Preventing Infectious Disease Chapter 18 Section 3

Key Concepts  How does the body acquire active immunity  How does passive immunity occur?

Key Terms ImmunityActive immunity VaccinationVaccine AntibioticPassive immunity

Active immunity  Active immunity occurs when a persons own immune system produces antibodies in response to the presence of a pathogen – Ex. Chickenpox-the immune system responded to the virus antigens by producing antibodies. Next time a healthy immune system will produce antibodies so that the person will not become sick with chickenpox

Immune Response  After a person recovers from chickenpox some T cells and B cells keep the “memory” of the pathogens antigen.  Active immunity often lasts for life

Vaccination  The process by which harmless antigens are deliberately introduced into a person’s body produce active immunity  Vaccinations are given by injection, mouth, or through a nasal spray  A vaccine contains weakened pathogens you usually do not get sick you immune system responds by producing memory cells and active immunity to the disease

Antibiotic  Antibiotics kill diseases caused by bacteria or slows their growth without harming body cells  Viral illnesses do not respond to antibiotics such as the common cold. Medicines may help you feel more comfortable but don’t kill pathogens

Passive Immunity  Results when antibodies are given to a person-the person’s immune system does not make them  A person acquires passive immunity when the antibodies that fight the pathogen come from a source other than the person’s body  Passive immunity lasts no more than a few months – Baby acquires passive immunity to some diseases before birth from antibodies passed from the mother’s blood into the baby’s blood during pregnancy

What is similar about getting a disease such as chickenpox and getting a vaccine?  B cells are stimulated to produce antibodies

What is different?  A person who gets the disease is infected by pathogens that have not been weakened or killed. The person may become ill with the disease. A person who recieves a vaccine receives killed or weakened pathogens

How does a person acquire passive immunity naturally?  A baby recieves antibodies passed from the mtoehr to the baby during pregnancy

How does a person acquire passive immunity artificially?  The person is given antibodies from another sourc