MOST OF THE VP1 UNIQUE REGION OF B19 PARVOVIRUS IS ON THE CAPSID SURFACE

B19 parvovirus is pathogenic in man and a vaccine is desirable. In con valescence after acute infection, the dominant humoral immune response is directed to the minor capsid protein called VP1, which differs fro m the major capsid protein by an additional NH2-terminal 227 amino aci ds. We have previously shown that this unique region contains multiple linear neutralizing epitopes. We produced seven recombinant B19 capsi ds that contained progressively truncated VP1 unique region sequences, each fused to a Flag peptide (AspTyrLysAspAspAspAspLys) at the NH2-te rminus. Capsids containing normal VP2 and truncated Flag-VP1 proteins and, in some cases, only truncated Flag-VP1 chimeric proteins, were an alyzed by ELISA, affinity chromatography, and electron microscopy usin g anti-flag monoclonal antibody. All regions examined showed binding t o anti-flag antibody in multiple assays, indicating that most of the V P1 unique region is external to the capsid and accessible to antibody binding. These results have implications for the design of a B19 parvo virus vaccine and the use of empty capsids for presentation of heterol ogous protein antigens. (C) 1995 Academic Press, Inc.