Abstract
CBA/N mice, which possess an X-linked immunodeficiency (xid), produce a convincing antibody response to lipopolysaccharide derived from Escherichia coli 0113 (LPS 0113), a thymus-independent antigen. The antibody response produced was shown to be specific for the O-polysaccharide moiety of LPS 0113, rather than lipid A or lipid-A-associated protein. The relevance of this finding to the nature of the genetic defect of xid-mice is discussed.