Slide 1Why is this important?ImmunizationA Brief History of ImmunizationA Brief History of ImmunizationA Brief History of ImmunizationActive ImmunizationAttenuated (Live) VaccinesInactivated (Killed) VaccinesToxoid VaccinesCombination VaccinesVaccines Using Recombinant Gene TechnologyRecommended ImmunizationsRecommended ImmunizationsVaccine SafetyPassive ImmunotherapyPassive ImmunotherapyM I C R O B I O L O G YWITH DISEASES BY BODY SYSTEM SECOND EDITIONChapter 17Immunization and Immune TestingTHIRDWhy is this important?•Vaccination is the most efficient and cost-effective method of controlling infectious diseases•Many infectious diseases are now controlled or even eliminated due to vaccination•The administration of antibodies can further reduce incidence of disease and prevent deathImmunization•Active immunization – administration of a vaccine so that the patient actively mounts a protective immune response•Passive immunotherapy – a patient acquires temporary immunity through the transfer of antibodies formed by other individuals or animalsA Brief History of Immunization•The Chinese noticed that children who recovered from smallpox did not contract the disease again (12th century)–They infected young children with ground smallpox scabs to induce immunity in these children, a process known as variolation–The use of variolation spread to England and America but was stopped due to risk of death •Edward Jenner discovered process of vaccination by inoculating crusts from a person infected with cowpox (related but very mild disease)–Vaccination, vaccine–No one understood how this worked or whether similar techniques could protect against other diseases•Practice of transferring antibodies was developed when it was discovered vaccines protected through the action of antibodiesA Brief History of Immunization•By the late 1900s, there were vaccines that significantly reduced the number of cases of many infectious diseases•Have successful vaccines against some types of cancer•Eradication of smallpox•Hoping for worldwide eradication of polio, measles, mumps, and rubellaA Brief History of Immunization•A variety of political, social, economic, and scientific problems prevent vaccines from reaching all those who need them–In developing nations worldwide, over 3 million children still die each year from vaccine-preventable infectious diseases•Effective vaccines have yet to be developed for some pathogens•Vaccine-associated risks (medical and financial) discourage investment in developing new vaccinesActive Immunization•In all active immunizations, the pathogen is altered or inactivated; less likely to cause illness–Not all types of vaccines are equally safe or effective–Effectiveness is determined by checking the antibody titer (concentration of IgG and IgM) in the bloodAttenuated (Live) Vaccines•Use pathogens that have reduced virulence so they do not cause disease–Attenuation•Cause very mild infections but no serious disease under normal conditions•Contain active microbes that stimulate a strong immune response due to the large number of antigen molecules that are available–Humoral and cell-mediated immunity•Vaccinated individuals can infect those around them, providing contact immunity•Usually very effective•Can be hazardous because modified microbes may retain enough residual virulence to cause disease in immunosuppressed people•Pregnant women should not receive•Organisms may revert to wild type or mutate to a form that causes diseaseInactivated (Killed) Vaccines•Two types – whole agent vaccines and subunit 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 because the microbes don’t replicate and don’t provide many antigenic molecules to stimulate the immune response–Booster doses often required for full immunity –Often contain adjuvants, chemicals added to increase the effective antigenicity•No contact immunity stimulated•Nonantigenic portions occasionally stimulate painful inflammatory response in some•Stimulate humoral immune responseToxoid Vaccines•Sometimes more efficacious to induce immune response against bacterial toxins than against cellular antigens •Toxoid vaccines are chemically or thermally modified toxins used to stimulate active immunity•Stimulate humoral immunity•Require multiple childhood doses and reinoculations every 10 years because they possess few epitopesCombination Vaccines•Combine antigens from several toxoids and inactivated pathogens that are administered simultaneously–MMR–PentacelVaccines Using Recombinant Gene Technology•Researchers are always seeking to make vaccines that are more effective, cheaper, and safer and to make new vaccines against pathogens that have been difficult to protect against•A variety of recombinant DNA techniques can be used to make improved vaccines–Selectively delete virulence genes–Produce large quantities of very pure antigens for use in vaccines–Live recombinant vaccines–DNA vaccinesRecommended Immunizations•Important that patients follow the recommended immunization schedule not only to protect themselves but also to provide herd immunity–The protection provided all individuals in a population due to the inability of a pathogen to effectively spread when a large proportion of people (>75%) are immuneRecommended ImmunizationsVaccine Safety•Mild toxicity most common –Pain at injection site or, in rare cases, general malaise or fever high enough to induce seizures–More common with whole agent vaccines that contain adjuvant–In rare cases, toxicity may result in general malaise and a high fever–This may be sufficient to discourage people from being immunized of having their children immunized•Risk of anaphylactic shock (allergic reaction)•Residual virulence from attenuated viruses•Allegations that certain vaccines against childhood diseases cause or trigger autism, diabetes, and asthma–Research has not substantiated these allegations–Modern vaccines are much safer than those in use even 10 years agoPassive Immunotherapy•Administration of preformed antibodies to a patient•Used to provide immediate protection against a recent infection or a ongoing disease –Does not require the body to mount a response;