Unbroken skin, mucus, and tears stop pathogens before they enter the body. What line of defense do these provide?

Stomach acid and lysozyme in saliva can destroy microbes. How are these defenses classified?

A pathogen gets through a cut, and the area becomes warm, swollen, and red. This response is part of which line of defense?

A phagocyte surrounds and digests a microbe that has entered the body. What line of defense is this?

B cells and T cells respond to a particular antigen. What line of defense are they using?

Which cells produce antibodies that identify and neutralize foreign substances?

Which immune cells attack body cells that are already infected?

A white blood cell detects a bacterium, engulfs it, and clears it from the body. What type of cell is it?

A B cell develops into a plasma cell and releases proteins that bind a specific antigen. What type of protein is it releasing?

Cell-mediated immunity relies mainly on which type of immune cell?

Besides engulfing pathogens, a macrophage also displays fragments of the pathogen on its surface to activate other immune cells. What is this second function called?

After an infection clears, some immune cells persist for years and let the body respond faster if the same antigen returns. What are these long-lived cells called?

After recovering from an infection, Omar's own immune system has antibodies against that pathogen. How was this immunity acquired?

Rina receives a vaccine, and weeks later her body has made antibodies against the disease. What kind of immunity is this?

A newborn receives antibodies from the mother through the placenta before birth. What kind of immunity does the newborn receive?

After a high-risk exposure, a patient receives immune globulin containing donated antibodies for immediate protection. What kind of immunity is this?

Kai was infected with a pathogen but had no symptoms. Later, tests show that Kai's immune system made antibodies to it. What kind of immunity developed?

A student needs immediate protection, but the protection may fade within months because the student receives ready-made antibodies. What kind of immunity is this?

What does an antigen in a vaccine do?

Devon is vaccinated on Monday and exposed to the disease on Tuesday. Why might the vaccine not protect Devon immediately?

Why can a vaccine help build protection without causing the full disease?

A friend says, “A vaccine gives you antibodies made by another person.” What is the best correction?

What is the purpose of a booster dose when vaccine protection has faded?

After vaccination, Talia has mild tiredness for a day. Which explanation best fits this effect?

A newborn is too young for a certain vaccine, but nearly everyone in the household and neighborhood is immune. What protects the newborn by reducing disease spread?

A school has high vaccination coverage, so a contagious disease has difficulty moving from student to student. What is this called?

Mara cannot receive a vaccine because of a medical condition. Her community's high immunity lowers her chance of exposure. What is this protection called?

A virus enters a town where few people are immune, and it spreads quickly through many households. What kind of protection is weak in this town?

Measles is very contagious. Why does it need a higher share of people to be immune than a less contagious disease before herd immunity works?

How does herd immunity protect a person who is not immune?