Infectious Diseases: Unit 5

How do we get better?

In earlier units we discussed how the immune system provides different ‘layers’ of protection focusing mainly on immune barriers. Now we will turn our attention to how innate and adaptive immunity function. We will simplify the processes of innate and adaptive immunity into two stages, recognition and response. So far we have described the immune system as a series of barriers that protect the host from microbes. In this unit, the students will explore the immune response that takes place when a microbe penetrates the sterile environment of the host.

Lesson 1

Our body’s barriers — the innate immune system

After reviewing the immune structures we saw in Unit 1, we focus on how cells of the innate immune system recognize and respond to pathogens. The immune system is able to ‘see’ the world as ‘self’ and ‘non-self’ via receptors that have evolved to recognize relatively conserved structures in microbes that do not exist in humans. Once they recognize a non-self entity, innate immune cells respond by phagocytosing the threat and sounding the alarm (by releasing cytokines and triggering chemotaxis). Most infections are stopped by innate immune responses!

Objectives – Describe innate immune structures and functions.
– Explain how innate immune cells recognize a pathogen.
– Explain innate cell response.
Activities – Review immune structures and functions.
– Videos
Materials Printed Materials:
– Lesson worksheet
– Card deck (to be used in Lesson 5.4)

– Videos (see PPT)
Homework Begin using card deck to prepare for Lesson 5.4

Lesson 2

Evolving pathogens — the adaptive immune system

This lesson transitions from innate immune responses to adaptive responses. It deals with the three complex principles of adaptive immunity: a) Each B and T cell can recognize only one ligand; b) each B and T cell recognizes this ligand with a unique receptor that is produced randomly; and c) these receptors are on a single B or T cell, so they need to clonally expand before responding to a threat. To understand the concept that B and T development is molecular evolution, students cut and paste antibodies randomly, then a pathogen is revealed to see if someone created an antibody specific for that pathogen (antigen).

Objectives – Explain difference between B and T cell receptor-antigen binding.
– Describe how randomly generated receptors allow immune system to ‘see’ pathogens.
– Explain the need for clonal expansion.
Activities Design an antibody.
Materials Printed Materials:
– Instructions
– Antibody printouts
– Lesson worksheet
Homework Use card deck to review major points of today’s lesson.

Lesson 3

Evolving pathogens—our body’s responses—B and T cells

The last lesson explored the idea that each B and T cell randomly makes a single receptor that is specific to a unique ligand. This cell then divides (clonal expansion), making exact copies of itself to respond to the threat. This lesson describes how B and T cells respond to disarm and kill pathogens after they have expanded. This includes antibodies production by B cells, killer T cell function, and processes T helper cells use to orchestrate the immune response.

Objectives – Explain clonal expansion
– Draw a flow chart to describe B cell-antigen recognition.
– Describe the three ways antibodies inactivate pathogens.
– Explain T killer cell responses.
– Explain T helper cell responses.
Activities – Discuss clonal expansion, B and T cell response
– Complete worksheet diagrams.
Materials Printed Materials:
– Lesson worksheet
Homework Review card deck in preparation for Lesson 5.4. Remind students to bring the cards they got during Lesson 5.1.

Lesson 4

Putting it all together — a card game

A major challenge of learning about the immune system is seeing how all the pieces work together. In this lesson students will draw connections between innate and adaptive recognition and responses, as they create cartoons of for an immune response to select pathogens. The students will have their notes, a dichotomous key, and immune cards for help.

Objectives – Illustrate sequence of body response to pathogens.
– Summarize the big picture view of body’s innate and adaptive immune responses.
Activities Use the cards to put together the steps of an immune response in two different situations.
Materials Printed Materials:
– Lesson worksheet
Homework Write paragraph on how to boost immune system.

Lesson 5

What makes a good vaccine?

This lesson is intended to offer the students an opportunity to apply their knowledge of immunology and infectious disease to learn about vaccination. We begin by asking students to discuss the qualities of a ‘good and bad’ vaccine, then, we review the processes needed to make immune memories as we look at common methods for vaccination.

Objectives – Describe pros and cons of the main types of vaccines.
– Explain how vaccines work.
– Describe the good qualities of a vaccine.
Activities – Video clip.
– Pros and Cons of Vaccines.
Materials Printed Materials:
– Lesson worksheet
– Unit quizzes
Homework – Prepare for Great Vaccine Debate.
– Study for Unit 5 quiz

Lesson 6

The Great Debate – Are vaccines worth the risk?

This lesson is the final activity of the module. In this lesson the students will prepare for and execute a debate about the pros and cons of vaccination.

Objectives – Evaluate formal sources of information
– Argue the Pros and Cons of vaccines
Activities – Socratic Debate: Pros and Cons of Vaccines
Materials Printed Materials:
– Sources of evidence for debate
– Vaccine debate instructions and rubric