteria more efficiently) Opsonization enhances phagocytosis. Neutralization (Blocks adhesion of bacteria and viruses to mucosa; blocks attachment of toxin) Complement activation (causes inflammation and cell lysis)

Compare and contrast Antibody-mediated and Cell-mediated immunity.

Antibody-immunity involve B lymphocytes and anti-bodies made by plasma cells. (Plasma cells are descendants of B cells). Defend against extracellular bacteria, bacterial exotoxins, extracellular viruses. Cell-mediated immunity involve T lymphocytes, and other cells recruited by cytokines (macrophages and NK cells). Defend against intracellular bacteria, viruses within cells, cancer cells, transplanted tissue.

Define antigen.

Antigens are large proteins or polysaccharides which cause the body to produce specific antibodies or sensitized T cells. Usually they were non-self, or foreign, to the body. Components of microbes that are antigens are capsules, cell walls, flagella, fimbriae, exotoxins, viral capsids.

Name three APCs

B cells (in humoral immunity) Dendritic cells Activated macrophages

When T cytotoxic cells (CD8+ cells) are activated they divide and differentiate into....

Cytotoxic T lypmhocytes (CTLs) and Memory T cells. CTLs release perforin (pokes holes in cell) and granzymes (digestive enzyme) which lead to apoptosis of infected target cells or tumor cells.

What is the target cell for HIV?

Helper T cells (include TH1, TH2, TH17)

What is the most prevalent immunoglobulin in the blood? List the immunoglobulins in order of decreasing prevalence in the blood.

IgG G 80% A 10-15% M 5-10% D 0.2% E 0.002%

Describe three ways secondary response is different from primary response.

IgG predominates. FASTER Second exposure occurs much faster; no lag time. STRONGER More antibody produced in secondary response.

What is the "early antibody" and what is the "late antibody?"

IgM - EARLY IgG - LATE

Compare and contrast natural versus artificial immunity.

Medical intervention involvement.

Compare and contrast active versus passive immunity.

Memory cell involvement Active: the individual develops their own antibodies or activated T cells Passive: the individual receives antibodies from another individual or source.

When a B cell is activated, it divides and differentiates into ___________ and _____________. Describe nature of each of these.

Memory cells respond more rapidly and aggresively upon future exposure to antigen. Plasma cells make immunoglobulins.

NK versus CTL

NK do not recognize antigen like CTL (not immunologically specific). They recognize that something is "weird" about the cell.

Is active or passive immunity immediately effective?

Passive immunity is immediately effective. Active immunity has a delay.

What is gamma globulin

Portion of serum which contains antibodies.

Which immunoglobulin is more prevalent in primary response? Which immunoglobulin is more prevalent in secondary response?

Primary - IgM Secondary - IgG

Compare primary and secondary response.

Primary occurs after initial contact with antigen. Secondary occurs after second exposure.

Define opsonization and state two substances that perform this activity.

Promotes attachment of phagocyte to microbe. C3b binds to microbe surface. What is second substance

Describe IgA. Shape: Percentage of serum Abs: Location: Functions:

Shape: Dimer Percentage of serum Abs: 10-15% Location: Secretions; rich supply in colostrum (baby animals) Functions: mucosal protection

Describe IgE. Shape: Percentage of serum Abs: Location: Functions:

Shape: Monomer Percentage of serum Abs: 0.002% Location: On mast cells, on basophils, and in blood. Functions: Allergic reactions; lysis of parasitic worms.

Describe IgD. Shape: Percentage of serum Abs: Location: Functions: Technically, don't need to know

Shape: Monomer Percentage of serum Abs: 0.2% Location: Blood, lymph, and on B cells. Functions: Initiate immune response.

Describe IgG. Shape: Percentage of serum Abs: Location: Functions: Unique characteristics:

Shape: Monomer Percentage of serum Abs: 80% Location: Blood, lymph, intestine. Function: Enhances phagocytosis, neutralizes toxins and viruses, protects fetus and newborn. Complement Fixation Unique characteristics: Crosses placenta, lasts for 4-6 weeks (initially temporary), "LATE" antibody

Describe IgM. Shape: Percentage of serum Abs: Location: Functions: Unique characteristics:

Shape: Pentamer Percentage of serum Abs: 5-10% Location: Blood, lymph, on B cells Functions: Agglutinates microbes Complement Fixation Unique characteristics: First Ab produced in response to infection, "EARLY" antibody, made by baby.

What are the general functions of T helper cells?

Stimulate macrophages, B cells to make Ig, increase activity of complement, activate Tc cells and NK cell Stimulates eosinophils, mast cells, basophils. Stimulate inflammation and recruit neutrophils. In general, they have MANY functions, they are like a general. They give orders but don't actually kill anything.

Define serology.

Study of reactions between antibodies and antigens. Some diseases are diagnosed, not by identifying pathogen, but instead by detecting antibodies to it (ELISA)

Describe job of T regulatory cells.

Suppress T cells that might be reactive against self. Also protect, from the immune system, intestinal bacteria required for digestion and other useful functions. They may also play a role in protecting the fetus from rejection of nonself.

____ cells require APCs

T cells B cells do not.

_________ cells deal directly with viral-infected and tumor cells by presenting ________ on surface of infected cell.

T cytotoxic cells MHC

Name the marker on surfaces of the following T cells: T helper cells T cytotoxic cells T regulatory cells.

T helper cells - CD4+ T cytotoxic cells - CD8+ T regulatory cells - CD4 CD25

Compare and contrast T-dependent antigens and T-independent antigens.

T-dependent antigens. They need help of cytokines secreted by T helper cells (double stimulation process). They are usually proteins T-independent antigens don't require T helper cell help. They are usually polysaccharides.

T cells attach to antigen by ___________

TCR (T cell receptor)

Match cell with function. 1. T Helper (TH1) Cell 2. T Helper (TH2) Cell 3. T Helper TH17 Cell 4. Cytotoxic T Lymphocyte 5. T Regulatory Cell 6. Activated Macrophage 7. NK Cell A. Stimulates production of eosinophils, IgM, IgE. B. Regulate immune response and helps maintain self-tolerance. C. Enhanced phagocytic activity; attacks cancer cells. D. Attacks and destroys target cells; participates in antibody-dependent cell-mediated cytotoxicity. (similar to CTL but not as specific) E. Recruit neutrophils; stimulate production of antimicrobial proteins. F. Activate (macrophages, T cytotoxic cells, NK cells) G. Destroy target cells on contact; generated from T cytotoxic cell.

TH1 Activate (macrophages, T cytotoxic cells, NK cells) TH2 Stimulates production of eosinophils, IgM, IgE. TH17 Recruit neutrophils; stimulate production of antimicrobial proteins CTL Destroy target cells on contact; generated from T cytotoxic cell. T regulatory cell regulate immune response and helps maintain self-tolerance. Activated macrophage have enhanced phagocytic activity; attack cancer cells. NK cells attack and destroy target cells; participate in antibody-dependent cell-mediated cytotoxicity (similar to CTL but not as specific)

NK cells are not B cells or T cells. They are lymphocytes. True or False

TRUE

Antigens do NOT need to be presented to B cells. True or False

True

Describe general structure of immunoglobulins (antibodies).

Two heavy chains, two light chains. Two Fab binding sites which bind to epitopes One Fc (stem) region. Chains are attached by disulfide bonds.

Define antibody titer

amount of Ab in serum

Define immunoglobulins

antibodies

How do cells in the immune system communicate with each other?

cell-mediated

Which kind of immunity is responsible for rejection of transplanted tissue?

cell-mediated

Which kind of immunity provides protection against intracellular pathogens like TB or like many viruses?

cell-mediated

Which kind of immunity provides protection against some cancers?

cell-mediated

T cells (T subunit c) can differentiate into _____________.

cytotoxic T lymphocytes (CTLs)

Define seroconvert

from not making antibodies to making antibodies

IgG, IgD, IgE are __________. IgM is ______ and IgA is ________.

monomers; a pentamer; a dimer

Define globulins

serum proteins

B cells and T cells originate from ______________. They then diverge and develop in the __________ and __________. B cells develop in the __________ and T cells develop in the ___________. The two types of cells then migrate to lymphoid tissues such as spleen, but especially lymph nodes.

stem cells in bone marrow (or fetal liver) red bone marrow of adults; thymus red bone marrow in adults; thymus