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Specific Defenses of the Host Microbiology 2314
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Innate Resistance An individual’s genetically predetermined resistance to certain diseases We are born with this resistance. Ex. Resistance to AIDS due to a Delta-32 gene
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Humans Have Innate Resistance to a Number of Different Things Bacteria Viruses Fungi Protozoa Insect Venom Transplanted Tissue Cancer Cells Diseases
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Individual Resistance is Affected By Gender Age Nutritional Status General Health
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Resistance Leads to Immunity The ability of the body to specifically counteract foreign organisms or substances called antigens. Results from the production of specialized lymphocytes and antibodies (proteins)
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Serology Looks at reactions between antibodies and antigens A specialized branch of microbiology. Uses serum samples
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Remember! Antigens provoke an immune response. Antibodies are produced to respond to antigens. Antigens Antibodies Protection
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Immunity Obtained After Birth
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Naturally Acquired Active Immunity Immunity Resulting from Infection May be Long Term
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Naturally Acquired Passive Immunity Mother to Fetus Transplacental Transfer Colostrum Few Months Duration
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Artificially Acquired Active Immunity Immunity Resulting from Injection (Vaccination) Attenuated Vaccines Inactivated Vaccines Killed Vaccines Toxoid Vaccines
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Artificially Acquired Passive Immunity Humoral Antibodies Acquired By Injection Lasts for Few Weeks Antisera
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Gel Electrophoresis is Used to Check for Antibodies Albumen Alpha Beta Gamma Globulins
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By taking advantage of distinct physical characteristics of different polypeptide species such as size, electrical charge, and shape, a complex mixture of proteins can be resolved electrophoretically by applying the sample to a gel matrix in the presence of an electric current.
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How Does This Work? A charged protein will migrate in an electric field relative to its net charge. However, as the molecule migrates through the gel matrix in response to the electric current, its mobility will be retarded as a function of the size and shape of the protein by the sieving effect of the gel matrix.
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Antibodies are found in the gamma fraction of the serum and are termed serum globulin or gamma globulin
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Albumen Alpha Beta Gamma Normal Values
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Total protein: 6.4 to 8.3 g/dL Albumin: 3.5 to 5.0 g/dL Alpha-1 globulin: 0.1 to 0.3 g/dL Alpha-2 globulin: 0.6 to 1.0 g/dL Beta globulin: 0.7 to 1.2 g/dL Gamma globulin: 0.7 to 1.6 g/dL
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Decreased total protein may indicate: Malnutrition Nephrotic syndrome Gastrointestinal protein-losing enteropathy Increased alpha-1 globulin proteins may indicate: Chronic inflammatory disease (for example, rheumatoid arthritis, SLE) Acute inflammatory disease Malignancy Decreased alpha-1 globulin proteins may indicate: Alpha-1 antitrypsin deficiency
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Increased alpha-2 globulin proteins may indicate: Acute inflammation Chronic inflammation Decreased alpha-2 globulin proteins may indicate: Hemolysis Increased beta globulin proteins may indicate: Hyperlipoproteinemia (for example, familial hypercholesterolemia) Estrogen therapy Decreased beta globulin proteins may indicate: Congenital coagulation disorder Consumptive coagulopathy Disseminated intravascular coagulation
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Increased gamma globulin proteins may indicate: Multiple myeloma Chronic inflammatory disease (e.g., rheumatoid arthritis, SLE) Hyperimmunization Acute infection Waldenstrom's macroglobulinemia Chronic liver disease
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Normal Significantly Increased Gamma Globulin
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Albumen Albumin is synthesized by the liver using dietary protein. Its presence in the plasma creates an osmotic force that maintains fluid volume within the vascular space. A very strong predictor of health; low albumin is a sign of poor health and a predictor of a bad outcome.
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Horizontal Ridges in Fingernails is a Sign of Low Albumen
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Low Albumen Can Indicate Dehydration Hypothyroidism Chronic debilitating diseases Malnutrition - Protein deficiency Dilution by excess H2O (drinking too much water, which is termed “polydipsia,” or excess administration of IV fluids) Kidney losses (Nephrotic Syndrome) Protein losing-enteropathy (protein is lost from the gastrointestinal tract during diarrhea) Skin losses (burns, exfoliative dermatitis) Liver dysfunction (the body is not synthesizing enough albumin and indicates very poor liver function)
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Humoral and Cell Mediated Our Immunity is Expressed Via Two Different Mechanisms
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Humoral Immunity = Antibodies Found in Body Fluids Involves Specialized Lymphocytes Called B Cells that Produce Antibodies Produced in Response to a Specific Antigen Defend the Body Against Bacteria, Viruses, and Toxins in Blood Plasma and Lymph (Extracellular Presence)
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An Antibody Molecule is shaped like the Letter Y and has TWO Identical ANTIGEN BINDING SITES that precisely fit the shape of a ParticularAntigen. Lock and Key. These sites allow each Antibody to bind to TWO Antigens.
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By binding to two antigens, antibodies make antigens clump together. (AGGLUTINATION)
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The clumped Antigens are not active. Macrophages ENGULF and DESTROY the Clumped Antigens..
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Bone Marrow Stem Cells (Plasma Cells) Give Rise to B-Cells Liver in Fetus Does Same B-Cells Migrate to Lymph Nodes Recognition Process Occurs In Which a Mature B-Cell will Recognize an Antigen with Antigen Receptors and produce antibodies.
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Cell-Mediated Immunity Involves Specialized Lymphocytes Called T-Cells arising from the Thymus Gland No Antibody Production is Involved Protect the Body from – Intracellular bacteria and viruses –Multi-cellular parasites –Transplanted tissue –Cancer cells
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T-Cells Attacking a Cancer Cell
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Review and Remember Antigen – (Also Called an Immunogen) A chemical substance that causes the body to produce either specific antibodies or sensitized T-cells. Are foreign substances Can be microbial or non-microbial
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Non-Microbial Antigens Pollen Egg White Transplanted Tissue Peanut Butter
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Most Antigens are Components of Invading Microbes Proteins - Nucleoproteins - Lipoproteins - Glycoproteins Large Polysaccharides - Cell Walls - Capsules - Flagella - Toxins
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The Nature of Antibodies An antibody (also called an Immunoglobulin) is a protein produced by B cells in response to the presence of an antigen and is capable of combining specifically with that antigen.
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Antibody Structure Monomer Single Bivalent Antibody Four Polypeptide Chains Two Heavy Chains Two Light Chains Variable Region Constant Region Y or T shaped
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The Variable Region forms the tips of the monomer. The constant regions form the Base and the Stem Region The Stem Region can Attach a Host Cell or Complement (The Stem is called Fc as it is a fragment that crystallizes when cold)
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Immunoglobulin Classes IgG / Monomer IgM / Pentamer IgA / Dimer IgD / Monomer IgE / Monomer
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IgG Prevalent / 75% - 80% in Body Fluids (Serum) Provide Naturally Acquired Passive Immunity Neutralize Toxins, Fight Bacteria and Viruses Participate in Complement Fixation Enhance Phagocytosis Cross Blood Vessels Cross Placenta (Unique to IgG) Y
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IgM Five Monomers, Largest Found in Blood and Lymph Involved in Agglutination in Blood Typing Participate in Complement Fixation Compose 5-10% Can’t Move Freely / Stay in Blood Vessels First Responder to Infection Short Lived Y Y Y Y Y
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IgA Dimers / Compose 10-15% Protect Mucosal Surfaces from Pathogens / Saliva, Tears, Blood Repel Respiratory Infections Present Colostrums Protect Infants / GI Infections A small number of people do not make IgA antibodies. Y Y
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IgD Monomer IgD antibodies are found in small amounts primarily in the tissues that line the belly or chest. How they work is not clear. Compose 0.2%
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IgE Binds to Mast Cells and Basophiles Found in the Lungs, Skin, Mucus Membranes / 0.002% Protects the host against invading parasites causing the body to react against foreign substances such as pollen, fungus spores, and animal dander. They may occur in allergic reactions to milk, some medicines, and some poisons.
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IgE antibody levels are often high in people with allergies resulting in release of histomine (redness or hives)
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Antibody Titer The antibody level in the blood is a reflection of the body's past experience or exposure to an antigen, or something that the body does not recognize as self.
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Immunological Memory Titers for IgM usually rise abruptly at the time of infection–acute phase and fall slowly; during the 'convalescent' phase, IgG then increases and stays elevated for life.
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Apoptosis Programmed Cell Death that Unneeded Lymphocytes Undergo 100 Million Daily Produced and Destroyed Shrink / Ingested Violent Death (Bursting) Triggers Inflammation
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