Sandra Pepin 
University of New Hampshire
Major: Microbiology
Mentor: Frank G. Rodgers, Professor of Microbiology
Production of Monoclonal Antibodies to Components of Listeria monocytogenes Involved in Bacterial Adherence to Host Cells
This research project involved the production of monoclonal antibodies (MAbs) specific to the cell surface-associated proteins of the human pathogen Listeria monocytogenes. These MAbs will be used in competitive binding assays to define, in a blocking fashion, the process of adherence of L. monocytogenes to human host cells.
MAbs are prepared as follows: L. monocytogenes cell surface proteins were injected into mice once a week for three weeks. During this time individual B-cells of the mouse's immune system produce antibodies to each of the various components, or epitopes, of the protein. After three weeks, the B-cell enriched spleens of the mice are removed. NS-1 cells (myeloma or cancer cells) are grown at the same time and these are fused with the antibody producing B-cells. This fusion with the indefinitely reproducing cancer cells allows the hybridoma cells the ability to survive in culture. Fusion occurs by combining the collected B-cells and the cultured NS-1 cells in a 33% polyethylene glycol solution (PEG). The fused cells which result are known as hybridoma cells. After injection of individual, cloned cancerous but antibody producing hybridoma cells into mice, ascites tumors are formed in the peritoneal cavity. These tumors, derived from single cells, secrete the MAbs at very high concentrations. The MAbs will be collected from the mice for use in investigating the adherence of L. monocytogenes to host cells.
