Recognition of non-self

Antigenic specificity

Memory

Figure 15.18

The body responds to antigens that enter naturally, such as during infections.

Antibodies are transferred from mother to offspring, either across the placenta (IgG) or in breast milk (IgA).

Healthcare workers introduce

antigens in vaccines; the body

responds with humoral immune responses

Healthcare workers introduce

preformed antibodies (obtained from immune individuals) as antisera and antitoxins into a patient.

• Contains immunoglobulin extracted from the pooled blood of at least 1,000 human donors

• Processing concentrates the antibodies to increase potency and eliminates potential pathogens

• Method of choice for preventing measles and hepatitis A and in replacing antibodies in immunodeficient patients

• Injected intramuscularly

• Protection lasts 2-3 months

Can be used when a human immune globulin is not available

Example: sera produced in horses for diphtheria, botulism, and spider and snake bites

Vaccination: exposing a person to material that is antigenic but not pathogenic

Stimulate a primary and secondary anamnestic response to prime the immune system for future exposure to a virulent pathogen

Two types of Vaccines Inactivated Attenuated

Figure 15.19

• Recombinant DNA technology• Trojan horse vaccine

– Genetic material from an infectious agent is inserted into a live carrier microbe that is nonpathogenic

– The recombinant microbe multiplies and expresses the foreign genes

– The vaccine recipient will be immunized against the microbial antigens

• DNA vaccines

• Most vaccines are injected by subcutaneous, intramuscular, or intradermal routes

• Only a few oral vaccines available, even though they have advantages

• Some vaccines required the addition of an adjuvant• Common side effects

– Local reactions at the injection site– Fever– Allergies

• Some patients experience reactions to the medium rather than the antigens

Not only confers protection to the individual receiving the vaccine, but it also protects public heath

Herd immunity◦ Collective immunity through mass immunization confers

indirect protection on the nonimmune members◦ Important force in preventing epidemics

Figure 15.17