Control of an el4 lymphoma in nude mice by passively administered antibody.

THE NUDE mouse mutant (nu/nu) is at present attracting considerable attention as an experimental model for a variety of purposes. This animal is congenitally athymic and is deficient in T cell function [1, 2]. Consequently the nude will accept allcgrafts and xenografts of both normal and ma)Lignant tissue and is being used increasingly as a carrier of human tumours [3-6]. In recent papers from our laboratories we have descrilbed the control of the EL4 lymphoma in C57BL/6 mice by the use of the globulin fraction of a rabbit anti-EL4 serum given in conjunction with or chemically linked to cytotoxic drugs [7-10]. There is an obvious attraction in using the nude mouse a a means of extending this work to human turnouts, but before doing so it would seem appropriate to explore our ability to control the development of EL4 in the nude by this approach. The paper summarizes the results of experiments in which anfi-tumour globulin was administered 24 hours after subcutaneous injection of live EL4 cells. The preparation of the antiserum has been described previously [7]. Briefly, rabbits were given three i.v. injections of live EL4 cells at 10 day intervals and were bled out 7 days after the third injection. The heat inactivated serum was absorbed with packed mouse spleen cells until it showed no reactivity in a C'-dependent lymphocytotoxic assay when tested against C57BL/6 lymphocytes. The absorbed serum was fractionated with ammonium sulphate and the total Ig fraction was used without any further purification. The nude mice were obtained from Carworth Europe (Huntingdon, England) and were fed on a conventional diet. They were kept separate from other mice and were housed irritially in normal boxes with a sealed-on filter top and subsequently in a small animal isolator with a filtered air supply (Vickers Ltd). Under these conditions we have