Role of immunoglobulins in protection against Shigella-induced keratoconjunctives.

Various immunoglobulin preparations were tested for their ability to protect guinea pig eyes from infection by a virulent strain of Shigella flexneri. Secretory immunoglobulin A was effective in delaying or preventing keratoconjunctivitis in eight guinea pigs when it was used to precoat the organism, and was also placed in the eye with the inoculum. Neither immunoglobulin G nor immunoglobulin M gave any protection when used in the same way. Protection by secretory immunoglobulin A appeared to be related to the antishigella antibody content of the immunoglobulin since a low-titered preparation gave less protection than a higher-titered one.