HIGH HUMAN-IGG LEVELS IN SEVERE COMBINED IMMUNODEFICIENT MOUSE RECONSTITUTED WITH HUMAN SPLENIC TISSUES FROM PATIENTS WITH GASTRIC-CANCER

We implanted normal peripheral blood lymphocytes (PBL) from healthy do nors and splenic tissues from patients with gastric cancers into the s evere combined immunodeficient (SCID) mouse, demonstrating that SCID m ouse with splenic tissue can produce a high level of human immunoglobu lin G (IgG). The normal PBLs at 10(7) and 10(8)/mouse were implanted i ntraperitoneally, and three splenic tissues with a size of 3 x 3 x 3 m m from gastric cancer patients were inoculated subcutaneously into the bilateral backs of the mice. At 2, 4, 6 and 8 weeks after inoculation , mice were killed, and the human IgG was assessed by an ELISA method. SCID mice with splenic tissue revealed high human IgG levels from 2 w eeks after inoculation and approximately 2 mg of IgG per ml was observ ed at 8 weeks post-implantation, while the IgG levels in mice treated with PBLs were limited. Since the half life of the extrinsic human IgG was 10.2 days, the high level of human IgG in the SCID mice was suppo sed to be produced by human plasma cells in the splenic tissue from ga stric cancer patients. This model was thought to be adequate for evalu ating human immunological functions in vivo.