Immunoblot analysis of antibody responses to Shigella dysenteriae type 1 infection

Immunoblot analysis was used to identify the antigenic components of the outer membrane protein (OMP) extract from Sh. dysenteriae type 1 that may be relevant in protection against infection. The OMPs were extracted by ultrasonic disruption followed by Sarkosyl extraction. The macromolecular bands were separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), electroeluted to a nitrocellulose matrix and complexed with peroxidase conjugated antibodies in human convalescent sera. IgG specific reaction was found to a major antigenic component at 57 kilodaltons. In addition, weakly reactive three antigenic determinants of greater than 57 kD and four of less than 57 kD were found. Control sera from a rabbit immunized against OMP also exhibited a similar pattern of antigenic reactivity. Some of the OMPs with high antigenicity may be important in immunoprophylaxis.