ABSTRACT
Abstract Endogenous retroviruses (ERVs) are remnants of retroviral infections. ERVs preserve functions of exogenous retroviruses to various extents. ERVs are both parasites and symbionts. Although the most pathogenic elements are eliminated by selection, some
pathogenicity may remain. Some recently endogenized elements of mice and cats are known to cause disease. The situation in humans is less certain. Diseases where a role for ERV s has been discussed are multiple sclerosis, schizophrenia, diabetes, systemic lupus erythematosus, seminoma, malignant melanoma, preeclampsia and azoospermia. Several pathogenic mechanisms have been implicated: Antigenic mimicry, immune dysregulation, receptor interference, growth stimulation by cis-or transactivation, loss of physiological functions mediated by retroviral genes, and gene loss by illegitimate recombination are among them.
