Immunological detection of proteins after isoelectric focusing in thin layer agarose gel: a specific application for the characterization of immunoglobulin diversity.

A simple and relatively rapid method was developed for the characterization of immunoglobulins from serum samples. After isoelectric focusing in a thin layer agarose gel proteins were transferred on to a nitrocellulose sheet by pressuring the focused gel against the sheet. A certain immunoglobulin class was stained on the sheet using alkaline phosphatase conjugated anti-immunoglobulins and the specific colour staining of the enzyme. The method allows the use of serum dilutions up to one thousand and conjugate dilutions up to two thousands. It was possible to strengthen the weak staining of antigens using a longer staining period and changing the substrate-dye solution without any background colorizing of the sheet. A specific application for the characterization of serum immunoglobulins of IgG class of a myeloma patient is presented.