Catalysis by antibodies to VIP

Antibodies are hypervariable proteins important in immunological defense and the pathogenesis of autoimmune disease. We have observed autoantibodies to VIP in healthy humans and patients with airway disease. Some of these autoantibodies catalyze sequence-specific hydrolysis of VIP. Amino acid residues located at considerable distance from the scissile bond appear to be important in determining the specificity of the antibodies. Since the light chains subunits of the autoantibodies were observed to hydrolyze VIP with greater velocity than the intact IgG fractions, the heavy chains may serve as inhibitors of catalysis