Exam 2 Study Guide w/ Chapters 15, 16, 17
1) Innate Immunity (p.446): A defenses against pathogens that is present at birth. Two major lines of defense;
1. Physical : Skin (epidermis + dermis) and mucous membranes 2. Internal: Cell and chemicals that inactivate or kill invaders Adaptive immunity (p.446): The body’s ability to recognize and defend itself against distinct invaders and their products. 2) Five attributes of adaptive immunity (p.471)
1. Specificity: When the immune response acts to one specific molecular shape and not against others. 2. Inducibility: When they activate only in response to a specific pathogen. 3. Clonality: Once induced, they clone.
4. Unresponsiveness to self: They do not attack the body “self”. 5. Memory: They recall a particular pathogen, thus responding faster in later encounters.
3) 1st line of defense (p.446): The skin and mucous membranes provide a “barrier” to microorganisms 2nd line of defense (p.450): Composed of cells (phagocytes), antimicrobial chemicals (peptides, complement, interferons), and processes (inflammation, fever). 3rd line of defense (p.471): Adaptive immunity.
4) Mucous membranes (p.447): Mucous membranes line all body cavities open to environment. (i.e. lumens of the respiratory, urinary, digestive, and reproductive tract. nonspecific defenders There are two distinct layers of Mucous membranes:
1. Epithelium: A thin outer covering of the mucous membranes a. Epithelial cells are “living”
b. “Tightly packed” to prevent entry of pathogens
c. Continual shedding of cells carries away microorganisms
2. Deeper connective tissue layer that supports the epithelium Skin composed of two major layers: nonspecific defenders
1. Epidermis: Outer multiple layers of “tightly packed” cells Few pathogens can penetrate these layers. They shed “dead” skin cells which removes
microorganisms. Contain dendritic cells that phagocytize pathogens.
2. Dermis: Deep to the epidermis. Contains hair follicles, glands, and nerve endings. Collagen fibers help skin resist abrasions
Skin has chemicals that defend against pathogens
1. Perspiration secreted by sweat glands
a. Salt inhibits pathogen growth
b. Antimicrobial peptides
c. Lysozyme destroys cell wall of bacteria
2. Sebum secreted by sebaceous (oil) glands
a. Helps keep skin pliable
b. Lowers skin pH to a level inhibitory to many bacteria
5) Lacrimal apparatus (p.449): Produces and drains tears. Blinking spreads tears and washes surface of the eye. Lysozyme (p.447): An enzyme, found in the eye and on skin that destroy cell walls of.
6) The Role of Normal Microbiota in Innate Immunity (p.449): 1. Microbial antagonism: Normal microbiota competes with potential pathogens. 2. Help stimulate the body’s second line of defense by boosting the body’s production of antimicrobial substances 3. Promote overall health by providing vitamins to host
7) Plasma (p.450): Mostly water containing electrolytes, dissolved gases, nutrients, and proteins. Involved in blood clotting a. Serum (p.450): The fluid remaining when clotting factors are removed. b. Includes iron-binding compounds (electrolytes), complement (p458) proteins, and antibodies Formed elements (p.451): Cells and cell fragments suspended in plasma. Produced by “hematopoiesis” in bone the marrow within the hollow cavities of the large bone. 8) Three types of formed elements (p.451):
1. Platelets: Involved in blood clotting
2. Erythrocytes: Most numerous and carries oxygen and carbon dioxide in the blood. 3. Leukocytes (white blood cells): Involved in defending the body against invaders They are divided into granulocytes and agranulocytes
1. Basophils; stain blue: capable of diapedesis (exiting blood vessels) and release inflammatory chemicals. 2. Eosinophils; stain red: Phagocytize pathogens and capable of diapedesis (exiting blood vessels) 3. Neutrophils (polymorphonuclear (PMN’s)); stain lilac: Phagocytize pathogens and capable of diapedesis. Agranulocytes (p.452):
1. Lymphocytes: The smallest leukocyte and most involved in adaptive immunity, natural killers (NK) (p.455) which secretes toxins onto virally infected cells 2. Monocytes: Leave the blood, diapedesis, and mature into macrophages then phagocytize pathogens.
10) An increase of leukocyte (white blood cells) would indicate disease. Bacterial diseases often show increase in leukocytes and neutrophils. An increase of eosinophils would indicate allergies or infection with parasitic worms. An increase in lymphocytes would indicate a viral infection
11) Six stages of phagocytosis (p.453-455):
1. Positive Chemotaxis: The movement of a cell towards chemical stimuli. 2. Adherence: When phagocytes attach to a microorganism membrane 3. Ingestion: A pseudopodia surrounds the microbe then its phagocytized and becomes a phagosome. 4. Maturation: Lysosomes, from the Golgi body, attaches to the phagosome. 5. Killing: Lysosomes releases digestive chemicals into it. It is now called a phagolysosome. The engulfed microbe is digested and dies. 6. Elimination: Sometimes digestion is not complete and the remnants must be removed via exocytosis.
12) Non-phagocytic Killing (p.455):
Eosinophils (p.455): Though they can phagocytize, they typically secrete antimicrobial chemicals a. Eosinophil mitochondrial DNA and proteins form structure that kills some bacteria b. Attack parasitic helminths by attaching to their surface
1. Secrete toxins that weaken or kill the helminth
2. Elevated eosinophils often indicative of a helminth(parasitic worm) infestation Natural Killer (NK) lymphocytes (p.455): Virally infected cells and tumors. An acquired/adaptive immunity a. Elevated eosinophils often indicative of a helminth infestation b. Elevated eosinophils often indicative of a helminth infestation Neutrophils (p.455): Synthesize nets or web of extracellular fibers. Go after bacteria a. Elevated eosinophils often indicative of a helminth infestation b. Elevated eosinophils often indicative of a helminth infestation
13) Four Nonspecific Chemical Defenses Against Pathogens (p.455): 1. Toll-like receptors (TLRs)(p.456): Integral membrane proteins produced by phagocytic cells outside a cell a. Bind pathogen-associated molecular patterns (PAMPs) humans cells don’t have them b. Initiate defensive responses
I. Apoptosis: “Kill it”
II. Secretion of inflammatory mediators
III. Production of stimulants of adaptive immune response
2. NOD proteins (p.456): Another set of receptors for PAMPs that are located inside a cell rather as part of a cell’s cytoplasmic membrane. a. Cytosolic proteins that bind PAMPs
3. Interferons (p.456): Released by host cells to nonspecifically inhibit the spread of viral infections. a. Cause many symptoms associated with viral infections
b. Two types:
I. Types I (alpha and beta): present early in viral infections II. Type II (gamma): appear later in the course of the infection 4. Complement (p.458)(complement system): Set of serum proteins designated numerically according to their order of discovery a. Complement activation results in lysis of the foreign cell causes fever which makes the liver and spleen hold blood.
14) Inflammation (p.461): Nonspecific response to tissue damage from various causes a. Characterized by redness, heat, swelling, and pain
b. Two types:
1. Acute: Develops quickly, is short lived and typically is beneficial
Important in the second line of defense:
I. Dilation and increased permeability of the blood vessels
II. Migration of phagocytes
III. Tissue repair
2. Long-lasting (chronic): causes damage, even death, to tissues resulting in disease.
Fever (p.463): A body temperature over 37°C. It results when pyrogens trigger the hypothalamus.to increase the body’s core temperature
Types of pyrogens (a fever-producing chemical)(p.464):
1. Bacterial toxins
2. Cytoplasmic contents of bacteria released by lysis
3. Antibody-antigen complexes
4. Phagocytized bacteria
B lymphocytes (B Cells) and Antibodies
T lymphocytes (T Cells)
Where they Form
Red bone marrow
Red bone marrow
Where they Mature
Red bone marrow
Where they Concentrate
Spleen, MALT, germinal centers of lymph nodes, small amounts in blood Circulate in the lymph and blood and migrate to the lymph nodes, spleen, and Peyer’s patches How they Work
Mount an attack against extracellular pathogens by secreting antibodies and soluble proteins Mount an attack against intracellular pathogens such as viruses replicating in a cell. Cell mediated do not use antibodies types of adaptive immune response
Humoral, for extracellular pathogens
Cell-mediated, for , intracellular pathogens
16) (p.474) a spleen acts primarily as a blood filter. It removes bacteria, viruses, toxins, and foreign matter from blood. It also cleanses the blood of old + damaged blood cells, stores blood platelets and recycles/stores iron and other minerals. The spleen also synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation. Surgical removal causes:
1. modest increases in circulating white blood cells and platelets 2. Diminished responsiveness to some vaccines
3. Increased susceptibility to infection by bacteria and protozoa; in particular, there is an increased risk of sepsis from polysaccharide encapsulated bacteria. 17) Mucosa-associated lymphatic tissue (MALT)(p.474): Contains most of the bodies lymphocytes. The appendix and Peyer’s patches in the intestinal wall are a part of MALT. It is the diffusion system of small concentrations of lymphoid tissue found in various sites of the body, such as the gastrointestinal tract, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and deliver it to the lymphoid tissue.
18) Adaptive Immunity, two types (p.471):
1. Humoral response immunity (antibody immunity) (p.471): takes down pathogens floating in the blood. Used by B-Cells to fight exogenous (originating outside an organism or system) antigens. extracellular
2. In the Cell-Mediated response: Kills cells that have become infected with the pathogen. Used by T-Cells to fight intracellular pathogens and abnormal body cells. intracellular
19) Antigen (p.474): A molecule that triggers a specific immune response. It’s the protein of bacteria, fungi, protozoa or virus. Epitope (antigenic
determinants) (p.475): A 3D shape of a region of an antigen that is recognized by the immune system
20) Three types of antigen particles (p.474)
1. Exogenous Antigens: Originate from microbes located outside the body’s cells. Include toxins and other secretions and components of microbial cell wall, membranes, flagella, and pili. Antigenic Pathogens 2. Endogenous Antigens: Produced by intracellular microbes and are typically incorporated into a host cytoplasmic membrane. Protozoa, fungi, bacteria, and viruses that reproduce inside body’s cells 3. Autoantigens: Components of normal body cells. The tolerance of these cells with Autoantigens is called (self-tolerance) Stimulates autoantibodies. “kills self” think autoimmune
21) (p.476) Yes, they are specific. No, they can only recognize one epitope.
22) Antibodies (p.476): Are free immunoglobulins. They are secreted and lack bulk. Consist of 4 polypeptide chains, 2 heavy chains and 2 light chains, held together by disulfide bonds.
23) Antibody function with invading pathogens (p.477):
1. Activation of complement and inflammation:
2. Neutralization: Neutralize a toxin by binding to a critical portion of the toxin. Can block adhesion molecules on the surface of bacterium or virus, neutralizing the pathogens virulence. 3. Opsonization: Changing the surface of the antigen so as to enhance phagocytosis. 4. Killing by oxidation: Antibodies catalyze production of hydrogen peroxide, ozone, and other potent oxidants that kill bacteria. 5. Agglutination: The clumping of cells such as bacteria or red blood cells in the presence of an antibody. The antibody or other molecule binds multiple particles and joins them, creating a large complex 6. Antibody-dependent cellular cytotoxicity (ADCC):
24) Opsonization (p.477): Changing the surface of the antigen so as to enhance phagocytosis.
Can be secreted
Don’t recognize epitopes directly and only bind epitopes associated with a MHC (p.485) protein. Primarily act against cells that harbor intracellular pathogens.
26) Three types of T lymphocytes (p.481): Based on surface glycoproteins and characteristic functions.(p.482) 1. Cytotoxic: Directly kills other cells
2. Helper T: Helps regulate the activities of B cells and cytotoxic T cells 3. Regulatory T: Represses adaptive immune responses and prevent autoimmune disease.
27) Cytokine (p.484): Soluble regulatory proteins that act as intercellular signals a. Cytokines secreted by various leukocytes
b. Cytokine network is a complex web of signals among all the cells of the immune system
28) Types of Immunity (p.496):
1. Naturally acquired: Response against antigens entering the body naturally. 2. Artificially acquired: Response against antigens entering the body via a vector A. Active: When the body produces its own antibodies
B. Passive: Receive antibodies from a source outside the body
29) Passive Immunotherapy (p.509): Administration of antiserum containing preformed antibodies a. Provides immediate protection against recent infection or ongoing disease b. Antisera have several limitations:
1. Contain antibodies against many antigens
2. Can trigger allergic reactions called serum sickness
3. Viral pathogens may contaminate antisera
4. Antibodies of antisera are degraded relatively quickly
c. Limitations are overcome through development of hybridomas (hybrid cell lines)
30) Active Immunization three Vaccine types (p.504):
1. Attenuated (live) vaccines: Use pathogens with reduced virulence a. Can result in mild infections
b. Active microbes stimulate a strong immune response
c. Can provide contact immunity
d. Modified microbes may retain enough residual virulence to cause disease 2. Inactivated (killed) vaccines two types: Both safer than live vaccines I. Whole-agent vaccines.
II. Subunit vaccines
-Microbes don’t provide many antigenic molecules to stimulate the immune response -Often contain adjuvants: Chemicals added to increase effective antigenicity 3. Toxoid vaccines: Chemically or thermally modified toxins used to stimulate immunity a. Useful for some bacterial diseases
b. Stimulate antibody-mediated immunity
c. Require multiple doses because they possess few antigenic determinants 31)
(p.505) can make improved vaccines by selectively deleting virulence genes from pathogens, producing a microbe that won’t revert to a virulent pathogen.
32) We can grow more vaccine in chicken eggs than in issue and the pathogen becomes more adapt than humans. Thus, making the pathogen less viral to us. Eggs are typically sterile (p.505) 33) Problems associated with immunization
1. Mild toxicity most common
2. Risk of anaphylactic shock
3. Residual virulence from attenuated viruses
4. Allegations that certain vaccines cause autism, diabetes, and asthma Research has not substantiated these allegations