Replica plating of cultured mammalian cells

A simple device is described which permits the replica plating of lymphocytes as well as substrate adherent fibroblasts. The replica plating device consists of an 8 × 12 array of cotton-tipped swabs (Q-tips). The principle of the replica plating system involves the use of an array of absorbent cotton-tipped swabs to transfer nonadherent lymphocytes (or conditioned medium) to corresponding wells of 96-well microtiter plates. Replica plating of substrate adherent cells requires one additional step; i.e., dislodgement of adherent cells by rotating the cotton-tipped swabs against the culture surface of each well. Once adherent cells are dislodged, replica plating of adherent cells can be carried out in an identical fashion to the replica plating of nonadherent lymphocytes. Application of the Q-tip replicator in the isolation of monoclonal antibody secreting hybridomas is also presented.