Module 3 Flashcards
What is immunity?
Resistance to a specific disease.
What is an antigen?
A substance that produces an immune response.
AKA immunogen
Most commonly proteins
What is an antibody?
Product of immune response.
What happens when the immune response is activated?
Either the cellular immune system (T cells) or humoral system (B cells) will be activated by the antigens.
What do T cells produce and what do they destroy?
Lymphokines and memory cells.
Destroy: cancer cells, foreign cells, protozoa, fungi, Tb (smooth lipid wall) and virus infected cells
What do B cells produce and what do they destroy?
Specific antibodies (IgM then IgG) and memory cells.
Destroy: bacteria and viruses
What are antibodies?
Gamma globulin proteins that provide immune response.
What are the two types of antibodies and their functions?
IgM- first produced, remain in blood stream, large structure, indicate current/recent infection or exposure
IgG- second produced, can go into tissues/cross placenta, indicates past exposure/infection
How are antibodies produced?
B cell receptors contact antigens
B cell proliferates into a group of cells (clone) which divides into:
Plasma cells- produce antibodies
Memory cells- can be activated in the future to produce antibodies
How long after first exposure are detectable levels of antibodies produced?
Up to a week or longer
Once memory cells are established contact will give a faster response
Why are immunizations normally given in a series of three?
After primary immunization there is only a small burst of IgM and IgG after a week.
Booster shots result in an almost immediate response and a large burst of IgG.
What is a titer?
The expression of the amount of antibody present in blood.
What factors effect response to immunization?
Individual differences
Site of injection
Immunization product
Product failure
What types of products are used for immunization? Describe them.
Vaccine- suspension of altered bacteria or virus, causes antibody production
Toxoid- bacterial exotoxin treated so no longer toxigenic, causes antibody production
What are the different types of immunity and their characteristics?
Inate- associated with our species
Acquired- developed after birth
Naturally acquired- an act of nature
Artificially acquired- product given to induce immunity
Passive- host is given preformed antibodies, short term
Active- host makes own antibodies after exposure, long term
What are some examples of passive immunization?
Gamma globulin (pooled)
Hep A immune globulin
Tetanus antitoxin
Rabies immune globulin
Anti snake venom
What are standard immunization practices?
Routine schedule- mom’s antibodies provide for the first 2-3 months, then given immunizations
Booster shots
Yearly flu vaccine (different strains)
What diseases are immunized against routinely?
Diphtheria Pertussis Tetanus Measles Mumps Rubella Polio Hib Chicken pox Meningococcal conjugate Pneumococcal conjugate Hep B
When is the BCG vaccine for Tb given?
In provinces/territories where Tb is endemic.
Why are booster shots given?
To maintain memory cell numbers at a protective level.
What are the symptoms of rubella?
Mild rash for 2-3 days
Often subclinical
Why is rubella immunization important?
If contracted during pregnancy, the virus can cross the placenta.
Fetus may be aborted/stillborn.
Children born with several defects.
Why can’t pregnant women be immunized against rubella?
Made from the virus, can cross the placenta and affect the fetus.
What is hepatitis?
Viral liver infection spread by bodily fluids, primarily blood.
Who should be immunized against Hep B?
All healthcare workers at risk to exposure to blood or bodily fluids or sharps injuries.
What is the immunization schedule for Hep B?
First two shots one month apart, third 6 months after the first.
Protective level after third.
How is successful immunization for Hep B determined?
Blood test for anti hepatitis surface antibodies (anti HBs)
Booster- under review
What is another product available for Hep B prevention and when is it given?
Hep B immune globulin (HBIG).
Preformed antibodies (passive immunity).
Used after blood/mucous membrane exposure to Hep B virus when there’s no evidence of anti HBs immunity.
Within 48hrs.
What is the chicken pox virus and what does it cause?
Varicella-zoster, herpes group virus
Chicken pox- generalized infection
Shingles- reactivation of latent virus in older and immunocompromised patients, painful eruptions of nerve endings
How is the risk of chicken pox to immunocompromised patients reduced?
Immune statues of workers are determined
Non immune staff are immunized
Non immune workers who are exposed aren’t allowed around immunocompromised patients for 10-21 days after exposure (incubation period)
Why is Tb a serious problem?
The number of infected and diseases is increasing
Emergence of drug resistant strains
How is Tb spread?
Direct contact with respiratory secretions or droplet nuclei (greatest danger)
What happens after a tubercle bacilli is inhaled?
Bacteria multiply slowly (3-6wks)
Cellular immune system is activated
Spread is halted by granulomata
Person is infected but not diseases, isn’t contagious
How is the risk of Tb infection minimized in hospital?
Recognize high risk patients
Understand how it’s spread
Use Tb skin testing
Use anti-Tb drugs when appropriate
Wearing a special mask when a patient is known to have Tb
What happens after Tb infection?
About 5% develop Tb
About 5-10% may develop it later in life
Dormant bacteria can be reactivated if the immune system is compromised (AIDS patients)
What are the symptoms of Tb?
Initially vague- cough, fever
Later- bloody sputum, organ dysfunction
What is the Tb skin test?
AKA Mantoux test
Intradermal injection of tubercle protein
Used to identify infected individuals
What does a positive Tb test indicate?
Your body has seen the tubercular protein at some point, memory cells were activated.
Have Tb, had Tb, inhaled bacteria (infected but no disease), immunized
Further testing is done
When is Tb testing done?
At the start of employment
On a regular basis after initial testing
Following a known exposure
What is immunization?
Process by which resistance to infection is induced or augmented.
Development of immunity without having the disease.
