Preparation of a neutralizing monoclonal antibody specific to serotype 8 rotavirus strains with a super-short RNA pattern.

Extensive cross-neutralization tests have identified seven serotypes of rotavirus. Recently, it has been reported that several human strains (69M, B37 and B38) with a super-short RNA pattern carry new serotype specificity (serotype 8). By using the strain 69M as an immunizing antigen, we prepared a neutralizing monoclonal antibody (designated 69M-2D). In neutralization tests using 18 human and two animal rotavirus strains with different serotype specificities, the 69M-2D antibody was found to neutralize only serotype 8 strains. Also, in an enzyme-linked immunosorbent assay (ELISA), the antibody reacted exclusively with the serotype 8 strains. Thus, the reactivity pattern of the 69M-2D antibody was serotype 8-specific. This antibody should be useful as another reagent for serotyping rotaviruses by ELISA.

Determination of subgroup, serotype and electropherotype of human rotaviruses obtained from diarrheic patients in the Philippines.

A total of 40 rotavirus specimens obtained from infants with acute gastroenteritis in Metro Manila, Philippines, were analyzed for their subgroup and serotype specificities and RNA electropherotype. A half (50%) of the specimens contained subgroup I human rotaviruses (HRVs), while 45% of them contained subgroup II HRVs. All subgroup II HRVs were determined to be serotype 1, except one specimen belonging to serotype 3, by an enzyme-linked immunosorbent assay with serotype specific monoclonal antibodies. However, serotype specificity of all subgroup I specimens failed to be determined. In polyacrylamide gel electrophoresis, RNAs extracted from HRVs of either subgroup showed long electropherotype. At least two electropherotypes were distinguished in subgroup I viruses, while five different patterns of viral RNA were found in subgroup II viruses.