The reason you can't get into the groove, is there is none. Least none that i could find, and no easy way to understand it. I've spend the better part of 2 years trying to get my head around immunology. When you get right down to it, Adaptive immunology is also innate, Pro-inflamatory cytokines are also anti, B-Cells and T-Cells seem to do very similar things, and there are what? Like 4 different types of Dendritic Cells? There is no agreed upon nomenclature for cytokines, chemokines, interleukens, interferons, ect.
Basically, it seems like the science is in need to a major overhal, like that what they did for biochem and enzymology. Nomenclature especially needs to be made more intuitive.
As a non-immunologist looking in, the field is ripe for major discoveries and advancements, but it seems like they need to get there act together though.
Advice for an undergrad? Be happy they are going into the detail they are, as nothing would make sense if they just did a cursory explanation. I found advanced immuno easier then basic for that reason.