Abstract: A rat myeloma cell line which does not express an immunoglobulin chain, YB2/3.0.Ag.20, is prepared from the cell line Y3-Ag 1.2.3 via a hybrid myeloma cell line. This cell line, and variants thereof prepared by passaging and/or cloning the line, may be fused with immunocyte cells from an animal sensitized to an immunogen to produce hybrid myeloma cell lines which provide a source of monoclonal antibodies to said immunogen.

Abstract: A process for producing a reactive ion-etched structure with height and width dimensions of the order of 25 microns or less on a ferrite substrate surface is disclosed. A mask of positive water saturated photoresist is formed on the substrate. A metal taken from the group consisting of nickel and a nickel-iron alloy is plated through the mask. The photoresist mask is removed to leave a pattern in the plated metal. The ferrite substrate surface that is exposed by the pattern is reactive ion etched with a power density of >1w/cm.sup.2 and a bias voltage <-100 volts.

Abstract: Hybrid cell lines for providing antibodies are produced from a rat myeloma cell line having the C.N.C.M. designation I-078. In production of the hybrid cells, the rat myeloma cell line is fused with immunocyte cells such as spleen cells from an animal such as a rat sensitized to an immunogen. Use of the rat myeloma cell line is particularly advantageous for in vivo cultivation of a hybrid cell line to produce antibodies.