Abstract: A genomic retroviral nucleic material, in an isolated or purified state, at least partially functional or non-functional, wherein the genome comprises a reference nucleotide sequence selected from the group including sequences of SEQ ID NOs: 1-15, their complementary sequences, and their equivalent sequences, in particular, nucleotide sequences having, for every series of 100 contiguous monomers, at least 70% and preferably at least 90% homology with the sequences of SEQ ID NOs: 1-15.

Abstract: The present invention concerns an in vitro method for determining, from a biological sample, the response to a patient suffering from rheumatoid arthritis to a treatment directed against a cytokine involved in the inflammatory process of the disease, characterized in that it consists in measuring the expression of the gene encoding synoviolin.

Abstract: A method for detecting the expression of a polypeptide in cells and for detecting the interaction between a polypeptide and cells, ex vivo or in vitro, wherein the polypeptide is selected from the group consisting of: a peptide comprising the cyt domain of the envelope protein of the human endogenous retrovirus, HERV-W; a peptide comprising amino acids 448-538 of SEQ ID NO: 1; and a peptide comprising a sequence having, for any series of 20 amino acids, at least 80% identity with amino acids 448-538 of SEQ ID NO: 1. Detection is established by the fusogenic power of the polypeptide, which is demonstrated by syncytia formation.

Abstract: The invention concerns a genomic retroviral nucleic material, in an isolated or purified state, at least partially functional or non-functional, wherein the genome comprises a reference nucleotide sequence selected from the group including sequences of SEQ ID NOs: 1-15, their complementary sequences, and their equivalent sequences, in particular, nucleotide sequences having, for every series of 100 contiguous monomers, at least 70% and preferably at least 90% homology with the sequences of SEQ ID NOs: 1-15. The invention also concerns the application of this material.