ABSTRACT
In this study, we developed a rabbit polyclonal antibody to a fusion protein containing the envelope (env) transmembrane (TM) region from the human endogenous retroviral family, HERV-E. We used this reagent to document the expression of TM-related protein by Western blot in endothelial, colon and prostate carcinoma and seminoma cell lines and in peripheral blood mononuclear cells from a healthy donor. We detected a 58-kD protein (as compared to murine TM of 15 kD) that had specificity for the env-related antibodies of the polyclonal antiserum.
Subject(s)
Gene Products, env/analysis , Neoplasm Proteins , Neoplasms/chemistry , Retroviridae Proteins/analysis , Retroviridae , Viral Envelope Proteins/analysis , Adenocarcinoma/chemistry , Animals , Antibody Formation , Antibody Specificity , Colonic Neoplasms/chemistry , Endothelium/chemistry , Gene Products, env/immunology , Humans , Male , Prostatic Neoplasms/chemistry , Rabbits , Recombinant Fusion Proteins/analysis , Recombinant Fusion Proteins/immunology , Retroviridae Proteins/immunology , Seminoma/chemistry , Testicular Neoplasms/chemistry , Tumor Cells, Cultured/chemistry , Viral Envelope Proteins/immunologyABSTRACT
Tumor-induced immunosuppression by murine retrovirus-induced tumors and nonviral murine and human tumors has been shown to be mediated by the transmembrane (TM) envelope (env) protein p15E. This in vitro activity is inhibitable by anti-(murine)p15E antibodies, implying that a TM-like protein is produced by such tumors. The leading candidate genes that might encode such proteins in human tumors are human endogenous retroviral (HERV) sequences. We have utilized immunohistochemistry to determine what tissues may express HERV env proteins. We subcloned a restriction fragment from the putative TM human env gene of a type C-related HERV (clone-4-1) into a fusion protein gene construct. Using a rabbit polyclonal antiserum against the fusion protein, we observed staining in a variety of human tumor and nontumor tissues.
