Research seminars Adjustable locks and flexible keys: New paradigms in antibody specificity

Among the fundamental issues critical for body's defense is the maintenance of self-nonself discrimination. Considering that the non-self antigenic space is indeed limitless, how does the immune system efficiently handle this discrimination within a biological energy 'budget'? Can the immune system afford a unique antibody for every new antigen that is encountered? Are there strategies built into the immune system to cope with the pathogenic intelligence? Crystallographic studies have provided interesting insights concerning these issues. Structural data pertaining to the interactions between germline antibodies and their corresponding antigens redefine antigen recognition within the established norms of structural chemistry bringing out intriguingly new aspects of antigen recognition in humoral antibody response. It was discovered that while conservation of conformational repertoire is a key characteristic of mature antibodies achieved through affinity maturation, the germline antibodies maintain substantial plasticity at the initial stages of antigen encounter accommodating a broad specificity repertoire. Indeed, the versatility of antigen-antibody interaction is a physiological requirement.