The measles virus (MV) strains with mutated hemagglutinin gene (ha) lost the capacity to infect its sensitive host cells (Vero cells), but it may infect the marmoset B-lymphoblastoid cell line B95a. From above, we can presume that there is a novel cellular receptor for those measles virus strains on B95a cells. Using the yeast two-hybrid system, we screened and cloned a novel gene-bip (B-lymphoblastoid interaction protein of marmoset) from B95a cell cDNA library, which encoded a protein interacting with measles virus hemagglutinin protein (Ha). The bip cDNA was 1540 base pairs in length and contained a unique open reading frame (ORF) of 1011 base pairs encoding a transmembrane protein of 337 amino acid residues. The primary structure of amino acids residue is predicted that the Bip comprised a hydrophobic transmembrane domain and a hydrophobic leader region. The researches about the deletion mutants showed that the deletion of transmembrane domain in Bip did not affect the interaction between Bip and Ha The measles virus (MV) mutant with mutated hemagglutinin gene (ha) lost the capacity to in sensitive its sensitive host cells (Vero cells), but it may infect the marmoset B-lymphoblastoid cell line B95a. From above, we can presume that there is a novel cellular receptor for those measles virus on B95a cells. Using the yeast two-hybrid system, we screened and cloned a novel gene-bip (B-lymphoblastoid interaction protein of marmoset) from B95a cell cDNA library, which encoded a protein interacting The biphase cDNA was 1540 base pairs in length and contained a unique open reading frame (ORF) of 1011 base pairs encoding a transmembrane protein of 337 amino acid residues. The primary structure of amino acids residue is predicted that the Bip comprised a hydrophobic transmembrane domain and a hydrophobic leader region. The researches about the deletion mutants showed that the deletion of transmembrane domain in Bip did not affect the interaction between Bip and Ha