The acquisition of narrow binding specificity by polyspecific natural IgM antibodies in a semi-physiological environment.

Natural IgM antibodies (Abs) play an important role in clearing pathogens, enhancing immune responses, and preventing autoimmunity. However, the molecular mechanisms that mediate the functions of natural IgM Abs are understood only to a limited degree. This shortcoming is largely due to the fact that isolated natural IgM Abs are commonly polyspecific and recognize a variety of antigens (Ags) with no apparent structural homology.