130 likes | 146 Views
Chapter 17: . Immunization and Immune Testing. Immunology. Based on adaptive (specific) immunity Humoral or antibody mediated B cells produce antibodies Cellular T cells can directly attack pathogens. Immunization. Two Artificial Methods of Immunity Active immunization
E N D
Chapter 17: Immunization and Immune Testing
Immunology • Based on adaptive (specific) immunity • Humoral or antibody mediated • B cells produce antibodies • Cellular • T cells can directly attack pathogens
Immunization • Two Artificial Methods of Immunity • Active immunization • administration of a vaccine • patient actively produces antibodies • Passive immunization • individual acquires immunity through direct transfer of antibodies
Active Immunization • Vaccine types • Attenuated (live) vaccines • Contain active pathogens with reduced virulence • stimulate a strong immune response due to the large number of antigen molecules • Can result in mild infections but no serious disease
Inactivated (killed) vaccines • Whole agent vaccines –deactivated but whole microbes • Subunit vaccines –antigenic fragments of microbes • Both types are safer than live vaccines because they cannot replicate or mutate to a virulent form • Antigenically weak so contain adjuvants
Toxoid vaccines • Modified toxins used to stimulate immunity • Stimulate antibody-mediated immunity • Require multiple doses because they possess few antigenic determinants
Passive Immunization (Immunotherapy) • Antiserum • Contains preformed antibodies • Provides immediate protection • Limitations: • Contains antibodies against many antigens • Can trigger serum sickness (allergic reaction) • May be contaminated with viral pathogens • Antibodies are degraded relatively quickly
Immune Testing • Serology • study of antigen-antibody interactions in blood serum • Diagnostic uses • Use known antibodies to detect antigens associated with an infectious agent • Use antigens to detect specific antibodies in a patient’s blood to determine exposure to a specific pathogen
Precipitation Tests • Antigens and antibodies mixed • Form large macromolecular complexes called precipitates • Correct proportions are vital to create precipitation
Agglutination Tests • Clumping due to cross-linking of antibodies with antigens • Hemagglutination used to determine blood type
Labeled Antibody Tests • Antibody molecules are linked to some molecular “label” that enables them to be easily detected • Radioactive or florescent • Used to detect either antigens or antibodies
ELISA (enzyme-linked immunosorbent assay) • Uses enzyme as label • Reaction of the enzyme with its substrate produces a colored product • Most commonly used to detect antibodies in serum