Molecular cloning of rat NK target structure--the possibility of CD44 involvement in NK cell-mediated lysis.
The nature of target molecules of natural killer (NK) cell-mediated lysis remains to be elucidated. As we previously reported, mAb 109 recognizes one of the tumor-associated antigens, designated as 109 antigen (Ag), expressed on the cell surface of rat fibrosarcomas W31 and W14, which are transformants of WFB (rat fetal fibroblast cell line) with H-ras oncogene. 109Ag was thought to be a target structure of NK cells since mAb 109 inhibited NK cell-mediated lysis against W31 and W14. Here, we demonstrate by molecular cloning that 109Ag is identical to rat CD44. Immunoprecipitation and immunoblotting studies also showed that mAb 109 and anti-rat CD44 mAb OX-50 recognize the same protein of W31 cell lysates with an 86 kDa molecular size. CD44 was suggested to be a target structure of NK cell-mediated lysis; however, rat CD44 cDNA transfection alone into CD44 null cell lines did not result in up-regulation of target cell susceptibility to NK cell-mediated lysis. Our results therefore indicated that CD44 may play a crucial role as one of the target structures in our rat fibrosarcoma system though the cell surface expression of CD44 alone does not affect NK susceptibility of the target cells.
Kanki
K
K
Department of Pathology, Sapporo Medical University School of Medicine, Hokkaido, Japan.
Torigoe
T
T
Hirai
I
I
Sahara
H
H
Kamiguchi
K
K
Tamura
Y
Y
Yagihashi
A
A
Sato
N
N
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D018076:DNA, Complementary; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D015870:Gene Expression; D018960:Hyaluronan Receptors / Q000235:genetics / Q000276:immunology*; D015151:Immunoblotting / Q000379:methods; D007694:Killer Cells, Natural / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008934:Mitogens / Q000494:pharmacology; D008969:Molecular Sequence Data; D011070:Poly I-C; D011233:Precipitin Tests / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D018960:Hyaluronan Receptors; D008934:Mitogens; D013755:Tetradecanoylphorbol Acetate; D011070:Poly I-C