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Analytical Cellular Pathology
Volume 23 (2001), Issue 1, Pages 11-19

Investigation on Cell Proliferation with a New Antibody against Thymidine Kinase 1

Naining Wang,1 Qimin He,2 Sven Skog,2 Staffan Eriksson,3 and Bernhard Tribukait1

1Department of Oncology and Pathology, Karolinska Institute, Stockholm, Sweden
2Department of Oncology, KFC, Huddinge University Hospital, Sweden
3Department of Veterinary Medical Chemistry, Swedish University of Agricultural Science, Biomedical Center, Uppsala, Sweden

Received 15 February 2001; Accepted 10 May 2001

Copyright © 2001 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The cytosolic thymidine kinase 1 (TK1) is one of the enzymes involved in DNA replication. Based on biochemical studies, TK1 is activated at late G1 of cell cycle, and its activity correlates with the cell proliferation. We have developed a polyclonal anti‐TK1 antibody against a synthetic peptide from the C‐terminus of human TK1. Using this antibody, here we demonstrate the exclusive location of TK1 in the cytoplasm of cells. Cell cycle dependent TK1 expression was studied by simultaneous fluorescence staining for TK1 and bromodeoxyuridine, by using elutriated cells, and by quantitation of the amount TK1 in relation to the cellular DNA content. TK1, which was strongly expressed in the cells in S+G2 period, raised at late G1 and decreased during mitosis. The amount of TK1 increased three folds from late G1 to G2. TK1 positive cells were demonstrated in areas of proliferation activity of various normal and malignant tissues. The new anti‐TK1 antibody works in archival specimens and is a specific marker of cell proliferation.