Development of Antilymphocyte Sera by Gross Immunization of Chimpanzees and Baboons 1,2

Summary

Two chimpanzees and 4 baboons were cross immunized biweekly with peripheral blood lymphocyte preparations, with and without Freund's adjuvant and their humoral immune responses followed by hemagglutination (HA), leukoagglutination (LA), and lymphocytotoxicity (LC). Chimpanzees and baboons responded poorly or not at all to immunization with lymphocytes from one another at dosages of less than about 10⁶ lymphocytes/kg when adjuvant was not admixed. When Freund's incomplete adjuvant (FIA) was added to preparations containing a similar amount of antigen, baboons developed LC titers of 4096 to 8192, and LC titers of chimpanzees (4–8), rose to 256. HA antibody levels increased similarly after the incorporation of adjuvant, while LA levels increased, but remained low.

When the antigen-FIA dose was increased from 10⁷ to 3×10⁷ cells/kg of body weight (42×10⁷ and 124×10⁷ total cells, respectively), peak titers of 512–1024 appeared in the sera of chimpanzees 2 weeks later. Administration of approximately 1.7×10⁷ cells/kg (69×10⁷ total cells) with Freund's complete adjuvant (FCA) resulted in little change in LC titer over that observed with FIA. Intraperitoneal inoculation of chimpanzees using spleen homogenate from baboon resulted in a substantial elevation of both LC and HA antibody titers.