A characterization of human tonsillar lymphocytes after separation from other tonsillar cells in an isokinetic gradient of Ficoll in tissue culture medium

Purified human tonsillar lymphocytes responded less to mitogenic stimulation than did unseparated tonsillar cells. Their response to mitogens was restored when they were combined with cells from all other gradient fractions. These data are interpreted as evidence that the majority of tonsillar lymphocytes require the presence of more rapidly sedimenting cells for a maximum response to the tested mitogens. The purified tonsillar lymphocytes were 47.0% lymphocytes that have detectable surface immunoglobulin and 29.9% lymphocytes that form rosettes with sheep red blood cells. The predominant cell surface immunoglobulin was IgM. Digestion of the tonsil with trypsin yielded tenfold more plasma cells, more viable cells, and a larger proportion of blasts, histiocytes, and binucleated cells than were obtained by mechanical dissociation of the tissue.