- Volume 64, Issue 4, 1983

Most virus-specific polypeptides in cells productively infected with Marek’s disease virus (MDV) or herpesvirus of turkeys (HVT) possess cross-reactive antigenic determinants, although the two viruses have very little DNA homology. The cross-reactivity appeared to be more evident when [35S]methionine-labelled polypeptides were immunoprecipitated than when the [3H]glucosamine-labelled polypeptides were immunoprecipitated, suggesting that the glycoproteins of MDV and HVT may be less related in structure than other proteins. The major cross-reactive glycoproteins excreted into the culture mediums of MDV- and HVT-infected cells had molecular weights of 64000 (gp64) and 56000 (gp56) respectively.

We have recently reported isolation of a new human papilloma virus (HPVNF) from red plaques of a patient (NF) with epidermodysplasia verruciformis. The HPV DNA was molecularly cloned in Escherichia coli x1776 using plasmid pBR325. We have constructed a detailed physical map of the cloned DNA, which should be useful for examining the relationship of HPV and skin carcinoma.

Since endpoint titrations of scrapie material are costly and time-consuming, several workers have estimated titre from the correlation between the incubation period of the disease and the infectivity titre. However, we show here that the relationship between incubation period and titre cannot be assumed to be constant for all scrapie preparations. Our results indicate that sodium deoxycholate treatment of scrapie preparations does not reduce the titre, but can lengthen the incubation period by about 10 days. This is equivalent to a discrepancy of 1 log LD50 unit if the estimation of titre was based on the incubation period.

Using immune electron microscopy (IEM), low-level cross-reactions could be demonstrated between the surface antigens of hepatitis B and woodchuck hepatitis. However, immune complex formation was greatly enhanced by pre-exposure of the antigens to 0.5% deoxycholate. Cross-reaction between the core antigens and e antigens of both viruses was also confirmed by IEM as well as radioimmunassay. It appears that the woodchuck sera used in this study may well contain an anti-immunoglobulin akin to rheumatoid factor.