The relation between serum antibody and resistance to tumor homografts in the mouse has been investigated. Production of serum antibody in response to homografts of a transplantable sarcoma (Sarcoma 1) was demonstrated, by cytotoxic action on the cells of the tumor, and also by a hemagglutinin test. The simpler and more repeatable hemagglutinin test was further investigated.
Peak hemagglutinin titres were reached after the immunizing homografts underwent breakdown. Following transfer of lymph node cells from immunized mice into hosts of the same strain, hemagglutinin could be detected in the host serum. The course of its production showed that this secondary antibody was not elicited by transferred antigen, nor could it be due to transfer of preformed antibody. The cells developed the capacity to transfer hemagglutinin production later than the power to transfer heightened graft resistance. Spleen cells also transferred hemagglutinin production, at a later stage after immunization and to a lesser extent than cells from the regional lymph nodes.
Implantation of the sarcoma in mice pretreated with certain preparations of lyophilized or frozen tissue stimulated hemagglutinin production, although the tumor grew progressively. The regional lymph nodes participated in the response: they could transfer hemagglutinin production into secondary hosts, but not graft resistance, and indeed appeared to diminish resistance. Lymph node cells from immunized donors conferred protection against the tumor on pretreated mice. Lymph nodes from normal donors also appeared in some experiments to confer protection although the effect was obscured by the rapidity with which the growing tumor became immunologically invulnerable.
The fate of lymph node cells stained with acriflavine was followed after transfer. No effect of the staining on the power of the cells to confer immunity could be detected. Cells transferred to the peritoneal cavity passed into various host tissues, but were not found in test homografts.
The conclusion is drawn that the hemagglutinating antibody is distinct from the antibody effective in combating homografts. The similarity in this respect between the homograft reaction and sensitization is emphasized in discussion.