micro biology
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Created by:
kevin34669 on November 5, 2010
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171 terms
Terms | Definitions |
|---|---|
 Pathogenicity | The ability to cause disease |
| Virulence | The extent of pathogenicity |
| ID50: | Infectious dose for 50% of the test population |
| LD50 | Lethal dose (of a toxin) for 50% of the test population |
| Portal of entry - Skin | ID50 : 10-50* endospores, "woolsorters disease" |
| Portal of entry - Inhalation | 10,000-20,000, * endospores, pulmonary anthrax |
| Portal of entry | Botulinum, Shiga toxin, some Shigella,some E. coli from plasmid |
| Adhesins/ligands | bind to receptors on host cells : Form biofilms for transportation, nutrient transport and protection. |
| Glycocalyx: | Streptococcus mutans, others |
| Fimbriae: | Escherichia coli, many others |
| M protein: | Streptococcus pyogenes, toxic : resists phagocytosis |
| Capsules | Prevent phagocytosis and immune recognition. |
| Opa protein | inhibits T helper cells Neisseria gonorrhoeae |
| Mycolic acid | (waxy lipid) resists digestion by macrophages Mycobacterium tuberculosis |
| Coagulase | Coagulates fibrinogen, prevents clots from containing pathogen |
| Kinases | Digest fibrin clots, allowing spreading. |
| Hyaluronidase: | Hydrolyzes hyaluronic acid, increasing host cell penetration |
| Collagenase | Hydrolyzes collagen, reducing host cell interconnectivity |
| IgA proteases | Destroy IgA antibodies, adversely affecting host defense |
| Toxin | Substance that contributes to pathogenicity eg. endo or exotoxins |
| Toxigenicity | Ability to produce a toxin |
| Toxemia | Presence of toxin in the host's blood |
| Toxoid | Inactivated toxin used in a vaccine eg. tetanus vaccine |
| Antitoxin | Antibodies against a specific toxin, eg. rattlesnake antivenin |
| Membrane-Disrupting Toxins | Lyse host's cell membranes by; Making protein channels in the plasma membrane |
| Membrane-Disrupting Toxins | LeukocidinsHemolysins Streptolysins Disrupting phospholipid bilayer; damages host cell membrane. |
| Superantigens | Cause an intense immune response due to release of cytokines from host cells |
| Corynebacterium diphtheriae | A-B* toxin |
| Streptococcus pyogenes | Membrane-disrupting erythrogenic |
| Clostridium botulinum | neurotoxin |
| Vibrio cholerae | enterotoxin |
| Vibrio cholerae | Superantigen |
| LAL Assay, horseshoe crab blood | Limulus amoebocyte lysate assay for endotoxins |
| Pathogenic Properties of Fungi | waste products : Chronic infections provoke an allergic response - |
| Tichothecene toxins | inhibit protein synthesis, weaponized : Fusarium |
| Proteases | Candida, Trichophyton |
| Capsule | prevents phagocytosis Cryptococcus |
| Mycotoxins* | Neurotoxins: Phalloidin, amanitin Amanita mushroom, common lawn mushroom |
| protozoa | Use host nutrients. Waste products may cause symptoms. Avoid host defenses by Growing in phagocytes Cell membrane alterations among generations, prevent immune recognition. |
| Pathogenic Properties of Algae | Paralytic shellfish poisoning, red tide aerosol Dinoflagellates Saxitoxin |
| Portals of Exit, to infect new hosts | Respiratory tract Coughing and sneezing Gastrointestinal tract Feces and saliva Genitourinary tract Urine, urinary tract and vaginal secretions via intimate contact Skin, eg. many viruses, bacterial infections. Blood Biting arthropods and syringes |
| Susceptibility | Lack of resistance to a disease |
| Immunity: | Ability to ward off disease |
| Innate immunity | Defenses against any pathogen, nonspecific, short lived, eg. skin, mucous |
| Adaptive immunity | Immunity, resistance to a specific pathogen, precise, long lasting, eg. T and B cells, takes time to develop. |
| Physical, Innate Factors | Epidermis - consists of tightly packed cells.(skin) Keratin - a protective protein, main component in hair and fingernails. |
| Physical, Innate Factors | Mucous membranes Mucus: Traps microbes Ciliary escalator: Microbes trapped in mucus are transported away from the lungs phlegm |
| Physical Factors | Lacrimal apparatus: Washes eye, tears Saliva: Washes microbes off Urine: Flows out Vaginal secretions: Flow out |
| Chemical Factors | Fungistatic fatty acid in sebum, oily skin Low pH (3-5) of skin Lysozyme in perspiration, tears, saliva, and urine Low pH (1.2-3.0) of gastric juice Low pH (3-5) of vaginal secretions |
| Normal microbiota | compete with pathogens or alter the environment |
| Commensal microbiota | One organism (microbe) benefits and the other (host) is unharmed |
| Neutrophils Macrophages | Phagocytosis |
| Basophiles | Histamine; triggers inflammation |
| Eosinophils | Kill parasites |
| Formed Elements in Blood | Monocytes, Dendritic, Natural killer cells -Destroy targeted cells, including cancerous tissue |
| Inflammation | Acute-phase proteins : Vasodilation :(edema) |
| Fever | Abnormally high body temperature Hypothalamus normally set at 37°C |
| fever - Advantages | Increases transferrins to keep iron from pathogen Increases IL-1 activity Produces Interferons |
| fever - Disadvantages | Tachycardia Acidosis Dehydration 44-46°C fatal |
| The Complement System | Serum proteins , Activated by Antigen-antibody reaction C3b causes opsonization |
| Effects of Complement Activation | Opsonization or immune adherence: Enhanced phagocytosis Membrane attack complex: Cytolysis Attract phagocytes |
| Evade Complement | Capsules prevent C activation Surface lipid-carbohydrates prevent membrane attack complex (MAC) formation Enzymatic digestion of C5a |
| Interferons (IFNs) | IFN- and IFN-: Cause cells to produce antiviral proteins that inhibit viral replication Gamma IFN: Causes neutrophils and macrophages to phagocytize bacteria |
| Innate immunity | Defenses against any pathogen |
| Adaptive immunity | Induced resistance to a specific pathogen |
| T and B cells | develop from stem cells |
| Humoral immunity, Antibodies | B cells mature in the bone marrow |
| Cellular immunity | Due to T cells T cells mature in the thymus |
| Antigen (Ag): | A substance that causes the body to produce specific antibodies or sensitized T cells |
| Hapten: | Antigen is combined with carrier molecules for transport to Immune cells |
| Proteins, synonym | immunoglobulins |
| antigen-binding sites | determines valence; |
| IgG Antibodies | Monomer Cross placenta Enhance phagocytosis; neutralize toxins and viruses; protects fetus and newborn |
| IgM Antibodies | Pentamer, 5 linked antbodies Agglutinates microbes; first Ab produced in response to infection |
| IgA Antibodies | Dimer Mucosal protection Focus for "allergy shots |
| IgD Antibodies | Monomer On B cells, initiate immune response |
| IgE Antibodies | Monomer On mast cells* Allergic reactions; lysis of parasitic worms *Histamine production, helps to induce inflammatory response |
| Agglutination | clumping |
| Opsonization | inducing phagocytosis with antibody "markers" |
| T helper cells | boost immune response |
| T Cytotoxic Cells, CTL's | Induce apoptosis (cell death) in target cell CTL releases perforin(induces lysis) and granzymes, a protease |
| Apoptosis | Cell membrane collapses |
| T Regulatory Cells, aka Supressor T's | Suppress T cells from reacting against "self" cells. Failure leads to autoimmune illnesses |
| Antigen-Presenting Cells, APC's | Digest antigen or AG Ag fragments on APC's surface with MHC* *Major histocompatibility complex, markers that identify your cells. |
| Activated Macrophages | hunt AG bearing pathogens |
| Natural Killer (NK) Cells | Granular leukocytes destroy cells that don't express MHC Kill virus-infected and tumor cells Attack parasites |
| Cytokines | Chemical messengers used to induce localized immune responses, inflammation. Overproduction leads to cytokine storm, a dangerous "feedback loop" causes excessive immune reaction, dangerous and can be lethal |
| Antibody titer | is the amount of Ab in serum |
| Primary response | occurs after initial contact with Ag(antigen) |
| Secondary (memory or anamnestic) response | occurs after second exposure, raising Ab titer. |
| anaphylaxis | an excessive systemic inflammatory reaction |
| Serology | The study of reactions between antibodies and antigens |
| Antiserum | The generic term for blood serum which contains Ab |
| Globulins | Serum proteins, general term |
| Immunoglobulins | Antibodies |
| Gamma globulin | Mixed serum fraction containing various Ab's |
| Inactivated | "no reproductive ability, dead",whole-agent vaccines Salk polio |
| Toxoids | "damaged", is antigenic but ineffective. Tetanus |
| Subunit vaccines | "parts" of the virus Acellular pertussis Recombinant hepatitis B |
| Nucleic acid (DNA) vaccines | West Nile (for horses) |
| rDNA techniques | In plants |
| Adjuvants | non specific but enhance secondary immune response. Use is fading. Deliver in combination |
| Sensitivity | Probability (%) that the test is reactive if the specimen is a true positive |
| Specificity | Probability that a positive test will not be reactive if a specimen is a true negative |
| Hybridoma | : "Immortal" cancerous B cell fused with an antibody-producing normal B cell, produces |
| Monoclonal antibodies | Very pure and specific, can be harvested in quantity. |
| Hemagglutination | involves agglutination of RBCs Some viruses agglutinate RBCs in vitro (outside of living organism) |
| Enzyme-Linked Immunosorbent Assay | Also called ELISA Enzyme linked to Ab is the indicator, enzyme activity results in detectable change in vitro |
| Precipitation | Soluble antigens |
| Agglutination | Particulate antigens |
| Hemagglutination | Agglutination of RBCs |
| Neutralization | Ab Inactivates toxin or virus |
| Fluorescent-antibody technique | : Antibodies linked to fluorescent dye ELISA |
| Type I (Anaphylactic) Reactions | IgE attached to mast cells and basophils Antigen binds to two adjacent IgE Mast cells and basophils undergo degranulation, which release excessive immune mediators: Histamine Leukotrienes Prostaglandin |
| Systemic anaphylaxis | May result in circulatory collapse, suffocation and death |
| Localized anaphylaxis | Hives, hay fever, and asthma |
| Preventing Anaphylaxis | Desensitizating injections of Ag "allergy shots" Cause IgG blocking Ab |
| Type II (Cytotoxic) Reactions | Complement activation causes cell lysis or damage by macrophages |
| Type III (Immune Complex) Reactions | IgG antibodies and antigens form immune complexes that lodge in basement membranes(zones where tissues are joined |
| Type IV (Cell-Mediated) Reactions | Delayed-type hypersensitivities due to T cells and MHC, Ig not involved, eg. Crohns, multiple sclerosis, rheumatoid arthritis. Cytokines attract macrophages and TC cells: Initiate tissue damage Takes a few days to manifest |
| Autoimmune Diseases (body attacks "self") | Clonal deletion (deactivated "self" T and B cells)during fetal development usually ensures self-tolerance. Autoimmunity is loss of self-tolerance |
| Cytotoxic | Antibodies react with cell-surface antigens Graves' disease (thyroid), diabetes (pancreas) |
| Immune complex | IgM, IgG, complement immune complexes deposit in tissues Systemic lupus erythematosus, SLE, connective tissues |
| Cell-mediated | Mediated by T cell cytokines Psoriasis(skin accumuation, various types) poorly understood |
| Histocompatibility antigens | Self antigens on cell surfaces. |
| Major histocompatibility complex (MHC): | Genes encoding histocompatibility antigens |
| Human leukocyte antigen (HLA) complex | MHC genes used in human immune system cells. |
| Reactions to Transplantation | may be attacked by T cells, macrophages, and complement-fixing antibodies. privileged sites do not cause immune response. |
| Stem cells | may allow therapeutic cloning to avoid rejection, bone marrow transpant Embryonic stem cells are pluripotent(can differentiate into other cell types. Adult stem cells have been differentiated to form specific cells |
| Autograft: | Use of one's own tissue |
| Isograft: | Use of identical twin's tissue |
| Allograft | Use of tissue from another person |
| Xenotransplantation product | Use of nonhuman tissue, eg heart valves(pigs) |
| Hyperacute rejection | Response to nonhuman Ag, C' and cytokine storm can lead to system failure. Transplanted organ must be removed immediately. |
| Graft-versus-host disease (GVH) | can result from transplanted bone marrow (sometimes used to treat leukemias) that contains immunocompetent cells from donor, donor cells attack recipient. |
| Immunosuppression | Prevents an immune response , suppress IL-2, inhibits T cell and B cell reproduction |
| TNF or tumor necrosis factor | a cytokine inducing apoptosis |
| Immunotherapy | Treatment of cancer using immunologic methods |
| Immunotoxins | link poisons with a monoclonal antibody directed at a tumor antigen |
| Congenital Immunodeficiencie | Due to defective or missing genes |
| Acquired Immunodeficiencie | Develop during an individual's life Due to drugs, cancers, and infections Combination of both; increased probability |
| Origin of AIDS | Crossed the species barrier into humans in Africa in the 1930s : 1959 in Congo |
| HIV Transmission | Infected body fluids transmit HIV, including breast milk |
| Highly active antiretroviral therapy (AIDS"cocktail") | Combinations of nucleoside reverse transcriptase inhibitors and other drugs, Highly effective, expensive |
| Chemotherapy | The use of drugs to treat a disease |
| Antimicrobial drugs | Interfere with the growth of microbes within a host |
| Antibiotic | A substance produced by a microbe that, in small amounts, inhibits another microbe |
| Selective toxicity | A drug that kills harmful microbes without damaging the host |
| Spectrum of Antimicrobial Activity | Broad spectrum, kills many types, eg. gram neg. Narrow spectrum, kills a few precise pathogens Superinfection (an illness promptly follows another illness or invades while original pathogen is still present), eg. Quinolones |
| Bactericidal | Kill microbes directly |
| Bacteriostatic | Prevent microbes from growing |
| Inhibitors of Cell Wall Synthesis | Penicillin group Natural penicillins Semisynthetic penicillins Extended-spectrum penicillins |
| b-Lactam Antibiotics | , disrupt critical cell wall component. Penicillin |
| Inhibitors of Cell Wall Synthesis | Vancomycin Glycopeptide Important "last line" against antibiotic-resistant S. aureus, now overused, less useful |
| Antimycobacterial (eg. tuberculosis)antibiotics | Isoniazid (INH) Inhibits mycolic acid synthesis Ethambutol Inhibits incorporation of mycolic acid |
| Sulfonamides (sulfa drugs | Inhibit folic acid synthesis Broad spectrum |
| Antifungal Drugs | Inhibition of ergosterol (part of cell membrane) synthesis Inhibition of outer cell wall synthesis |
| Antiviral Drugs | Nucleoside and nucleotides |
| Protease inhibitors | Indinavir: HIV |
| Integrase inhibitors | HIV Inhibit viral attachment Zanamivir: Influenza Block CCR5: HIV Inhibit viral uncoating Amantadine: Influenza |
| Interferons | Prevent spread of viruses to new cells Alpha interferon: Viral hepatitis |
| Antiprotozoan Drugs | Chloroquine Inhibits DNA synthesis Malaria, resistance is getting common Diiodohydroxyquin Unknown mode of action Amoebic diseases |
| Antihelminthic (some parasites)Drugs | Niclosamide - tape worms Praziquantel - flat worms |
| MIC | Minimal inhibitory concentration |
| MBC | Minimal bactericidal concentration |
| Antibiogram | for direct sample testing ( smear of dog with tonsilitis) |
| Antibiotic Resistance | Enzymatic destruction of drug Prevention of penetration of drug Alteration of drug's target site Rapid ejection of the drug Resistance genes are often on plasmids or transposons that can be transferred between bacteria |
| Antibiotic Resistance due to Misuse | outdated or weakened - inappropriate conditions - Failing complete the prescribed regimen Using someone else's leftover prescription |
| Synergism | occurs when the effect of two drugs together is greater than the effect of either alone |
| Antagonism | occurs when the effect of two drugs together is less than the effect of either alone |
| Therapeutic index | risk vs. benefit |
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