Article: PDF OnlyModulation by interferon α and γ of the expression of a melanoma-associated antigen detected by autologous antibodyVlock, D. R.; Toporowicz, A.; Arnold, B.Author Information Brigham and Women's Hospital, Hematology–Oncology Division, 75 Francis Street, Boston MA 02115, USA. Tel: (+1) 617–732-6782; Fax: (+1) 617–732-5706 (D. R. Vlock). Division of Medical Oncology, Pittsburgh Cancer Institute, University of Pittsburgh, School of Medicine and VA Medical Center, University Drive C, Pittsburgh, PA 15240, USA. Tel: (+1)412–621-8722; Fax (+1) 412–683-2361. (A. Toporowicz, B. Arnold). Melanoma Research: July 1992 - Volume 2 - Issue 2 - p 105-114 Buy Abstract Interferons (IFN) are known to alter the expression of histocompatibility and tumour-associcated antigens. We have reported the isolation and purification of a 66-kD melanoma-associated antigen (MAA) that is recognized by the host. Competitive binding with MAA reduced autologous antibody binding to five melanoma cell lines, suggesting that a similar antigen is detected by other patients with melanoma. Nine melanoma cell lines were incubated for 3 days with 0.01–100 units/ml of interferon alpha (IFN-α) or interferon gamma (IFN-γ) and the maximum titre of autologous antibody reactivity was determined by protein A haemadsorption. Incubation with IFN-α or IFN-γ resulted in a decrease in maximum titre of autologous antibody reactivity directed against all melanoma cell lines. A 3-day Incubation of three melanoma cell lines with IFN-γ augmented the expression of HLA-DR, as has been reported by others. Incubation with spent media from autologous melanoma cells exposed to IFN-α inhibited autologous antibody binding less than control media from melanoma cells to which no IFN was added, indicative of decreased production or internalization of MAA. Conversely, incubation with spent media obtained after exposure to IFN-γ inhibited autologous antibody binding to a greater degree than control spent media, consistent with increased shedding of antigen. These results suggest that IFN-α and IFN-γ down-regulate the expression of MAA detected by autologous antibody by different mechanisms of action. © Lippincott-Raven Publishers.