No abstract

A panel of 23 monoclonal antibodies to the nucleocapsid protein of rabies virus was used to study the antigenic character of isolates of rabies virus from raccoons in the mid-Atlantic region of the United States. Comparison of the reaction pattern of these isolates with that of isolates of rabies virus collected from areas of major rabies outbreaks (skunk rabies in the midwestern United States, fox rabies in the northeastern United States, and raccoon rabies in the southeastern United States) suggests that this new epizootic originated with the transportation of rabid raccoons from the southeastern United States.

Rabies virus isolates from terrestrial animals in six areas of the United States were examined with a panel of monoclonal antibodies to nucleocapsid proteins. Characteristic differences in immunofluorescence reactions permitted the formation of four antigenically distinct reaction groups from the 231 isolates tested. The geographic distribution of these groups corresponded well with separate rabies enzootic areas recognized by surveillance of sylvatic rabies in the United States. Distinctive reaction patterns were also identified for viral proteins from four infected bat species, and identical patterns were found in eight isolated cases of rabies in terrestrial animals. These findings suggest that monoclonal antibodies can be used to study the prevalence, distribution, and transmission of rabies among wildlife species.

Monoclonal antibodies were produced from mice infected with Rickettsia akari (the etiologic agent of rickettsialpox) and evaluated for specificity in indirect fluorescent-antibody tests with 23 different rickettsial antigens. Of the nine antibodies that were evaluated, two were specific for R. akari and four reacted with R. akari and all other spotted fever group rickettsiae. The remaining three antibodies reacted with some, but not all, members of the spotted fever group. None of the antibodies reacted with typhus, scrub typhus, trench fever, or Q fever rickettsiae. Adding these antibodies to the list of available diagnostic reagents will facilitate identification of rickettsial diseases, particularly those caused by members of the spotted fever group, where the clinical presentations are similar and the etiologic agents are closely related antigenically.

A rapid and sensitive enzyme immunoassay is described for detecting rabies antibody in hybridoma culture fluids. Glass fiber filter disks were used to immobilize gamma-irradiated mouse neuroblastoma cells infected with street or laboratory strains of rabies virus. Bound rabies-specific antibody was detected by reaction with horseradish peroxidase-labeled goat anti-mouse immunoglobulin G. The assay was performed in a 96-well filtration device developed by Cleveland et al. (J. Clin. Microbiol. 15:402-407, 1982) for the typing of herpes simplex viruses. When partially disrupted cells were used, both internal and external viral antigens were available for reaction. The procedure is rapid (<4 h for completion) and requires only small amounts of fluid, and the gamma-irradiated antigen is noninfectious. When the procedure was used to screen 145 fluids from rabies-immune spleen-myeloma cell fusions, 132 were positive for rabies antibody. Other commonly used assays for the detection of rabies-specific antibody were less sensitive. Simultaneous analyses of many hybridoma fluids against a battery of street and laboratory strains of rabies virus are possible and allow rapid selection of useful monoclones.