6Immunoglobulin D (Ig D)
Ig D is the least understood of all five isotypes of antibodies. What is clear, however, is that it doesn’t move freely in blood. Rather, Ig E is more likely to be found bound to B cells. Though not much is known as regard its function, it has been described as a possible activator if the immune responses, and is thus helpful in the early stages of infection. It probably triggers the onslaught of Ig M antibodies during immune responses.[5]
