Immunohistochemically defined lymphocyte function-associated antigen 1 (LFA-1) on an adenocarcinoma cell line is a distinct molecule from LFA-1 on leukocytes.
We previously reported that the immunohistochemically defined LFA-1 antigen (LFA-1-like antigen) was expressed on various exocrine tissues uninvolved with tumors in patients with malignant diseases using LFA-1 alpha-specific monoclonal antibodies (mAb) 2F12 and HVS6B6. In this study we investigated differences at the molecular level between LFA-1 on leukocytes and LFA-1-like antigen on MKN45.16, a subline derived from an adenocarcinoma line MKN45 that expresses a high amount of LFA-1-like antigen. LFA-1-like antigen was reactive to mAb 2F12 or HVS6B6, but not to any of the other five different LFA-1 alpha (CD11a)-specific or four LFA-1 beta (CD18)-specific mAb. mAb 2F12 immunoprecipitated a 200-kDa membrane protein (LFA-1-like antigen) from MKN45.16 cells, whereas it precipitated 180-kDa (LFA-1 alpha) and 95-kDa (LFA-1 beta) proteins from a monocytic cell line (THP-1) under both nonreducing and reducing conditions. The molecular difference was confirmed further by N-glycanase treatment of the immunoprecipitates. The isoelectric point of LFA-1-like antigen was 6.0, whereas those of LFA-1 alpha and LFA-1 beta were 6.0 and 4.7, respectively, by two-dimensional gel electrophoresis. Expression of LFA-1 alpha gene on MKN45.16 cells was not detected at the mRNA level by six different sets of LFA-1 alpha-specific oligonucleotides and reverse transcription-polymerase chain reaction. These results indicated that LFA-1-like antigen on an adenocarcinoma cell line was a distinct molecule from LFA-1 on leukocytes.
D000230:Adenocarcinoma / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007962:Leukocytes / Q000737:chemistry* / Q000201:enzymology / Q000276:immunology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis* / Q000235:genetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000032:analysis; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D014407:Tumor Cells, Cultured
D016169:Lymphocyte Function-Associated Antigen-1; D012333:RNA, Messenger