*Vaccines

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What is natural immunity?

Acquired through the normal life experiences, not induced through medical means.

What is natural-passive immunity?

Babies are born with functional innate but immature adaptive response.

Placenta tranfers lare amounts of maternal antibodies (IgG)

Breast milk contains protective antibodies (IgA)

No memory lymphocytes = no long-term immunity.

Describe natural-active immunity

Results when a person develops their own immune response to a microbe through infection.

The body will make antibodies against the pathogen to overcome that specific infection. Memory lymphocytes will be made and will provide better future response.

Describe artificial immunity

Provided purposefully through medical procedures (immunization)

Describe artificial-active immunity

Results when a person develops their own immune response to a prepared microbial antigen (vaccines)

Describe artificial-passive immunity

Results when a person is given selected immune substances made by another individual. Snake venom, cancer, pathogens can all be specifically targeted using antibodies.

• IVIG = intravenous immunoglobulin

• Immunotherapy

Define immunoprophylaxis

Prophylaxis is a preventative measure to protect against disease.

Immunoprophylaxis = offers protection if obtained before infection.

What are the characteristics of an effective vaccine?

• low adverse effects/toxicity

• protects against natural, wild forms of pathogen

• stimulates both antibody (B-cell) and cell-mediated response (T-cell)

• Long term, lasting effects

• Doesn’t need numerous doses

• Inexpensive, long shelf life, be easy to administer

Describe live attenuated vaccine antigens

Pathogen is grown in lab conditions until they lose virulence (characteristics that cause disease).

Ex.

• OPV

• Influenza — nasal mist

• BCG (tuberculosis)

Describe toxin vaccine antigens

Exotoxins are proteins that have multiple domains with different functions.

Toxoid vaccines are modified chemically to remove the toxin’s toxigenicity (active domain) but retains its immunogenicity.

Ex.

• diptheria and tetanus toxoid vaccine

Describe killed/inactivated pathogen vaccine antigens

Pathogen is killed by heat, radiation, or chemical treatment; antigenicity is retained.

Ex.

• influenza injections

• salk polio

Describe purified pathogen subunit vaccine antigens

Fragments or purified components of pathogen are used, rather than living organism.

Antigens stimulate immunity, but no pathogen is present.

Ex.

• anthrax

• pneumococcal vaccine

Describe recombinant (single pathogen protein) vaccine antigens

DNA encoding the protein of a pathogen is expressed on a yeast cell.

Hepatitis B-virus vaccine = surface antigen on the envelope of HBV is the protective antigen.

What are the limitations of recombinant and subunit vaccines?

Antigenic variation. When you use only single antigen, pathogens can evolve to evade antibodies generated against this antigen.

Solution = produce single antigens then mix.

What are examples of vaccines that combat antigenic variation?

Pertussis (aP) — vaccine contains two or more protective antigens or Bodetella pertussis

Pneumococcal vaccine — composed of capsular polyssacharides of 23 serotypes of Strep. peneumoniae. Annual vaccination not required.

Describe a DNA/RNA vaccine antigen

A plasmid containing DNA/RNA for a specific antigen of a pathogen is introduced to a body’s cells.

What is herd immunity?

Immunizing the vast majority of the population protects the few individuals who cannot be immunized.

Which type of vaccine should not be given to a pregnant or immunocomprimised person?

Live (attenuated) vaccines should not be given to a pregnant person becuase the weakened form the vaccine could possibly cross the placental blood barrier and be transferred to the fetus.