Geographical prevalence of two types of Epstein-Barr virus.

The Jijoye EBV strain is characterized by a substitution of 1.8 kb in the C-terminal part of the EBNA 2 gene compared to B95-8 or M-ABA virus. This made it possible to construct hybridization probes specific for M-ABA (type A) and Jijoye viruses (type B), which have been used to type the EBV genomes in 38 spontaneously established cell lines. Type A is more prevalent being found in 31 of 38 cases; type B virus was found in five cell lines (Jijoye, LY 67, QIMR-GOR, BL 16, and BL 29); and two cell lines, Daudi and EB-3, contained neither the M-ABA- nor the Jijoye-specific sequences. EBV type B appears to be less ubiquitous, since all type B isolates, including AG 876 virus, originated from Central Africa, La Réunion, and New Guinea. All the other cell lines, carrying EBV type A, were established from patients from Central Africa (4), North Africa (7), New Guinea (1), and Asia (6) and from white individuals (13). The restricted geographical localization of EBV type B in parts of the southern hemisphere and its similarity to herpesvirus papio (T. Dambaugh, K. Hennessy, L. Chamnankit, and E. Kieff (1984) Proc. Natl. Acad. Sci. USA 81, 7632-7636) could suggest that such viruses may have evolved by recombination of EBV with a related Old World monkey virus, alternatively, evolution of virus variants within the human species also being conceivable.

A putative transforming gene of Jijoye virus differs from that of Epstein-Barr virus prototypes.

The P3HR-1 strain of Epstein-Barr virus (EBV), a nontransforming clonal derivative of Jijoye (EBV), is characterized by a deletion of 6.6 kb involving part of the BamHI-W repeats and the adjacent region including the NotI repeats. In the transforming parental Jijoye virus this region differs from the corresponding regions in B95-8 or M-ABA virus. The HindIII-B fragments which carry this region from both Jijoye and prototype M-ABA (EBV) viruses have been cloned and subclones have been constructed which contain the left-hand part of HindIII-B from the HindIII to the BglII site (BglII-delta C fragment). By restriction enzyme analysis the inserts were found to be of equal size (6.3 kb) but to differ in their restriction enzyme pattern. Heteroduplexes formed under stringent conditions in the presence of T4 gene 32 protein revealed a substitution loop of 1750 +/- 200 nucleotides. Heteroduplex formation under nonstringent conditions showed that the substituted sequences are partially homologous to each other, with the regions of nonhomology confined to three distinct areas of 100 to 200 nucleotides. The partial homology observed between both regions indicates that they have evolved from a common ancestor. By hybridization of a Jijoye virus subclone containing only sequences of the substituted region to Northern blots a 2.8-kb polyadenylated transcript was detected indicating that the substituted region is expressed in Jijoye cells.

Latent herpesvirus infection of testes and spinal ganglia of turkeys with semen abnormalities.

The present study confirms that herpesviruses (LF) previously isolated from testes and buffy coat cells of male turkeys with semen abnormalities establish a latent infection in testicular cells. These experiments also present the first evidence that these herpesviruses are harbored latently in cells of spinal ganglia. One-week-old turkeys were inoculated with either the LF isolates or the prototype turkey herpesvirus FC 126; allowed to mature sexually through one breeding season and necropsied at one year of age. Persistent infections with all viral isolates were confirmed by repeated reisolation of the viruses from buffy coat cells and the development of specific precipitating antibodies. The herpesviruses were also isolated from several tissues by cocultivation on primary chick kidney cells. Primary testicular cells required subcultivation for the induction of viral replication. Latent viruses were demonstrated by in vitro explanation of testicular and spinal ganglion biopsies which, at the time of explanation, contained no detectable infectious virus, viral antigens or particles. After prolonged in vitro explanation of explants of testes and spinal ganglia tissue yielded infectious virus and viral antigens and particles were identified in outgrowing explant cells.

Cell-mediated immunity in Marek's disease: cytotoxic responses in resistant and susceptible chickens and relation to disease.

Two experiments were conducted to study the cell-mediated cytotoxicity of peripheral blood leukocytes (PBL) from chickens inoculated with Marek's disease virus (MDV) against a Marek's disease-derived lymphoblastoid cell line (MSB-1) and to associate the cytotoxicity with incidence of disease. In experiment I, moderately susceptible random-bred, specific-pathogen-free chickens were inoculated with MDV (group 1), vaccinated with a herpesvirus of turkeys (HVT) and inoculated with MDV (group 2), vaccinated with HVT and inoculated with chicken kidney cells (CKC; group 3), and inoculated with CKC only (group 4). Cytotoxic activity in the PBL was detected initially during the first week after MDV inoculation and periodically throughout the observation period (groups 1, 2, and 3). Throughout the observation period, the magnitude of cytotoxic activity was similar in PBL from groups 1 and 2 chickens. The PBL from both surviving and fatally infected chickens (groups 1 and 2) were similarly cytotoxic when sampled during the first 16 days after MDV inoculation. In experiment II, inbred genetically susceptible (line 7) and resistant (line 6) chickens were used. Cytotoxic activity of PBL of significantly greater magnitude was associated with a lower mortality or incidence of gross lesions (or both) in MDV-inoculated line 6 (group B) and HVT-vaccinated and MDV-inoculated line 7 (group C) chickens compared with activity of PBL from MDV-inoculated line 7 (group A) chickens. The cytotoxic activity of PBL from individual inbred chickens did not correlate with the outcome of the infection.

Cell-mediated immunity in Marek's disease: correlation of disease-related variables with immune responses in age-resistant chickens.

A sequential study of cytotoxic and mitogen stimulation responses of peripheral blood leukocytes (PBL) after inoculation with Marek's disease (MD) virus was done with the 7 x 15 chickens at 2 weeks of age (group 1) and at 12 weeks (group 3). Control groups were inoculated with chicken kidney cells at 2 weeks of age (group 2) and 12 weeks (group 4). During an 8-week observation period, morbidity and mortality were greater in group 1 chickens than in group 3 chickens. The cytotoxic response of PBL against an MD tumor cell line (MSB-1) was greater during the first 2 weeks after chickens in group 3 were inoculated than in group 1 chickens. Correlations did not exist between cell-mediated cytotoxic responses and severity of disease for individual group 1 chickens. However, PBL fo group 3 chickens that developed gross lesions of MD had reduced cytotoxic activities after an initial activity equal to, or greater than, the activities of chickens that survived without gross lesions. Phytohemagglutinin stimulation of PBL was depressed in both groups during weeks 1 to 3 after inoculation. Group 3 chickens had higher virus titers in PBL than group 1 chickens during weeks 1 to 3 after inoculation. The titers subsequently decreased below those for group 1 during the remainder of the experiment.

Ultrastructural studies of semen abnormalities and Herpesvirus associated with cultured testicular cells from domestic turkeys.

Abnormal cells and macrophages found in white and yellow turkey semen were studied by electron microscopy. Yellow semen contained many abnormal cells, most of which were large and round or smaller and ellipsoidal. It was concluded that they were aberrant spermatids, with differentiation being more complete in the smaller cells. Only a few cells of the smaller type were detected in normal white semen. Macrophages were occasionally seen in white semen but were numerous in yellow semen. Phagocytic vacuoles of these cells contained structural elements of spermatozoa and abnormal spermatids. Virus particles were not detected in any of the seminal cells observed. Ultrastructure studies of cultured testicular cells obtained from several of the turkeys examined showed the presence of intranuclear Herpesvirus particles in germinal cells. Macrophages from the testicular cultures seldom were seen with intranuclear Herpesvirus, although these cells commonly were found with Herpesvirus particles and cellular debris contained within phagocytic vacuoles.

Lyophilization of cell-free Marek's disease herpesvirus and a herpesvirus from turkeys.

Cell extracts of the JM and GA strains of Marek's disease herpesvirus and the FC 126 strain of turkey herpesvirus were lyophilized with various stabilizers. Much higher virus titers were obtained with stabilizer than without stabilizer. Titers increased even further in the case of the Marek's disease virus strains by the addition of a chelating agent, disodium ethylenediaminetetraacetate.