Identification and mapping of neutralizing epitopes of human parvovirus B19 by using human antibodies

Abstract

We identified and mapped the regions responsible for neutralization in the human parvovirus B19 structural protein by using region-specific human antibodies derived from seropositive blood donors. The region-specific antibodies were purified by using affinity columns coupled with synthetic peptides of the hydrophilic regions including the s-turn structure deduced by the predicted secondary structure of VP2. Fifteen highly specific antibodies against the synthetic peptides were obtained. Ten of them were able to precipitate the radiolabeled virus. Six of them proved to be able to protect the colony-forming unit erythroid cells in human bone marrow cell cultures from injury by the virus. The sequences recognized by the six neutralizing antibodies were sites corresponding to amino acids 253 to 272, 309 to 330, 325 to 346, 359 to 382, 449 to 468, and 491 to 515 from the amino-terminal portion of VP2. These observations suggest that the neutralizing epitopes were distributed in the region from amino acid 253 in the amino-terminal portion of VP2 to the carboxyl terminus of VP2.

Mapping Antigenic Epitopes on the Human Bocavirus Capsid

“…As observed for the HBoV1-specific MAbs, the 2-/5-fold wall and 3-fold protrusions are hot spots for the majority of the antigenic footprints of other parvoviruses, including the AAVs, Aleutian mink disease virus (AMDV), B19, and canine parvovirus (CPV), and utilize residues within VR-I, VR-III, VR-IV, VR-V, VR-VI, and VR-VIII ( Fig. 8) (62)(63)(64)(65)(66)(67)(68)(69)(70). For example, residues within VR-I and VR-III are important for serotype-specific antibody interactions for the AAVs, including the AAV1-ADK1a, AAV2-A20, AAV2-D3, AAV5-ADK5a, and AAV5-3C5 antibody interactions.…”

Human Parvovirus B19 and Blood Products

“…In most individuals infection results in seroconversion with the resulting neutralising IgG antibodies affording life-long protection from re-infection [4]. Such antibodies are directed at a variety of neutralising epitopes on VP-1 and VP-2, and current vaccine developments are based on this knowledge [5][6][7]. The non-structural proteins have been shown to be directly cytotoxic, and may explain the cytopathic effects of B19 on cell types non-permissive for replication [8,9].…”

Four putative subtypes of human parvovirus B19 based on amino acid polymorphism in the C-terminal region of non-structural protein

“…VP2 protein is the major capsid protein and has epitopes recognized by a neutralization antibody. Sato et al [1991] identified the neutralizing epitopes using a CFU-e assay with affinity column purified human antibodies; they showed that the neutralizing epitopes were distributed in the region from amino acid 253 in the amino-terminal portion of VP2, with peak neutralization activity in amino acids 325-345. A mutation of amino acid 310 was also found in this region, but it was outside of the peak.…”

“…Several methods have been established to detect the B19 virion or its genome, including double immunodiffusion [Cossart et al, 1975], countercurrent immunoelectrophoresis [Cossart et al, 1975], enzyme immunoassay [Sato et al, 1991], radioimmunoassay , dot blot hybridization [Anderson et al, 1985;Clewly, 1985], and PCR [Clewly, 1989;Koch and Adler, 1990]. These methods, however, are not applicable for mass donor screening at blood centers.…”