Abstract: Scrapie brain homogenate was mixed with mouse peritoneal macrophages in vitro. After 2 h of incubation at 37 degrees, a portion of the scrapie infectivity was associated with macrophages. In contrast, very little infectivity was associated with kidney cells that had been exposed to scrapie brain homogenate. After incubation of the scrapie brain homogenate-macrophage mixture at 4 degrees rather than 37 degrees, a reduced quantity of infectivity was associated with the macrophages. These result show that in vitro incubation, the scrapie agent was associated with macrophages, and the data suggest that phagocytic activity was involved.

Abstract: Murine lymphocyte hybridomas which produce neutralizing or non-neutralizing monoclonal antibodies to different type 1, 2 or 3 poliovirus strains were isolated. The majority of these monoclonal antibodies reacted with antigenic determinants present on different polio-virus strains of the same type. However, hybridomas producing monoclonal antibodies specific for each of the three Sabin vaccine strains were also generated.

Abstract: Four juvenile laryngeal papillomas (JLPs) were examined for papillomavirus genus-specific structural antigens and polynucleotide sequences employing reagents derived from bovine papillomavirus type 1 (BPV-1). Three of four JLPs contained intranuclear antigens in the granular layer of differentiating epithelial cells of formalin-fixed, paraffin-embedded papillomas assayed by the peroxidase-antiperoxidase reaction using an antiserum prepared against purified detergent-disrupted BPV-1. Examination of these JLPs for viral sequences indicated two tumor DNA preparations contained polynucleotide sequences which hybridized to an in vitro labeled BPV-1 DNA probe under nonstringent conditions. These sequences were detectable after gel electrophoresis and immobilization of restriction-endonuclease-digested JLP DNAs onto nitrocellulose membranes. Specific hybridization of probe to digested JLP DNA was visualized as bands in autoradiograms coincidental with open circular and linearized papillomavirus DNA. Hybridization was extensively reduced when JLP DNA preparations were prehybridized to an unlabeled papillomavirus DNA heterologous to the probe. These results provide direct evidence for the association of a papillomavirus in JLP.

Abstract: Negative-contrast electron microscopy of purified rotavirus particles reveals two particle types: single-shelled and double-shelled particles. The relationship of these particle types, seen by negative staining, to the enveloped and various types of nonenveloped particles seen in thin sections of virus-infected cells was determined. Thin-section and negative-contrast electron microscopic analyses were performed on cell lysates from simian rotavirus. SA11-infected cells and on highly purified double- and single-shelled particles. In thin sections, double-shelled particles appeared as smooth-edged ovals containing dense nucleoids, whereas single-shelled particles had ragged edges and threads of material extending from their centers. The majority of nonenveloped particles seen in thin sections of infected cells were identified as double-shelled particles. Enveloped particles showed typical membrane structure and were observed rarely in crude rotavirus stocks, although they constitute about 10% of the particles within infected cells. It is hypothesized that the enveloped form is a transient one and the envelope is lost in the endoplasmic reticulum of the host cells. Finally, the 50-55 nm type IV particles seen within lysosome-like bodies in infected cells were identified as subviral particles formed from input virions.

Abstract: Fv-1 gene-specific resistance to eco tropic murine retro viruses can be transferred to permissive cells with RNA prepared from restrictive cells. The active RNA has a sedimentation coefficient of 20–2

Abstract: The baculovirus, Heliothis zea nuclear polyhedrosis virus (HzSNPV), was grown in the H. zea cell line, IPLB-1075. Light microscopy observations showed that 95% of inoculated cells had CPE by 6 days postinoculation (p.i.). Growth curves of intracellular and extracellular virus showed that maximum titers (TCID50 units) were reached 3-4 days p.i. Studies on HzSNPV morphogenesis revealed that ultrastructural events were typical of baculovirus replication in vitro. EcoRI restriction enzyme analyses of viral DNA produced in larvae and in cell culture were identical and indicated that this virus was HzSNPV.

Abstract: Varicella-zoster virions present in infected cells or in a cell-free state were freeze-dried without loss of structural integrity or infectivity. Generally, yields of > 5 logio foci/ml (infected cells

Abstract: Exposure of several spontaneously transformed human lymphoid cell lines to attenuated and virulent types 1 and 2 poliovirus strains led to an initial sharp increase in virus titer followed by a persistent infection. Virus was present as late as 80 passages after infection. The morphology, cell count and viability of virus- and mock-infected cells were similar. Approximately 1% of the cells scored as infectious centers, and the cultures could be cured by specific antiserum. Virus produced during persistent infections initiated with a virus that readily forms plaques at 40 degrees, Mahoney virus, showed an increase in temperature sensitivity and a decrease in plaque size.

Abstract: Equine infectious anemia virus (EIAV) was successfully inoculated onto cell cultures of canine and feline origin, resulting in chronic infections in these cultures. Infection of equine cell cultures, which were the previous sole in vitro source demonstrated for virus production, was also performed for comparative purposes. Determination of the nature of the virus produced in the heterologous as well as the equine cells was accomplished in several ways. SDS-PAGE of purified virus from the different cell lines indicated very similar protein composition. Immunological identity was observed in gel diffusion tests employing an antiserum to the major core protein (p24) of equine-derived EIAV. Competition radioimmunoassays also indicated similar antigenicity in the viruses derived from the several cell lines. Strong relatedness was further demonstrated by hybridization of viral RNAs to EIAV complementary DNA. These data indicate that EIAV has an amphotropic cell culture host range and that the viruses isolated from the permissive lines were similar.

Abstract: 59 sera of 10 immunosuppressed renal allograft recipients who experienced recurrent cytomegalovirus (CMV) infection were analyzed by enzyme-linked immunosorbent assay (ELISA) for CMV IgA antibodies and by the complement-fixation (CF) test. A significant rise of CF titer was evident 4-53 weeks post-transplantation. 9 patients produced CMV IgA in high titers at about the time of CF antibody rise was observed. 1 patient did not produce IgA antibodies to CMV. In 3 of the 9 patients, specific CMV IgA antibodies were detected before the rise if CF titer was demonstrated. CMV IgA antibodies were found to persist for as long as 6 weeks post-transplantation. The potential application of ELISA detection of CMV-specific IgA antibodies as an early indication of CMV infection in kidney transplant patients is discussed.

Abstract: Five plant rhabdoviruses fall into two groups based on the patterns produced by their dissociated virion proteins when separated electrophoretically. Lettuce necrotic yellows virus (LNVY) and Sonchus virus (SV) virions contained only one M protein and NS protein. Sowthistle yellow vein virus (SYVV), Sonchus yellow net virus (SYNV) and eggplant mottled dwarf virus (EMDV) virions contained two M proteins and no detectable NS protein. The M and G proteins of LNYV and SV were easily released from the nucleocapsid after incubation with 1% Nonidet P40 (NP40), whereas the G protein and only a proportion of one of the M proteins were released from the nucleocapsids of SYVV, SYNV and EMDV after incubation with 1% NP40. It was necessary to increase the NP40 concentration to 4% to release both M proteins from SYVV nucleocapsids.

Abstract: BK virus (BKV) DNA sequences were not detected in 142 human tumors analyzed by DNA-DNA reassociation kinetics and blot hybridization. The investigation was focused mainly on those rare types of human tumors (ependymomas, choroid plexus papillomas, tumors of pancreatic islets and osteosarcomas) that are induced with highest frequency by BKV in experimental animals. In addition, other tumors of the urinary apparatus and of the central nervous system were analyzed. BKV tumor (T) antigen was not detected in neoplastic tissues, and BKV T antibodies were not found in sera and cerebrospinal fluids from patients with neoplasms. Sequences homologous to BKV DNA were found in normal tissue from a kidney carrying a carcinoma. The neoplastic tissue from the same organ, however, had no sequences homologous to BKV DNA. Such DNA does not belong to BKV but probably to another papovavirus related to BKV.

Abstract: A sensitive solid-phase, enzyme-linked immunosorbent assay (ELISA) was developed for detection of serum IgA antibodies to varicella-zoster virus (VZV). The antigen consisted of a sonically disrupted e

Abstract: Epstein-Barr virus (EBV) from P3HR-1 cells, but not from B95–8 cells, can induce the synthesis of thymidine kinase (TK) in TK-negative Raji cells. The synthesis of TK was slightly reduced, but not inh

Abstract: A reproducible growth curve was established for the propagation of Autographa californica (Speyer) nuclear polyhedrosis virus (ACMNPV) in a continuous insect line from Spodopterafrugiperda (J. E. Smith) during large-volume production. A newly developed method for quantitation of polyhedra inclusion bodies (PIB) by electron microscopy (EM) during the growth cycle was compared to hemocytometer counts. The virus particles (VP) ratio to PFU and VP per PIB were established by EM methods. Optimal yields of PIB and cell-free virus with biological activities were obtained in six consecutive production lots when the growth curve conditions were followed. The DNA of the viruses produced in the 1st and 8th passages in the S.frugiperda cell line was treated with restriction endonucleases and compared with that from the E-2 cloned variant of this virus. Data confirmed that the virus was the ACMNPV and also indicated that there were no detectable changes after 8 passages in insect cell culture.

Abstract: Seven Australian infectious bronchitis viruses incorporated radioactive amino acid label during growth in two types of cell culture. From purified virions, four major polypeptides of molecular weights

Abstract: DNA was prepared directly from preparations of papovavirus excreted in the urine of 2 patients on immunosuppressive therapy, without preliminary amplification in cell cultures. Eco R

Abstract: 98 antisera prepared against 25 simian adenoviruses and 31 adenovirus types from various nonprimate mammals and birds were tested for their ability to neutralize 35 human adenovirus prototypes. Antise

Abstract: Human cytomegalovirus (HCMV) was found to replicate in passaged fibroblastic human first trimester and term placental cells. The time-course of viral DNA replication as well as virus production in these human placental fibroblasts was similar to that in human embryo fibroblast cultures. In contrast, HCMV did not replicate in primary placental epithelioid cells. Continued passage (5 or more) of primary placental epithelioid cells was necessary to convert these cells to a state of permissiveness. The permissive cells were, however, fibroblasts. HCMV DNA replication in passaged placental fibroblastic cells was not affected by treatment with insulin or human chorionicgonadotropin. Furthermore, no replication of HCMV DNA occurred in choriocarcinoma cells, the epithelioid cells derived from cancer of the placenta. These results suggest that epithelial placental trophoblasts, either normal or transformed, were nonpermissive for HCMV. The permissiveness of HCMV infection to secondary placental cells which was observed might be due to the strong selection of fibroblastic cells in vitro.

Abstract: The role of human cytomegalovirus (CMV) was examined according to serological patterns in 37 patients with adenocarcinoma of the colon (ACC). The sera were examined for the presence of IgG antibodies

Abstract: F1 hybrid mice, resulting from a cross between a susceptible and a resistant parent, were infected with a cloned substrain of mouse hepatitis virus type 3 (MHV3). Results showed various evolutive patterns ranging from fulminant hepatitis to persistent infection and excluded virus variation as an explanation for different disease types. Since host resistance to MHV3 has been previously shown to be under the genetic influence of 1 or 2 genes only rather than a polygenic phenomenon, these results strongly suggest that nongenetic factors play a major role in the determination of evolutive patterns.

Abstract: Nuclear involvement of the host cell in Junin virus (JV) replication was studied. α-Amanitin was shown to inhibit JV yield, and RNA synthesis in cell nuclei was found to be augmented during the eclips

Abstract: Molecular hybridization analysis (MHA) was used to show that several tobamoviruses isolated in China (namely Populus bushy top virus, Dihuang degeneration virus, common tobacco mosaic virus, tomato mo