A simple method for producing a monospecific antiserum against IgM.

To avoid the chemical purification of mastomys IgM, a reliable alternative method for producing a specific anti-mastomys IgM antiserum was developed. It employs the strong cross-reactivity of antisera against mouse serum proteins with mastomys serum proteins. By the immunoelectrophoresis technique, precipitates of mastomys IgM and cross-reacting rabbit anti-mouse IgM were obtained. A rabbit was immunized with these precipitates. Activity against the light chains was removed from the antiserum by passage over an immunoadsorbent column of mastomys IgG. The adsorbed antiserum was found to be specific for determinants on mastomys IgM.