A demonstration of sub-population of rosetting cells in lymph nodes from sensitized guinea-pigs by zonal centrifugation.

A rate-zonal centrifugation system for the fractionation of lymphoid cell populations on light Ficoll gradients in an MSE `A' zonal rotor is described. Fractionation of sheep erythrocyte-sensitized guinea-pig lymph node cells shows a minimum of two rosette forming cell types, one of which is also plaque forming, the other not. Rebanding of selected groups of fractions on 5 ml tube gradients after rosetting can be used to achieve enrichments of four rosetting cell populations between × 110 and × 3500.