While you read up on vdj, know that the heavy chain has the vdj and there is dna rearrangement. know the l and h chains are made separately in the cytoplasm by means of disulfide ! the last step is the addition of the carbohydrate moiety. (look and remember my capital
second, at first, all b lymphocytes carry igm specific then after undergo class switching to the others (if you were lost here, you really need to know immuno and review)