Douglas T. Fearon

I study the complement system, a part of innate immunity that consists of a group of serum proteins and cellular receptors that mediate anti-microbial defense before the development of an acquired immune response. I showed how six proteins of the complement system distinguished between eukaryotic and prokaryotic cell surfaces by their differing carbohydrate composition. I then demonstrated that this ancient system that evolved in invertebrates could mark an antigen so that it could be recognized 10,000-fold more effectively by the "modern" system of an acquired immunity that first appeared with vertebrates. It is hoped this complement system function can be used to develop better vaccines. Most recently, my laboratory has begun to look at immunological memory, which is the ability of the acquired immune system to respond more rapidly and effectively to antigens that it has responded to previously. We are looking at the possibility that memory lymphocytes, which mediate this phenomenon, have a stem cell-like capacity for self-renewal because they are actively suppressed from terminally differentiating to effector lymphocytes.