Terry M. Bella
In my classes I often employ activities involving models. This provides the students the opportunity to have discussions and engage in a creative process. This also allows me to circulate the room and have discussions with the students. Modeling also requires that students justify their work. This is vital to assessing their understanding of a concept. As you move about the room you can ask students to defend the nuances of their models, thus forcing them to justify their creation and be reflective about their understanding.
Comparing the Immune System to the Defense Strategy of a Nation
An easy to do activity is have students compare the components of the innate and acquired immune system to that of the defense strategy of a nation. That being said you can apply this to a state, city, or even just a building and are not bound to using a nation as the model. The importance is that students make connections between the logic of defense that humans use to that of the logic of the immune system. For example, castles have walls which can be equated to skin. This barrier, though hard to penetrate, must have some compromises. This is a modeling activity wherein students create drawings or three dimensional models and justify them. This helps to reinforce the intricacies of the immune system and the specificity of cellular roles and actions. By requiring the students to incorporate different components, as listed below in bullets, the complexity of the activity can be modulated.
Components of an effective defense:
Modeling Lymphocyte Activity
I have black lab tables in my room. These are perfect for drawing on with chalk, particularly regular, cheap, dusty chalk. Students really enjoy being encouraged to draw on the desk for a change and I use this method throughout the year to model a number of different complex concepts that involve pathways and relationships among many components.
Provide students with the article "Life, Death and the Immune System" and encourage them to use their notes and text book. Group them in threes and instruct them draw the process that occurs within the body when a new antigen has been presented by a macrophage. This is another modeling activity and you can assess them on the level of detail that they incorporate. I use a baseline requirement of including a macrophage, MHC protein, helper T-cell, killer T-cell, B-cell, memory B-cell, antigen, and antibody.
This activity is designed to take one class period with time to clean the desks after the model has been justified. In the case of a large class I have students defend their models to other students rather than to me. I circulate and grade them on this process to instill some accountability. I must note thought that I do not do peer to peer model justification until the class has had sufficient practice with the process. Sufficient practice is typically four to five times prior wherein they defend the model to me individually or to the class as a whole in presentation format.
Adaptive Immunity Activity
This activity takes one class period, the learning outcome is an understanding of the limits and functionality of adaptive immunity is. The incorporation of vaccines helps players to conceptualize how vaccines work.
The class is dividing into two teams, the "pathogens" and the "immune system". On the blank side of 50 note cards, using a marker, write two capital letters. Do not repeat any two letters. For example, you may write "TS" or "WK". The letters are arbitrary. Cut all cards in half lengthwise, leaving yourself with 50 bottoms and 50 tops. Give the tops, these are antigens, to the pathogens and the bottoms, the antigen receptors on T cells, to the immune system. Instruct the pathogens to exit the classroom. They will be entering one at a time with a randomly selected top, they are acting as antigen presenting cells. The immune system must find the complementary base for the top in their collection of cards. Once found the pathogen leaves with the top card. The bottom complement is taped to the door frame. If in subsequent pathogen entry the same top was randomly selected the pathogen is stopped at the door, modeling adaptive immunity. This may go on for several rounds, each time the pathogens are selecting random cards from the full deck. An extension is to ask the students how to model vaccinations.
This activity is simply to model how fast the adaptive immune system responds to antigens that have been encountered before. Conversely how long it takes for the immune system to deal with antigens it has not encountered.