MOUSE EAR SPLEEN GRAFTS - A MODEL FOR INTRASPLENIC IMMUNIZATION WITH MINUTE AMOUNTS OF ANTIGEN

The production of monoclonal antibodies to protein antigens which can only be obtained in tiny amounts has been a major task, since classica l in vivo immunization procedures are not always efficient. In order t o circumvent this problem, two methods have been developed: (1) in vit ro immunization, in which the immunogen is presented directly to splee n cell cultures; (2) intrasplenic immunization, a technique in which t he immunogen is deposited in the spleen tissue. The latter approach re quires less laboratory work and the risk of contamination, often a pro blem with in vitro cultures (Nilsson and Larsson, Immunol. Today (1990 ) 11, 10), is greatly reduced. Here, we describe a novel method of gra fting neonatal spleens in the pinna of the mouse ear. Histological and functional studies show that these spleen grafts have white and red p ulp and contain normal percentages of functional T and B cells. The re sults indicate that this procedure is extremely efficient in priming m ice for a secondary humoral immune response, since very small amounts of soluble antigen (ovalbumin) were required. The data are discussed i n terms of the advantages of this new technique over current procedure s for intrasplenic immunization.