The use of monoclonal antibodies in the characterization and purification of cell surface antigens of Listeria monocytogenes serogroup 4.

Soluble antigen was prepared from Listeria monocytogenes serovar 4b using a formamide extraction method. Antigenic material was detected in this extract by gel diffusion and ELISA using anti-Listeria monoclonal antibodies. Using this ELISA, antigen was detected in cerebrospinal fluid (CSF) during infection due to L. monocytogenes serovar 4b with wells coated with three of the monoclonal antibodies (CL1, CL2 and CL3). The antigen binding of CL3 was found to be greatly influenced by changes in ionic strength, and these properties were utilized in an affinity purification method. An analysis of the antigens was carried out using crossed immunoelectrophoresis and this indicated that the crude formamide extract contains a number of distinct antigens. A group of three antigens of differing electrophoretic mobilities were demonstrated in the affinity purified material.