Preliminary characterization and distribution of vicia villosa binding cells in human tonsils.

The lectin Vicia villosa (VV) has been used for the separation of human and murine contrasuppressor T cells. These cells were characterized in cryostat sections of human palatine tonsils by double staining with VV lectin and monoclonal antibodies to macrophages, lymphocytes and their subsets using a fluorescein-rhodamine technique. VV lectin had an affinity for the CD8+ subset of lymphocytes and for a subset of macrophages within the germinal centre. The number and distribution of VV lectin binding cells was studied in paraffin sections of formalin fixed tonsils by the avidin-biotin-peroxidase technique. Positive cells in the germinal centres, mantle, interfollicular zones and fibrous connective tissue septa were quantified using an image analyser. These were found in greatest density in the interfollicular zone, correlating with the known distribution of T cells in human palatine tonsils. The binding of VV lectin to a subset of macrophages appears not to have previously been described nor have VV lectin binding CD8+ lymphocytes been demonstrated in sections of human tissues.