Identification of an immunodominant peptide in the parvovirus B19VP1 unique region able to elicit a long-lasting immune response in humans

The immune response against parvovirus B19 is mainly directed against the t wo structural proteins, VP1 and VP2, The amino terminal half of the VP1 uni que region has been shown to elicit a dominant immune response in humans, m ore effective than other linear epitopes and also it has been seen to conta in significant neutralizing linear epitopes, Three overlapping recombinant peptides corresponding to amino acids 240 (VP1-A), amino acids 32-71 (VP1-B ), and amino acids 60-100 (VP1-C) of the VP1 unique region were produced by a procaryotic expression system. These peptides were used as antigens in a Western blot assay to detect specific immunoglobulin G (IgG) in serum samp les from blood donors of different age groups with documented signs of a pa st B19 infection. Fragment VP1-C appeared significantly immunodominant over the other peptides, reacting with specific IgG in 86% of serum samples. Th e fragment VP1-C corresponds to a sequence with a known neutralizing activi ty and seems able to elicit a long-lasting immune response because specific IgG were present in blood donors of all age groups. VP1-C would therefore appear to be an attractive candidate as a component of a subunit vaccine.