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surface molecules of sufficient size, structural complexity. epitopes. membrane protein (antigen). Antigens, Epitopes. capsule proteins (“K antigen”). cell wall components. cytoplasmic proteins. exotoxin. flagellar proteins (“H antigen”). pili proteins. viral surface proteins.
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surface molecules of sufficient size, structural complexity epitopes membrane protein (antigen) Antigens, Epitopes
capsule proteins (“K antigen”) cell wall components cytoplasmic proteins exotoxin flagellar proteins (“H antigen”) pili proteins viral surface proteins Microbial Antigens
epitope Response to Antigens antigen antibody
Opsonization Neutralization toxicity site antitoxin toxin Agglutination phagocyte Viral inhibition* Precipitation Alcamo Fig. 18.18 antigen *a.k.a. viral neutralization
Terminology • Immunoassay • Serology
increasing amount of antigen Same amount of antibody in each tube precipitate No precipitate No precipitate Amount of precipitation Amount of antigen optimal proportions antigen excess antibody excess Precipitation Reactions
Alcamo, I.E. (2000) Fundamentals of Microbiology 6th Ed. Fig. 19.4 Antibody Titer
Black, J.G. (2002) Microbiology: Principles & Explorations 5th Ed. Fig.18.32 Hemagglutination http://www.tdh.state.tx.us/lab/serology_agg.htm
antigen attached to slide & flooded with patient’s serum 1 antibody (IgG) from patient’s serum antigen bound to slide fluorescent labeled anti-IgG anti-globulin added 2 anti-IgG (antiglobulin) fluorescent label Principal of Fluorescent Antibody Assays
Antigen attached to well of polystyrene plate 1 Protein such as gelatin is added to block the uncoated surface 2 Enzyme-Linked ImmunoSorbent Assay (ELISA) Alcamo Figure 19.12
3 Patient serum is added; complementary antibody binds to antigen 4 Enzyme-linked anti-antibody is added and binds to patient antibody Enzyme’s substrate is added & reaction produces a visible color change 5 ELISA
http://virology-online.com/presentations/Tests.htm ELISA Microtiter Plate