Microbiology Unit 5
Terms
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- Resistance
- The ability to ward off disease
- Nonspecific resistance - 1st line
- intact skin, mucous membranes, normal microbiota
- Nonspecific resistance - 2nd line
- phagocytic white cells, inflammation, fever, antimicrobial substances
- Specific resistance - 3rd line
- B cells and T cells, antibodies
- Ciliary escalator
- keeps mucus blanket moving toward the throat
- Sebum
- oily substance containing fatty acids, inhibits bacteria
- Lyzozome
-
1. Enzyme capable of breaking down cell walls of gram-positive bacteria
2. Found in tears, saliva, nasal secretions, perspiration - Phagocytosis
- ingestion of microorganism by a cell
- phagocytes
- white blood cells or derivatives of white blood cells
- Plasma
- Contains formed elements (cell and cell fragments)
- Leukocytosis
- Increase in white blood cells to combat microbes
- Granulocytes
- -Type of leukocyte
- Neutrophil
-
Type of granulocyte
Most important phagocyte
Active in initial stage of infection - Basophil
-
Role not clear
Release substances such as histamine - Eosinophils
-
Somewhat phagocytic
ability to leave blood
Produce toxic proteins against certain parasites - Enlarged monocyte
- Become wandering macrophage and fixed macrophage
- Monocyte
- predominate as infection subsides
- Lymphocyte
-
T cells and B cells
Occur in lymphoid tissues of lymphatic system - tonsils, spleen, thymus, red bone marrow, blood - Chemotaxis
- Chemical attraction of phagocytes to microorganisms
- Opsonizations
-
coating microbe w/plasma proteins
facilitates adherence to cell - Phagocytosis steps
-
1. Chemotaxis
2. Ingestion
3. MO surrounded by sac - Pseudopods
-
engulf microorganism
extensions of plasma membrane of phagocyte - Microbial Evasion
-
Bacteria may inhibit adherence
May be ingested but not killed
Microbes may survive insiode phagocyte - Inflammation
-
Bodily response to cell damage
Characterized by:
1. Redness
2. Heat
3. Swelling
4. Pain - Vasodilation
-
Dilation of blood vessels
Caused by release of histamine, kinins, and prostaglandins - Histamine
- released in direct respone to the injury of cells that contain it
- Kinin
-
present in blood plasma
cause vasodilation - Prostaglandins
- intensify effects of histamine and kininds
- Blood clots and site
- may form to prevent microbe from spreading
- Margination
- Phagocytes begin to stick to the inner surface of the endothelium
- Emigration
- Phagocytes begin to squeeze between the endothelial cells of blood vessel
- Pus
- Accumulation of damage tissue and dead microbes, granulocytes, and macrophages
- Stroma
- supporting connecting tissue
- Parenchyma
- functioning part of tissue
- Stromal repair
-
Done by fibroblasts
Produces scar tissue - Fever
- induced by bacterial endotoxins and interleukin-1
- Chill
- Rising body temperature
- Crisis (sweating)
- Body's temp is falling
- Interferon
-
Antiviral protein produced in response to viral infection
Host specific but not virus specific
Effective for only short periods - Types of interferon
-
Alpha, beta, gamma
Also recombant - Complement
-
Defensive system of 30 proteins
In blood serum and tissues - Anti-viral Proteins
- Enzymes that disrupt various stages of viral multiplication
- Gamma IFN
-
Produced by lymphocytes
Induces neutrophils and macrophages to kill bacteria by phagocytosis - Antigens
- Proteins, nucleoproteins, lipoproteins
- Immunity
- Ability of the body to specifically counteract foreign organisms or antigens
- Naturally acquired active immunity
-
Person is exposed to antigens in course of daily life
measles, chicken pox - Naturally acquired passive immunity
- Transfer of antibodies from mother to infant
- Artifically acquired active immunity
- Vaccination
- Artifically acquired passive immunity
- Introduction of antibodies (rather than antigens) into the body
- Antiserum
- Serum containing antibodies
- Humoral immunity
-
Production of antibodies that act against foreign organisms and substances
B Cells responsible for production of antibodies
Defends against bacteria, bacterial toxins - Cell mediated immunity
-
Depends on T Cells
Does not involve antibody production
Most effective against bacteria and viruses w/in phagocytic cells, fungi, protozoa, helmiths
Primary responder to transplated tissue
Defends against cancer - Antigenic determinant groups
- Specific regions on surface of antigen where antibodies are formed
- Haptens
- Small compounds that act as carrier molecules for antigens
- Antigen binding site
-
Sites that bind to antigenic determinants
At least two for each antibody - Antibody monomer
- Four polypeptide chains - two heavy, two light
- B cells
-
Mature migrate to lymphoid organs
recognizes antigen w/antigen receptors - Activated B cells
- Produce clone of plasma cells and memory cells
- Plasma cells
- Secrete antibody
- Memory cells
- Recognizes pathogens from previous encounters
- IgG antibodies
- Inactivate viruses and neutralize bacterial toxins
- Antigen-antibody complexes
-
involves IgG and IgM antibodies to fix complement
Results in lysis of bacterial cell - Antibody titer
- Amount of antibody in serum
- Primary response
- Appearance of IgM then IgG
- Secondary response
- high antibody titer, primarily IgG
- Edward Jenner
-
Developed modern practice of vaccination
Innoculation w/cowpox virus - Attenuated whole-agent vaccine
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Living, weakened microbes
More closely mimic actual infection
Polio vaccine, MMR, TB, Rickettsia
Not recommended to people w/compromised immune systems - Inactivated whole-agent vaccine
-
Use killed microbes
Influenza, polio, pneumonia, cholera, pertussis, typhoid - Toxoids
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Inactivated toxins
Directed at toxins produced by pathogen
Tetanus and diptheria - Subunit vaccines
-
Use antigenic fragments of microorganism to best stimulate immune response
Hepatitis B, Cholera, Streptococcus - Conjugated vaccine
-
Combine desired antigen w/protein to boost immune system
Hib vaccine - Nucleic Acid vaccine (DNA vaccine)
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Recipient makes antigenic proteins
Do not need to be grown in cells or animals
Influenza A - Where to grown viruses for vaccines
- Animals, cell cultures, chick embryos
- Superantigen
- nonspecific antigens and indiscrimantely acitive T cell receptors at once
- Hypersensitivity
- Antigenic response beyond that which is considered normal
- Type I (Anaphylactic) reaction
-
Occur wi/in 2 to 30 minutes of exposure
Production of IgE antibodies that bind to mast cells and basophils
Target cell release chimical mediators (kinin, histamine, leukotrienes) - Anaphylaxis
-
Reactions caused when certain antigens combine w/IgE antibodies
Systemic-shock, breathing difficulties
Localized-hay fever, asthma, hives - Desensitization
- Repeated injections of antigen, leads to formation of IgG antibodies
- Blood type
- Determined by presence or absence of two carbohydrates
- AB
-
No anti-A or anti-B antibodies
Universal recipient - can get A, B, AB, O types - B
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Anti-A antibodies
Can have B, O blood - A
-
Anti-B antibodies
Can have A, O blood - O
-
Anti A and Anti-B Antibodies
Can have O blood, universal donor - Rh factor
-
Surface antigen
85% population are Rh+ - Rh+ blood type
- Can receive Rh+ or Rh-
- Rh- blood type
-
If receives Rh+, donor's RBC stimulate anti-Rh antibodies
If receives subsequent Rh+, hemolytic reaction - Hemolytic disease of newborn
-
Rh- carries Rh+ fetus, anti-Rh antibodies
Can be prevented by mother receiving anti-Rh antibodies (Rhogam) - Autoimmunity
- Loss of self-tolerance
- Type I Autoimmunity
-
Antibodies that attack self
Hepatitis C - autoimmune hepatitis - Type II (Cytotoxic) Autoimmunity
-
Antibody reactions to cell-surface antigens
Graves' disease, myasthenia gravis - Type III (Immune complex) autoimmunity
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Antibodies directed at components of own cells
Lupus, Rheumatoid arthritis - Type IV (Cell-Mediated) Autoimmunity
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T cells
MS, Hashimoto's Thyroiditis - Histocompatability antigens
-
located on cell surfaces
Express genetic differences among individuals - Transplant compatability
-
Match HLA and ABO antigens
If recognized as foreign, may be lysed by T cells and attacked by macrophages - Privileged transplation site
-
Antibodies do not circulate
Cornea - Privileged transplantation tissue
-
Does not stimulate immune rejection
Pig heart - Autograft
- One's own tissue grafted to another part of body
- Isograft
- Identical twin grafting
- Allografts
- Grafts between people who are not identical twins
- Xenotransplatation products
- Tissues or organs from animals
- Cyclosporine
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Immunosuppressant drug
Inhibits secretion of IL-2