Medical Interventions 1.4

What is a vaccine / vaccination?

A preparation that contains weakened, killed, or parts of pathogens that trains the immune system to recognize and fight that pathogen in the future.

How does a vaccine cause immunity?

It exposes the immune system to antigens, causing B-cells to make antibodies and memory cells that protect against future infections.

How has vaccination impacted disease trends in our country?

It has greatly reduced or eliminated many serious diseases and lowered infection, disability, and death rates.

What methods are used to produce vaccines in the laboratory?

Using weakened pathogens, killed pathogens, toxoids, pathogen parts (subunits), or genetically engineered DNA/viral vectors.

What is recombinant DNA technology?

A genetic method where DNA from different sources is cut and combined to create new DNA used to produce proteins, medicines, and vaccines.

What molecular tools are used to assemble recombinant DNA?

Restriction enzymes cut DNA at specific spots, and ligase glues DNA fragments together.

How can engineered plasmids be inserted into bacterial cells?

By heat shock or electric shock, which temporarily opens the bacterial membrane so plasmids can enter.

How can recombinant DNA and bacterial cells be used to produce vaccines?

Bacteria with engineered DNA produce antigen proteins, which are purified and used as vaccines.

What is epidemiology?

The study of how diseases spread, who they affect, and how to control or prevent them.

How can epidemiologists assist with disease detection, prevention, and treatment?

They track outbreaks, find causes, test prevention strategies, and recommend effective treatments.

Describe how vaccines cause immunity.

Vaccines create immune memory by stimulating antibody and memory B-cell production without causing the disease.

Compare first vs. second exposure to the same pathogen.

First: slow response, few antibodies. Second: faster, stronger response due to memory cells.

Compare active and passive immunizations.

Active: body makes its own antibodies, long-lasting. Passive: receive antibodies from another source, short-lasting.

Explain herd immunity.

When most people are immune, spread of disease is blocked, protecting individuals who are not vaccinated.

Explain why some vaccines require boosters or multiple doses.

Immunity can weaken over time or needs multiple exposures to form strong memory cells.

Identify and compare vaccine manufacturing methods.

Live-attenuated: weakened pathogen; Inactivated: killed pathogen; Toxoid: inactivated toxins; Subunit: pathogen pieces; DNA/Vector: genes that produce antigens.

Explain creating recombinant DNA.

Select a restriction enzyme

Explain how restriction enzymes and ligase work.

Restriction enzymes cut DNA at specific sequences; ligase connects DNA fragments by sealing sugar-phosphate bonds.

Describe how plasmids are used in genetic engineering.

Plasmids carry new genes into bacteria so they produce proteins or antigens for vaccines.

Describe how recombinant DNA technology can produce vaccines.

Inserts antigen genes into a plasmid

Steps in an outbreak investigation.

Confirm outbreak

Analyze disease data and evaluate prevention/treatment.

Look for patterns, test hypotheses, and determine which actions or treatments reduce disease most effectively.

Vaccination

The process of giving a vaccine to produce immunity.

Pathogen

A microorganism (virus, bacteria, etc.) that causes disease.

Antigen

A molecule on a pathogen that triggers an immune response.

B-cells

White blood cells that make antibodies against antigens.

Antibodies

Proteins that bind to and neutralize specific pathogens.

Memory cells

Long-living cells that remember pathogens for faster future protection.

Active immunization

Immunity created by the body after infection or vaccination.

Passive immunization

Immunity received from another source (ex: antibodies from mother or injections).

Booster

An additional vaccine dose that strengthens or refreshes immunity.

Herd immunity

Community protection that occurs when enough people are immune to stop disease spread.

Similar pathogen vaccine

Uses a harmless but closely related pathogen to create immunity.

Killed / inactivated vaccine

Uses pathogens that are dead so they cannot cause disease.

Live, attenuated vaccine

Uses weakened pathogens that can still trigger an immune response but not illness.

Toxoid vaccine

Uses inactivated toxins made by bacteria to train immunity against toxin-caused disease.

Subunit vaccine

Uses only specific pieces of a pathogen (like surface proteins) to stimulate immunity.

Naked-DNA vaccine

Uses DNA that instructs cells to make antigen proteins which trigger immune responses.

Recombinant vector vaccine

Uses a harmless virus or bacterium to deliver antigen genes into the body.

Recombinant DNA

DNA formed by combining genetic material from different organisms.

Restriction enzyme

A protein that cuts DNA at a specific sequence.

Restriction sequence

The exact DNA pattern that a restriction enzyme recognizes and cuts.

Sticky ends

Overhanging DNA ends after being cut that can easily join with matching DNA.

Ligase

Enzyme that links DNA fragments together to form a continuous strand.

Plasmid

Small circular DNA in bacteria used to carry and express inserted genes.

Epidemiology / Epidemiologist

The field/scientist that studies disease patterns and how to control them.

Epidemic curve

A graph showing the number of disease cases over time during an outbreak.

Cohort (prospective) study

Follows a group of people over time to see who develops a disease.

Case-control (retrospective) study

Compares people with a disease to those without to find risk factors.