The lymphocytes all look quite similar but functions can be very different!

The lymphocytes all look quite similar but functions can be very different! For example, B and T cells are two kinds of lymphocytes that are practically indistinguishable under the light microscope, but have completely different functions, as you will learn later this semester. What might be some ways that lab scientists could distinguish these two cell types (tell them apart)?

Being able to distinguish the different cell types of the immune system by morphology or other means is one thing; but figuring out what the different cell types actually do is another challenge entirely

a) What are some ways that you can imagine to figure out what the different cell types do? b) What organism would you use? Are there any caveats?