Development of a monoclonal antibody specific for serotype 3 rotavirus strains

Monoclonal antipeptide antibodies recognize epitopes upon VP4 and VP7 of simian rotavirus SA11 in infected MA104 cells

To study morphogenetic events of rotavirus SA11-infected MA104 cells with strictly defined reagents we produced monoclonal antibodies against synthetic peptides from both outer capsid proteins VP4 (aa residues 228-241: QNTRNIVPVSIVSR) and VP7 (aa residues 319-326: SAAFYYRV) of simian rotavirus SA11. Two of the selected monoclonal antibodies proved to be reactive with determinants of SA11-infected MA104 rhesus monkey kidney cells, with purified SA11 as well as with the particular peptides used for immunization. The anti-VP4 antibody had a demonstrable neutralizing titer of 200 (50% focus reduction) whereas the anti-VP7 MuMAb revealed no detectable neutralizing activity. In peptide-inhibition experiments, the corresponding peptide inhibited its MuMAb whereas the noncorresponding peptide had no effect on antibody binding to intracellular viral antigen. Localization of VP7 was preceded by VP4 as shown by immunofluorescence microscopy.

Polypeptide specificity of antiviral serum antibodies in children naturally infected with human rotavirus

Reassortants between serotype 3 SA11 and serotype 6 NCDV rotaviruses were used to determine the relative amounts of serum-neutralizing antibody to VP4 and VP7 of serotype 3 SA11 rotavirus in children after natural rotavirus exposure. Sera from Ecuadorian children of a population-based study and sera from children of a hospital-based study in Germany (excluding diarrhea patients) demonstrated high titers of VP7-specific but only low titers of VP4-specific antibodies. In contrast, paired sera from German children hospitalized with a symptomatic primary rotavirus gastroenteritis demonstrated a titer increase to VP4 more frequently than to VP7 protein by neutralization test and immunoblotting. For these rotavirus patients, we provided, previously, direct evidence for the development of cross-neutralizing antibodies.

A synthetic peptide corresponding to the cleavage region of VP3 from rotavirus SA11 induces neutralizing antibodies

Antibodies were elicited in rabbits by immunization with the synthetic tetradecapeptide Gln-Asn-Thr-Arg-Asn-Ile-Val-Pro-Val-Ser-Ile-Val-Ser-Arg, corresponding to amino acids 228 to 241 of SA11-VP3. Protein specificity of the antipeptide serum is demonstrated. The antipeptide serum revealed neutralizing activity directed against SA11 in a neutralization assay. Human rotavirus strains Wa, S2, and Hochi and bovine strains NCDV and UK were not neutralized, demonstrating the strain-specific neutralizing activity of the raised antipeptide serum. Upon immune electron microscopy, aggregation of SA11 particles was observed.

Three amino acids of a heptapeptide-induced antibody are responsible for recognition of SV40 structural proteins

Antibodies were elicited against the heptapeptide Asp-His-Lys-Val-Ser-Thr-Val. The sequence of the heptapeptide corresponds to amino acid residues 105-111 of Simian Virus 40 (SV40) structural protein VP2. The antipeptide antibodies recognize VP2 and amino acid sequence Asp-His-Lys (193-195) in VP1 at different degrees of denaturation. Inhibition experiments were performed with the heptapeptide as well as with the tripeptide Asp-His-Lys. Using this model system, the specificity and selectivity of peptide-induced antibodies can be demonstrated with a resolution of a single amino acid.