Hydroxyl Radical Damaged Thymidine-5’-Monophophate Presents Unique Epitopes for Cancer Antibodies

Rizwan Ahmad, Zafar Rasheed*, Rashid Ali
Department of Biochemistry, Faculty of Medicine, J.N. Medical College, A.M.U. Aligarh-202002, India

© 2009 Ahmad et al.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address Correspondence to this author at the Department of Pathology, Microbiology & Immunology, School of Medicine, University of South Carolina, 6439 Garners Ferry Road, Columbia, SC 29209, USA; Tel: +1216-650-9487; Fax: +1803-733-5828;E-mail:


Reactive oxygen species (ROS) plays an important role in carcinogenesis and hydroxyl radical (OH) contributes to the structural changes in DNA that characterize the cancer like phenotype. The role of hydroxyl radical (OH) damaged thymidine 5'-monophosphate (TMP) in cancer patients has been investigated in the present study. TMP was conjugated to bovine serum albumin (BSA), and then TMP-BSA conjugate was modified by hydroxyl radicals. Cancer patients (n = 99) were screened by direct binding ELISA for the detection of antibodies against native and ROS-modified conjugates and the results were compared with healthy age-matched controls (n = 29). High degree of specific binding by cancer serum antibodies towards ROS modified TMP-BSA conjugate, in comparison to unmodified conjugate (p<0.05) was observed. Healthy individuals showed negligible binding with either antigen. Competitive inhibition ELISA reiterates the direct binding results. Protein-A affinity purified IgG from cancer patients further substantiated the enhanced recognition towards modified conjugate as compared to unmodified conjugate. The present study clearly shows the perturbation in TMP-BSA conjugate by hydroxyl radical presenting unique neo-epitopes on TMP that might from one of the factors in antigen driven induction of antibodies in cancer patients.