Human laminin binding protein as a cell receptor for the tick-borne encephalitis virus

Abstract

Summary We propose an approach to obtain the cell receptor for the tick-borne encephalitis (TBE) virus by affinity chromatography using polyclonal antiidiotyping antibodies (AlAbs) as antireceptor antibodies. The purified fraction of the cell receptor contains four polypeptides with molecular weights of 43, 67, 110, and 210 kDa. Polyclonal AlAbs interacted only with the 67 kDa protein in immunoblotting. The molecular size of the 67 kDa protein suggested that it is the nonintegrin laminin binding protein (LBP). Using the polymerase chain reaction and appropriate primers, the amplified fragments, containing the gene of the human laminin binding protein, were cloned from the RH cells; a gene-engineering product of the recombinant laminin binding protein was developed. The highly purified recombinant LBP interacted with the native protein E of the TBE virus and also competed with monoclonal antibody for interaction with protein E. The affinity of the interaction of the recLBP with protein E of the TBE virus was estimated to be 0.5–5 x 10 7 M ‡1 .