Immunohistochemical demonstration of B and T-lymphocyte cell surface markers: an assessment of tissue transport/storage media.

A number of solutions were tested on lymphoid tissue with a view to devising a tissue transport/long-term storage medium which would preserve the morphology and antigenicity of lymphocytes, for demonstration of B- and T-cell surface markers using monoclonal antibodies. Some of the solutions produced total loss of any recognisable tissue structure, but one newly-devised medium gave excellent preservation of morphology and nuclear detail, together with extremely good monoclonal antibody staining. This sterilised medium, Carmichael's medium*, contains a buffer and cryoprotectant: it forms a gel at 4 degrees C, but it is easily liquefied in warm water just prior to immersion of the biopsy. Sections from tissue preserved in Carmichael's Medium were found to be of equally good quality as, and in some cases better than, those which had been fresh frozen. *International patents are currently pending on the formulation of this medium, which will be available commercially through Raymond Lamb Ltd, London, England, UK.