Enzyme-linked immunosorbent assay in the diagnosis of Kilham rat virus infection in rats

An enzyme-linked immunosorbent assay (ELISA) was adapted and compared with the haemagglutination-inhibition (HAI) test for the serological diagnosis of Kilham rat virus (KRV) infection in rats. The assay is a solid phase, indirect method for the measurement of specific antibody. Test variables such as the amount of purified KRV for coating polystyrene microtitre plates, dilution of peroxidase conjugate, etc. were standardized for optimum results. Sera from both naturally and experimentally infected rats were examined, and the ELISA was found to be 5-10 times more sensitive for KRV serology. The kinetics of antibody development during experimental infection, as determined by ELISA, paralleled that of the HAI test and antibodies could be detected as early as 4 days after infection.

Effects of Kilham rat virus on natural killer cell-mediated cytotoxicity in brown Norway and Wistar Furth rats

Effects of Kilham rat virus (KRV) on selected aspects of the immune response of 2 strains of laboratory rats were studied. The Brown Norway rat and Wistar Furth rat were infected with KRV and serum antibody and interferon values and cytotoxic activity of natural killer cells were determined to assess the virus' effect on the rat's immune systems. Antibody values to the virus were increased in both strains after viral inoculation, and total antibody values were comparable in the 2 rat strains. Natural cytotoxicity was increased in Brown Norway rats 3 to 4 days after inoculation in contrast to a distinct depression for a period of 10 days in the Wistar Furth strain. Serum interferon was not measurable in either strain of rat. Seemingly, there is a distinct immune response to KRV in each rat strain and the cytotoxic activity response differs in these 2 strains of rats.

H-1 and X14 parvovirus antibodies in women with abortions or still-births

Antibodies against H-1 and X14 parvoviruses were found 13.71 and 9.14%, respectively, of 350 sera from women affected by repeated abortions or still-births. On the contrary, only 2.66 and 1.66% of 300 control sera were positive to the two viruses. The difference in the incidence of antibodies appears highly significant (p greater than 0.001). Therefore a possible role of the parvoviruses in inducing abortions or still-births in humans is suggested.

Human lymphoblastoid cells as hosts for parvoviruses H-1 and rat virus

A human T-cell line (Molt-4) was shown by viral hemagglutination and infectivity assays to support the replication of rat virus (RV) and H-1 virus. In addition, H-1 virus, but not RV, multiplied in two human B-cell lines, AV-1 and NC-37. The ability to bind radioactively labeled RV was demonstrated for each of the cell lines, but viral adsorption occurred to a greater degree with Molt-4 cells than with either AV-1 or NC-37 cells. After challenge with RV, virus-specific antigens were detected in cells of the B-cell lines by the indirect immunofluorescence technique. Infection of AV-1 or NC-37 cells by RV apparently results in an abortive cycle of virus replication. Differences among the three cell lines that might influence with H-1 virus or RV are discussed.

Development of sensitive methods for detection of latent Kilham virus infection of rats

The developed system of procedures, including preliminary selection of rats according to the presence of 19 S antibody in the blood serum, and the use of the most sensitive methods has increased considerably the incidence of detection of Kilham virus (KV) in organs of latently infected rats. To isolate and establish KV strains from the organs of rats in which the specific antigen was detected by immunofluorescence, at least 5-9 passages in rat embryo cell cultures or in newborn Syrian hamsters were required.