Identification of cross-reactive and serotype 2-specific neutralization epitopes on VP3 of human rotavirus

Abstract

The group A rotaviruses are composed of at least seven serotypes. Serotype specificity is defined mainly by an outer capsid protein, VP7. In contrast, the other surface protein, VP3 (775 amino acids), appears to be associated with both serotype-specific and heterotypic immunity. To identify the cross-reactive and serotypespecific neutralization epitopes on VP3 of human rotavirus, we sequenced the VP3 gene of antigenic mutants resistant to each of seven anti-VP3 neutralizing monoclonal antibodies (N-MAbs) which exhibited heterotypic or serotype 2-specific reactivity, and we defined three distinct neutralization epitopes on VP3. The mutants sustained single amino acid substitutions at position 305, 392, 433, or 439. Amino acid position 305 was critical to epitope I, whereas amino acid position 433 was critical to epitope III. In contrast, epitope II appeared to be more dependent upon conformation and protein folding because both amino acid positions 392 and 439 appeared to be critical. These four positions clustered in a relatively limited area of VP5, the larger of the two cleavage products of VP3. At the positions where amino acid substitutions occurred, there was a correlation between amino acid sequence homology among different serotypes and the reactivity patterns of various viruses with the N-MAbs used for selection of mutants. A synthetic peptide (amino acids 296 to 313) which included the sequence of epitope I reacted with its corresponding N-MAb, suggesting that the region contains a sequential antigenic determinant. These data may prove useful in current efforts to develop vaccines against human rotavirus infection.

Survey on the distribution of the gene 4 alleles of human rotaviruses by polymerase chain reaction

“…As an alternative, genetic analysis to identify the gene 4 allele seems to be effective for predicting P serotype, because the correlation between gene 4 alleles and P serotypes of HRV is well established. The amino acid sequences of the VP8 fragment of VP4 carry strain-specific or P serotype-specific epitopes, while cross-reactive neutralization epitopes are located on the VP5 fragment of VP4 [23][24][25]. PCR, using the nucleotide sequences in the hyper-variable region on the VP8 which encode P serotype-specific epitopes, is appropriate for predicting P serotype which corresponds to gene 4 allele.…”

“…The PCR was applied to HRV in stool specimens from patients with diarrhoea. In a total of 199 stool specimens positive for group A HRV collected in Japan and Thailand, the gene 4 allele of 194 (97 5 %) samples could be classified; 165 were grouped to PIA gene 4 allele, 24 were PIB gene 4 allele, 2 were P2 gene 4 allele, and 1 was P3 gene 4 allele ( Table 2). Figure 2 shows representative results.…”

Evidence of conserved epitopes in variable region of VP8* subunit of VP4 protein of rotaviruses of P[8]-1 and P[8]-3 lineages

“…Titration of neutralizing antibodies. Human rotavirus strain Wa (kindly provided by Carlos F. Arias, IBT-UNAM, Mexico) was propagated in MA104 cell as described (Taniguchi et al, 1998). The presence of NtAb to rotavirus strain Wa in the sera of children was determined using the immunochemical focus reduction neutralization test (Arias et al, 1987).…”

Immune response to rotavirus VP4 expressed in an attenuated strain ofShigella flexneri

“…While antibodies to either of the outer capsid proteins of rotavirus, viral protein (VP) 4 or VP7, have been demonstrated to protect against disease [6], VP4 has been shown to generate a heterotypic immune response [7,8]. VP4 is involved in viral attachment to the host cell.…”