Generation, immunologic characterization and antitumor effects of human monoclonal antibodies for carcinoembryonic antigen.
We generated fully human mAbs (HmAbs) to carcinoembryonic antigen (CEA) using the KM mouse, which carries a human chromosome 14 fragment containing the entire Ig H chain loci and human kappa L chain segments in the mouse genome. Forty-six hybridoma clones producing HmAbs to CEA were thus obtained by fusing the P3-U1 mouse myeloma cells with splenocytes of the KM mice immunized with CEA. Among them, 22 clones produced HmAbs that reacted with CEA but not with 3 other CEA-related cell adhesion molecule (CEACAM) family members, CEACAM1, CEACAM6 and CEACAM8. In 12 HmAbs examined, 8 were IgG4, 2 were IgG3, 1 was IgG2, and the other was IgG1. The affinity constants for CEA of these HmAbs were comparable to those of the previously prepared mouse anti-CEA mAbs (MmAbs). BIAcore analyses revealed that 1 and 2 of the 22 HmAbs react with 2 epitopes defined by MmAbs on the domain N and the domain A1 or B1 of CEA, respectively. In the presence of human complement in vitro, 2 HmAbs tested showed substantial cytotoxicity, namely, 50-65%, against CEA-expressing tumor cells. With human lymphokine-activated killer cells in vitro, 3 HmAbs tested exhibited 40-65% Ab-dependent cell-mediated cytotoxicity against the tumor cells. Moreover, one of the HmAbs induced a significant inhibition of tumor growth when administered to mice xenografted with the CEA-expressing cells. Considering their lack of immunogenicity to humans, these CEA-specific HmAbs may be useful for immunotherapeutic approaches as well as for immunodiagnosis.
Imakiire
Takayuki
T
Department of Biochemistry, Fukuoka University School of Medicine, Fukuoka, Japan.
Kuroki
Motomu
M
Shibaguchi
Hirotomo
H
Abe
Hironori
H
Yamauchi
Yasushi
Y
Ueno
Aruto
A
Hirose
Yumiko
Y
Yamada
Hiromi
H
Yamashita
Yuichi
Y
Shirakusa
Takayuki
T
Ishida
Isao
I
Kuroki
Masahide
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000627:therapeutic use*; D000912:Antibodies, Neoplasm / Q000276:immunology / Q000627:therapeutic use; D000918:Antibody Specificity / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity / Q000276:immunology; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D016513:Mice, SCID; D009101:Multiple Myeloma / Q000276:immunology / Q000378:metabolism; D013274:Stomach Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D014407:Tumor Cells, Cultured / Q000637:transplantation
D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D002272:Carcinoembryonic Antigen; D015815:Cell Adhesion Molecules; D000939:Epitopes; D007074:Immunoglobulin G