As you continue on in your career, you become keenly interested in the mechanisms of immune cell recruitment during the innate immune response. After years of graduate work, you discovered a new cytokine (X), which chemoattracts neutrophils. In your excitement you begin devising experiments to characterize the function and relevance of cytokine X.

1. From what you know of chemokines, predict the general structure of chemokine X and its cognate receptor.
2. Where, by what cell types, and when would you expect it to be expressed? Explain, experimentally, how you would test your hypothesis.
3. What is the effect of expression of chemokine X on the immune response. Explain, experimentally, how you would test your hypothesis.

As you are working in the lab, you obtain a major career-defining result. You have discovered a new TLR (TLR15), which recognizes either a bacterial or viral antigen. Your task to finish graduate school is to fully characterize the molecule.

1. Design an experiment to determine if your new TLR15 recognizes a bacteria or a virus. What results do you anticipate and what experimental difficulties will you potentially encounter?
2. Comment on the likely structure for the molecule and indicate a plausible signaling pathway for cellular activation.
3. Where in the cell would you expect to find this new TLR? Why? Please design and fully explain two different experiments to test your hypothesis.
4. What are the consequences of deficiency of TLR15? Please design and fully explain two different experiments to test your hypothesis.