Age-related reduction of antibody response against the human endogenous retrovirus K envelope in women

// Hyoung Jin Kim 1, * , Byung-In Moon 2, * , Jun Woo Lee 2 , Seung Cheol Kim 3 , Hong-Jin Kim 1 1 Laboratory of Virology, College of Pharmacy, Chung-Ang University, Dongjak-Gu, Seoul 06974, South Korea 2 Breast and Thyroid Cancer Center, Ewha Womans University College of Medicine, Yangcheon-Gu, Seoul 07985, South Korea 3 Department of Obstetrics and Gynecology, Ewha Womans University College of Medicine, Yangcheon-Gu, Seoul 07985, South Korea * These authors have contributed equally to this work Correspondence to: Hong-Jin Kim, e-mail: hongjink@cau.ac.kr Keywords: human endogenous retrovirus K, envelope, breast cancer, cervical cancer, age, Gerotarget Received: November 16, 2015 Accepted: January 29, 2016 Published: February 10, 2016 ABSTRACT In the present study, the correlation between the antibody response against human endogenous retrovirus K (HERV-K) envelope and human age was investigated. Antibody levels were compared in groups in their 20s (n = 25), 30s (n = 39), 40s (n = 68), 50s (n = 32), and 60s and over (n = 25), which included healthy individuals and breast cancer and/or cervical cancer patients. It appeared that both IgM and IgG responses against the HERV-K envelope fell with increasing age. There were no differences in anti-HERV-K envelope antibody levels between healthy individuals and cancer patients. Therefore, our results indicated that the anti-HERV-K antibody levels cannot be considered as cancer-specific marker. Also, IgG1 appeared to be the predominant subtype in the reduction of the IgG response by age. Receiver operating characteristic curves of anti-HERV-K envelope IgM levels indicated that the groups of people in their 20s or 30s could be distinguished from those in their 40s, 50s or 60s and over with satisfactory sensitivity and specificity. These findings indicate that the serum antibody level of HERV-K envelope is a critical parameter reflecting person’s age.