The emigration of lymphocytes from palatine tonsils after local labelling.

Lymphocytes in the palatine tonsils of normal young pigs were selectively labelled by minute multiple injections of fluorescein isothiocyanate into the tonsils. One day later the numbers of tonsil-derived lymphocytes were determined in cervical, bronchial and mesenteric lymph nodes, spleen, Peyer's patches, thymus, bone marrow and blood. Although not all tonsillar lymphocytes could be labelled by this technique, a total of approximately 0.6 X 10(9) lymphocytes emigrated from the tonsils. Relatively more lymphocytes were found in lymph nodes than in the spleen and very few in the thymus, Peyer's patches and bone marrow. This organ distribution was different from the results from selectively labelling lymphocytes in lymph nodes, spleen and bone marrow.