Ferret IgG and IgM were purified from normal serum, while ferret IgA was purified from bile. The estimated molecular weights of the immunoglobulin gamma, alpha and mu heavy chains were found to be 54kDa, 69kDa and 83kDa, respectively. For immunological (ELISA) quantification of ferret immunoglobulins, we identified and characterized polyclonal antibodies towards ferret IgG, IgM and IgA. We also identified 22 monoclonal antibodies (mAbs) raised mostly against human CD markers which cross-reacted with ferret leukocytes. These antibodies were originally specific against human CD8, CD9, CD14, CD18, CD25, CD29, CD32, CD44, CD61, CD71, CD79b, CD88, CD104, CD172a and mink CD3. Finally, we identified 4 cross-reacting mAbs with specificities against ferret interferon-gamma, TNF-alpha, interleukin-4 and interleukin-8.