A CD46CD[55-46] chimeric receptor, eight short consensus repeats long, acts as an inhibitor of both CD46 (MCP)- and CD150 (SLAM)-mediated cell-cell fusion induced by CD46-using measles virus

Function of bovine CD46 as a cellular receptor for bovine viral diarrhea virus is determined by complement control protein 1

The pestivirus bovine viral diarrhea virus (BVDV) was shown to bind to the bovine CD46 molecule, which subsequently promotes entry of the virus. To assess the receptor usage of BVDV type 1 (BVDV-1) and BVDV-2, 30 BVDV isolates including clinical samples were assayed for their sensitivity to anti-CD46 antibodies. With a single exception the infectivity of all tested strains of BVDV-1 and BVDV-2 was inhibited by anti-CD46 antibodies, which indicates the general usage of CD46 as a BVDV receptor. Molecular analysis of the interaction between CD46 and the BVD virion was performed by mapping the virus binding site on the CD46 molecule. Single complement control protein modules (CCPs) within the bovine CD46 were either deleted or replaced by analogous CCPs of porcine CD46, which does not bind BVDV. While the epitopes recognized by anti-CD46 monoclonal antibodies which block BVDV infection were attributed to CCP1 and CCP2, in functional assays only CCP1 turned out to be essential for BVDV binding and infection. Within CCP1 two short peptides on antiparallel beta strands were identified as crucial for the binding of BVDV. Exchanges of these two peptide sequences were sufficient for a loss of function in bovine CD46 as well as a gain of function in porcine CD46. Determination of the size constraints of CD46 revealed that a minimum length of four CCPs is essential for receptor function. An increase of the distance between the virus binding domain and the plasma membrane by insertion of one to six CCPs of bovine C4 binding protein exhibited only a minor influence on susceptibility to BVDV.

Co-purification of soluble membrane cofactor protein (CD46) and human herpesvirus 6 variant A genome in serum from multiple sclerosis patients

The association of human herpesvirus 6 (HHV-6) and multiple sclerosis (MS) has been supported by several immunological and molecular studies. Recently, membrane cofactor protein (CD46) has been identified as the cellular receptor for the A and B variants of HHV-6. Elevated levels of soluble CD46 (sCD46) have been reported in the serum and CSF of MS patients. The aim of this study was to investigate a possible correlation between elevated levels of soluble CD46 and the presence of serum HHV-6 DNA in MS patients. An immunoaffinity column comprised of immobilized monoclonal antibodies to CD46 was developed to isolate sCD46 from cell free body fluids of MS patients and controls. After immunoaffinity purification, DNA was extracted from anti-CD46 column eluates and subjected to PCR amplification. Of the 42 MS samples tested, 4 serum samples were HHV-6 positive, 3 of which were typed as HHV-6A. The co-purification of sCD46 and HHV-6 DNA from MS sera indicates that HHV-6 is tightly connected to its receptor, CD46, in the serum of MS patients.