Age-Related Prevalence of Human Serum IgG and IgM Antibody to the Core Glycolipid of Escherichia coli strain J5, as Measured by ELISA

Administration of antibody to Escherichia coli</it> strain 15 reduces mortality in patients with gram-negative septic shock. Limited evidence suggests that this antibody is present in the serum of healthy individuals and deficient in persons with malignancy; however, the age-related prevalence of serum antibody to strain 15 in normal subjects is unknown. We developed an ELISA method to measure IgG and IgM antibody to purified 15 lipopolysaccharide (LPS) in sera from 33 maternal-newborn cord pairs, 40 neonates, and 253 individuals aged from one day to twenty years. Reciprocal geometric mean titers for serum antibody to strain 15 LPS were as follows: maternal-IgG, 12.3; IgM, 174; one month old or less-IgG, 8.3; IgM, 5.6; one to 24 months old —IgG, 10.5; IgM, 44.7; >24 months old — IgG, 16.2; IgM, 200. Weconclude that human serum antibody to 15 LPS is predominantly IgM and that it is usually present by two years of age. The ELISA method should provide a valuable tool in studying the relation of core glycolipid antibody to immunity and therapy of gram-negative bacterial infections.