Patho- Chapter 7 Adaptive Immunity

What molecules directly recognize antigens?

(1) Circulating antibodies (2) Antigen receptors on B cells or B-cell receptors (BCR) (3) Antigen receptors on T lymphocytes or T-cell receptors (TCR)

Which of the following may occur when an antibody attaches to an antigen? (Select all that apply) Causes Mast cells to release histamine resulting in an allergic response Activates the complement system Coats the pathogen which causes macrophages to engulf and destroy it Presents the antigen to T-cells

Causes Mast cells to release histamine resulting in an allergic response Activates the complement system Coats the pathogen which causes macrophages to engulf and destroy it The only incorrect option is antigen presentation to T-cells. This is the role of type 2 major histocompatibility proteins (MHC-2).

CD-8 or __________________ recognize ALL nucleated cells and associate with _____________ whereas CD-4 or __________________________ recognize only "Professional" antigen presenting cells (macrophages and dendritic cells) and associate with ______________________.

Cytotoxic T-Cells MHC I Helper T-Cells MHC II

When and where do T cells develop cell surface markers?

During maturation in the Thymus

CD-8 Cytotoxic T-Cells

recognize ALL nucleated cells and will destroy them if they present something that is non-self CD-8 recognizes MHC-1

What is the antigen's binding site called?

Epitope (antigenic determinant)

(T/F) Active immunity against a new pathogen is achieved much more quickly than passive immunity.

False In active immunity, an individual is exposed to an antigen, the immune response begins, and antibodies are formed in 7 to 10 days. In passive immunity, antibodies are created outside the host and injected, giving the individual immunity immediately.

IgE Shape, general function and most prevalent for what situation?

Fxn: found on mast cells in tissues; starts inflammation; involved in allergy prevalent situation: for type 1 hypersensitivities/ allergies/ mast cells Shape: monomer

What is a locally secreted immunoglobulin? What is their #goal?

IgA Halt viral and bacterial invasion

What are immunoglobulins that mediate allergic responses? What can it bind to? How concentrated is it in circulation?

IgE Binds to allergens and parasites Least concentrated (wouldn't want to be activating allergic responses all over, all the time)

What is the most abundant class of immunoglobulin? What can it cross?

IgG Crosses the placenta

What are the first antibodies produced during a primary response to an antigen? When is it synthesized? What is a special characteristic?

IgM (remember IgMe FIRST!) It is synthesized during fetal life Largest (think IgMassive!)

Specificity of the Immune System (2 types)

Immune cell receptors or antibodies bind to epitopes on antigens 1. Monoclonal antibodies are specific for ONE epitope ● in pharmacology these are called Mabs 2. Polyclonal antibodies bind several different epitopes the use of antibodies in treatment is a growing field

What do both humoral and cell-mediated immunity provide?

Immunity and memory

How is immunity provided for fetal and neonatal

Immunity is provided by maternal antibody (Newborn IgG levels are near adult levels)

What are molecules that can trigger an immune response?

Immunogens (basically an antigen that is antigen-y enough to cause an immune response)

Describe fetal and neonatal immunity

In fetal and neonatal immunity antibody function is deficient ● Capable of primary IgM response; UNABLE TO PRODUCE AN IgG CHALLENGE (good because IgG can cross the placenta) ● Immunity is provided by maternal antibody (Newborn IgG levels are near adult levels)

Which is a quicker response, innate or adaptive immunity?

Innate Adaptive take longer bc more specific

innate vs adaptive immunity UNFINISHED

Innate immunity: An individual's genetically predetermined resistance to certain diseases. Adaptive immunity: Ability of the body to react to specific microbial infection. ANTIGEN SPECIFIC

___________ is a great marker for success in organ donation.

MHC

MHC

Major Histocompatibility Complex means tissue compatibility function: presenting those proteins outside the cell

How many antigens does an individual B or T cell recognize?

Only one!!

What is the antibody or lymphocyte's binding site called?

Paratope (Antigen-binding site)

A mother brought her infant son of less than one year into a clinic for a routine checkup. A child that was near the baby at the clinic was later found to be infected with measles. One treatment option would be to inject antibodies against measles directly to the infant since the infant is too young to be vaccinated. What kind of immunity would this provide the baby? Cellular Memory Active Passive

Passive There are two types of adaptive immunity: passive and active. Passive immunity occurs when preformed antibodies are transferred from donor to recipient. An example is the passage of maternal antibodies across the placenta to the fetus or (in this case) injecting antibodies directly into another person that has been exposed. An individual produces active immunity after natural exposure or immunization. Cellular, or cell-mediated, immunity, occurs when effector T cells are formed in the blood and tissues and defend against intracellular pathogens and cancer cells. Memory cells are formed through both cellular and humoral immunity, and they remember the antigen. They respond more efficiently and effectively.

What is short-lived immunity transferred from a donor to a recipient? What are some example of this?

Passive Immunity Breast fed infants

Immature lymphocytes mature by migrating through what kind of lymphoid tissue? What is taking place?

Primary (thymus & fetal liver) Clonal diversity

antigen

something that is recognized by the immune system, usually a protein

What kind of protection is provided by the adaptive immune system?

Provides long-term protection (memory)

What does the adaptive immune system protect against? Give examples.

Recognizes foreign or "nonself" substances Antigens: - Pathogens - Noninfectious environmental agents (pollen, bee venom) - Drugs - Vaccines - Transfusions - Transplants

Innate immunity is a nonspecific response, but adaptive immunity is a _____ response?

specific

Immunocompetent lymphocytes reside in what kind of lymphatic tissue? What can occur there if they bind with a foreign antigen?

Secondary (spleen, lymph nodes, tonsils, adenoids) Clonal Selection

What makes up cell-mediated immunity?

T-Cells T-Cell production of antibodies (cytotoxic t cells) can kill pathogens hiding inside cells (CD-8) phagocytic cells that attack the specific antigen

Antigen presenting cells present parts of a potential pathogen to which of the following cells? T-cells Eosinophils Macrophages Neutrophils

T-cells When pathogens enter the body they are detected and engulfed by cells such as macrophages and dendritic cells (and B-cells in some instances). They then break down those antigens and present them to T-cells. This presentation is what launches a systemic response against the pathogen.

Why would secondary lymphoid tissue swell when an antigen is present?

The B/T cells that reside there are differentiating at a high rate since they have been activated (clonal selection)

What portion of the immunoglobulin binds to an antigen?

The antigen-binding fragment

All but which of the following is true about CD4 receptors? They differentiate in the thymus. They can be found on T helper cells. They attach to MHC II proteins. They destroy infected cells.

They destroy infected cells CD4 receptors do all of those things, but they do not destroy infected cells (the CD-8 cytotoxic T cell does that). CD4 receptors are found on helper T cells which mature in the thymus, where cells carrying receptors that react to self antigens are eliminated.

Why do some infants need booster vaccinations under 1 year of age? They primarily produce IgM which is less effective at long term immunity than IgG They do not have an immune system until 12 months It's just a way for big vaccine to make money They have more adipose tissue

They primarily produce IgM which is less effective at long term immunity than IgG A fetus cannot make IgG, but rather they can only make IgM. After the infant is born it begins to develop the ability to make IgG, but this process takes up to a year. IgM can fight off diseases to some extent, but it is not as effective for long term immunity as IgG. Infants have an immune system, but it is largely dependent on IgM antibodies. It's true that infants have a higher proportion of adipose tissue, but this would not significantly interfere with their immune function. Big vaccine may make money from vaccines, but that isn't the scientific medical reason. Construction workers make money too, but that isn't why you need a place to live.

What will occur if a T cell is presented with "self-antigen"?

They will be destroyed through peripheral tolerance/clonal deletion (don't want self to be hurt)

epitope

the specific site on an antigen that the immune system recognizes

What does cell-mediated immunity primarily protect against? How does it happen?

Viruses & Cancer (inside a cell) T cells will directly kill the target or will stimulate other things (B cells) to attack it

Humoral and cell mediated are types of

adaptive immunity

The presence of what initiates clonal selection?

antigen

Where do T cells mature?

thymus

Where do B cells mature?

bone marrow

What region of an antigen is recognized by an antibody?

epitope

IgD Shape, general function and most prevalent for what situation?

fxn: acts an an antigen receptor to turn into other antibodies prevalent situation: found on the surface of B cells Shape: monomer

IgG General function and most prevalent for what situation?

fxn: circulates in body fluids, binding antigens prevalent: for most systemic infections ● MOST ABUNDANT ● **CROSSES BLOOD VESSELS AND THE PLACENTA** ● also Rh antigen so Rh- mom producing antibodies can affect the Rh+ fetus SHAPE: monomer

IgM Shape, general function and most prevalent for what situation?

fxn: circulates in body fluids; has five units to pull antigens together into clumps (agglutination) prevalent: agglutination (clumping of blood) ● Also antibody formed against A and B blood types but too large to cross placenta so the baby is safe SHAPE: pentamer

IgA Shape, general function and most prevalent for what situation?

fxn: prevent antigens from entering the body prevalent: secretions, including breast milk ● found in secretion on mucous membranes SHAPE: dimer

CD-4 Helper T-Cell

have a protein called CD-4 and only recognize MHC-2

Even though NK cells are part of the lymphocyte cell line, they are categorized with ________ __________ because they are not specific!!!!

innate immunity

adaptive immunity

(specific immunity) acquired ability to recognize and destroy a pathogen or its products. -a stronger, more prolonged, and more effective response to a specific pathogen -Requires exposure of the immune system to the pathogen -Response is faster and more intense upon repeated exposure to a specific pathogen (memory cells) Mechanisms include: -Humoral immunity- antibodies from B cells -Cell-mediated immunity- T cells

key cells of adaptive immunity include:

lymphocytes (B & T cells) Macrophages and dendritic cells (fxn as antigen presenting cells)

Antigen Presenting Cells

macrophages and dendritic cells function as this to activate T cells-- even though they are not lymphocytes, they work with the lymphocytes for the adaptive response.

When referring to the word "antigen", which of the following best describes what an antigen is? A protein molecule that presents pathogenic molecules to T-helper cells An entire bacteria A protein or other structure found on the bacteria A type of antibody that attacks a pathogen

A protein or other structure found on the bacteria An antigen is something that activates an immune response. These are usually proteins that are contained on or within a protein or virus (or foreign cell). We can't really say that the entire bacteria is an antigen because there are many antigens in every bacteria. Antibodies bind to antigens. They are not antigens A protein molecule that presents pathogenic molecules to T-helper cells more accurately describes MHC-2 molecules. They are not antigens, but rather they present antigens.

Which of the following statements is true? A virus "hiding" inside a cell will be detected by a CD-4 Cytotoxic T-cell A virus "hiding" inside a cell will be detected by a CD-8 Helper T-cell A virus "hiding" inside a cell will be detected by a CD-8 Cytotoxic T-cell A virus "hiding" inside a cell will be detected by a CD-4 Helper T-cell

A virus "hiding" inside a cell will be detected by a CD-8 Cytotoxic T-cell Cell mediated immunity is achieved by CD-8 cytotoxic t-cells continuously "sampling" antigens presented by MHC-1 on every cell in your body. If a virus is inside the cell, its proteins will eventually be presented on MHC-1 and CD-8 cells will destroy that cell. CD-4 Helper T-cells do not destroy infected cells. That is the role of cytotoxic (CD-8) T-cells.

MHC 1

molecules found on every body cell that presents antigen; signals cytotoxic T to destroy

MHC II

molecules found on macrophages, B cells, and activated T cells; signal helper T cells found only on antigen presenting cells which are macrophages and dendritic cells

Basic function of NK cells

natural killer cells destroy malfunctioning cells that stop expressing "self" proteins at all (missing MHC) ● this includes many virus-infected cells thay may go on to become tumors *Do not undergo maturation in the thymus lack antigen-specific receptors

What is long-lived immunity resulting from natural exposure to an antigen? What is an example?

Active Immunity Exposed to flu -> get flu -> immuneFlu shot -> immune

active immunity

occurs when the lymphocytes are exposed to foreign antigens in the body

passive immunity

occurs when we receive antibodies made elsewhere (placenta or mother's milk) IgG

What are antibodies produced by?

plasma cells B- cells

What is deficient in fetal and neonatal immunity?

Antibody function

What do antibodies recognize? What are they also called?

Antigens Immunoglobulin (Ig)

What molecules can react with antibodies and receptors on B and T cells? What are they usually composed of?

Antigens Proteins (but can be other things)

What are the primary components of humoral immunity? What do they do?

B cells & Circulating antibodies Cause direct inactivation of a microorganism or the activation of inflammatory mediators (complement system).

lymphocytes

B cells and T cells

Which immune cell creates antibodies in response to antigens? B lymphocytes Cytokines Helper T lymphocytes Cytotoxic T lymphocytes

B lymphocytes Remember that antibodies are created in response to antigens. B lymphocytes have antigen receptors and are activated to produce antibodies against that antigen if a T helper cell directs them to do so.

What makes up humoral immunity?

B-Cell production of antibodies (Helper T Cells) free floating fluid antibody proteins in the blood that attack the specific antigen

What does humoral immunity primarily protect against?

Bacteria & Viruses (from outside a cell)