Immunoglobulins, secretory component, and transferrin in eye secretions of infants in regions with and without endemic trachoma.

Eye secretions were collected from Boston and Saudi Arab infants between 1 day and 6 months of age. These secretions were then tested with monospecific antisera in double diffusion and immunoelectrophoresis for the presence of immunoglobulin (Ig)A, IgM, IgG, secretory component, and transferrin. (The term "secretory component" has been chosen by the World Health Organization to replace the terms "secretory piece" and "transport piece.") Eye secretions of all newborns contained secretory component. IgA was found attached to the secretory component in samples from some infants as young as 8 days of age and in samples from most infants over 3 weeks of age. IgG and transferrin were found in most samples regardless of the age of the infant. The prevalence of the respective proteins in the eye secretions of Boston infants was found to be similar to their prevalence in the eye secretions of Saudi Arab infants, including four who developed trachoma during the study. Specific antibody to trachoma was demonstrated in the eye secretions of those infants with active trachoma, and the immunoglobulin class was determined.