Abstract: This invention provides a method of identifying or characterising an immune response in a subject comprising: (a) contacting a sample containing immunoglobulins from the subject with at least one antigen immobilised on a support; (b) washing unbound, non-antigen specific immunoglobulins from the support to leave antigen-specific immunoglobulins bound to the antigen on the support; (c) optionally eluting the antigen-specific immunoglobulins from the antigen on the support; and (d) subjecting the antigen-specific immunoglobulins to mass spectrometry to identify two or more different antigen specific immunoglobulin classes, subclasses and/or light chain types.

Abstract: This document relates to materials and methods for identifying and/or quantifying immunoglobulins from a biological sample without pre-purification of the immunoglobulins prior to ionization and detection using mass spectrometry. For example, a monoclonal light chain from a monoclonal immunoglobulin may be observed using matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry after diluting a sample containing the monoclonal immunoglobulin with an aqueous buffer containing acid and a reducing agent then mixing the sample with alpha-cyano-4-hydroxycinnamic acid matrix (CHCA). In another example, an intact monoclonal immunoglobulin may be observed in a sample using MALDI-TOF mass spectrometry after diluting the sample containing the monoclonal immunoglobulin with water then mixing the sample with CHCA matrix.

Abstract: The invention relates to methods and materials useful for determining the actual amount of a selected polypeptide in a sample, by measuring the amount of a cleavage product released from the selected polypeptide and using an exogenous polypeptide corresponding to the cleavage product as a standard. These methods and materials can be used, for example, to quantify the actual amount of one or more selected polypeptides in complex samples.