Physico-chemical characterization of hamster interferon

Generation and purification of highly specific antibodies for detecting post-translationally modified proteins in vivo

Post-translational modifications alter protein structure, affecting activity, stability, localization and/or binding partners. Antibodies that specifically recognize post-translationally modified proteins have a number of uses including immunocytochemistry and immunoprecipitation of the modified protein to purify protein-protein and protein-nucleic acid complexes. However, antibodies directed at modified sites on individual proteins are often nonspecific. Here we describe a protocol to purify polyclonal antibodies that specifically detect the modified protein of interest. The approach uses iterative rounds of subtraction and affinity purification, using stringent washes to remove antibodies that recognize the unmodified protein and low sequence complexity epitopes containing the modified amino acid. Dot blot and western blot assays are used to assess antibody preparation specificity. The approach is designed to overcome the common occurrence that a single round of subtraction and affinity purification is not sufficient to obtain a modified protein-specific antibody preparation. One full round of antibody purification and specificity testing takes 6 d of discontinuous time.

Current report on the interferon program at Roswell Park Memorial Institute

An overview of the interferon program at Roswell Park Memorial Institute (RPMI), is presented. This program encompasses three interrelated areas of research and new drug development: (a) basic research on purification and characterization of animal and human interferons (leukocyte, fibroblast, and immune); (b) large scale manufacture and preclinical testing of human fibroblast interferon (HFIF); and (c) clinical trials with HFIF to determine its safety of administration as well as antiviral, antitumor, and immunomodulatory activities in patients with neoplastic or viral disease. The antitumor effect of HFIF produced at RPMI as assessed by intralesional injection of various metastatic nodules resulted in an overall 71% local response. Phase I studies in 13 patients demonstrated that HFIF can be administered safely by the subcutaneous, intramuscular, and intravenous routes in doses up to 25 million units per day without any serious untoward effects. Intrathecal administration of HFIF into patients with CNS leukemia was also well tolerated. Pharmacokinetic studies indicated significant levels of HFIF in serum and cerebrospinal fluid after intravenous and intrathecal administration, respectively. Coincidental with the HFIF systemic administration during the Phase I trials, favorable responses in several laboratory, immune, and clinical parameters were observed. These results provide the rationale for conducting phase II and phase III clinical trials with HFIF produced at RPMI.