Some serological characteristics of normal incomplete cold antibody.

The finding that the presence of normal incomplete cold antibody in cord serum is independent of its presence in the corresponding maternal sample suggests that the antibody is produced by the newborn infant. The observation that the antibody has a constant titre in newborn infants aged between a few weeks and 6 months points to the same conclusion. The normal incomplete cold antibody differs from other blood group antibodies in its thermolability, in being present in the serum of patients with severe hypogammaglobulinaemia and in its interaction with some polysaccharides and bacteria. In many respects the antibody resembles properdin, but markedly differs from properdin in its specificity and other serological characteristics.