Chapter 25: Immunization and Vaccines Flashcards
What is immunity?
condition of being resistant to disease
What is immunization?
process by which immunity is acquired
What are the 3 types of immunity?
○ Active
○ Passive
○ Adoptive
Active Immunization
Stimulation of a person’s own immune system to mount an adaptive immune response to an antigen
Active immunization examples
○ Natural exposure to infection- production of antibodies
○ Administration of a vaccine
Passive Immunization
Transfer of antibodies from immunized hosts to a nonimmune individual
Passive Immunization examples
○ Transfer of mother’s antibodies to fetus or infant: IgG through placenta, IgA through breast milk
○ Passive immunotherapy: Commercial antibody preparations
Adoptive Immunization
Transfer of cells of the immune system (usually lymphocytes) from an immunized host to a nonimmune individual
Advantages of each immunity
○ Active immunity: Induces long-term protection
○ Passive immunity: Provides immediate protection
○ Adoptive immunity: Can transfer cell-mediated immunity
Disadvantages of each immunity
○ Active: Takes time to develop
○ Passive: Is temporary; memory not produced, Can induce hypersensitivity
○ Adoptive: Possible rejection of allogeneic cells
What is a vaccine?
○ An antigen suspension derived from a pathogen
○ Induces active immunity
Attenuation
bacteria or viruses weakened by chemical treatment, growth at different temperatures, or repeated in vitro passage in cell culture
Attenuated Vaccines
○ Use live but weakened viruses or bacteria
○ grown under abnormal culture conditions so that they are no longer pathogenic but are still capable of stimulating the immune response
Examples of attenuated vaccines: Bacteria
○ Bacillus Calmette Guerin (BCG)
Typhoid fever
Examples of attenuated vaccines: virus
○ MMR
○ Polio
○ influenza
○ Varicella
Advantages and disadvantages of attenuated vaccines
○ Stimulate both humoral and cell-mediated immunity
○ Cannot be administered to immunocompromised patients
○ On rare occasion, may revert to pathogenic form
* tend to be most immunogenic
Inactivated Vaccines
○ Intact viruses or bacteria that have been killed by treatment with chemicals or heat
○ Examples being: Influenza, Hep. A
Advantages and disadvantages of inactive vaccines
○ Can safely be given to immunocompromised individuals
○ Stimulate humoral immunity but little or no cell-mediated immunity
○ May require two or more booster doses to produce protective immunity
Subunit Vaccines
One or more purified components of a pathogen
Subunit vaccines examples
○ Toxoids
○ Polysaccharides
○ Purified proteins
○ Recombinant proteins
Toxoids
Chemically inactivated bacterial toxins that are not pathogenic
Polysaccharides
○ Biochemically purified polysaccharide from bacterial capsules
○ Requires conjugation to a carrier protein (glycoconjugates) to induce IgG production and long-term immunity
Purified Proteins
Biochemically purified components of a microorganism
Recombinant Proteins
○ Proteins produced by genetically modified nonpathogenic bacteria, yeast, or other cells
○ Examples: Hep. B, HPV
Advantages of Subunit Vaccines
○ Induce an immune response to the pathogenic component(s) of a microorganism
○ Safety; avoid administration of intact organism
Limitations of Subunit Vaccines
○ Least immunogenic vaccine
○ Require two or more booster doses to produce protective immunity
○ Must be multivalent if a broad immune response is desired
○ Require an adjuvant to increase immunogenicity
Factors Influencing Immunogenicity
○ Age
○ Immune status
○ Vaccine composition
Adjuvants
○ Substances that enhance the immune response when administered together with a vaccine antigen
○ Stimulate the innate immune system to induce release of cytokines that activate adaptive immunity
Adjuvants: examples
○ Alum
○ Oil-in-water emulsions
Adjuvants: advantages
○ Result in a faster, longer-lasting immune response
○ May increase cell-mediated immunity
Benefits of Vaccines
○ Reduction or elimination of many serious, potentially fatal diseases
○ Decreased morbidity and mortality
Adverse Effects of Some Vaccines
○ Local reactions: Swelling, tenderness at injection site
○ Generalized reactions: Low-grade fever and malaise
○ Allergic reactions: Type I or type III hypersensitivity
○ Development of disease
Standard human immune serum globulin (HISG)
○ known as gamma globulin
○ Prophylactic treatment for patients with deficiencies in antibody production
Specific human serum globulins
Used to treat unimmunized individuals who have potentially been exposed to a pathogen
Examples of Specific human serum globulins
○ Hepatitis A and hepatitis B
○ Varicella
○ Rabies
○ Tetanus
○ Respiratory syncytial virus
Animal globulins
Usually prepared from horse serum
Animal globulins: examples
○ Anti-toxins: Antibodies to bacterial toxins
○ Anti-snake venom: Neutralize toxins or venom
Monoclonal antibodies
○ Made by a single clone of B cells
○ Directed against a particular epitope of an antigen
○ Used to treat cancer, autoimmune diseases, and other disorders
