- Volume 64, Issue 2, 1983

A cloned culture of secondary anti-herpes simplex virus (anti-HSV) cytotoxic T lymphocytes (CTL) generated in vitro when adoptively transferred to intact or cyclophosphamide (CP) pretreated syngeneic mice protected the recipients from death following intraperitoneal infection with HSV-1. This in vivo protective effect conferred by anti-HSV CTL was virus-specific and H-2K/D-restricted. Twenty-four h after HSV-1 infection of BALB/c mice (intact or CP-pretreated) relatively high levels of serum interferon-γ were observed in the recipients of syngeneic anti-HSV CTL and this event may explain, at least in part, the CTL-mediated protective effect.

Polyvalent serum directed against C3 receptors was employed in an attempt to block Epstein—Barr virus (EBV) binding to virus receptor-containing cell lines. The serum eliminated 90% of virus binding to Daudi and BJAB, lines which express only the C3d receptor. Raji and Ramos cells, which express the C3d, C3b and C3bi receptors, still adsorbed 70% of their virus capacity in the presence of excess antiserum. These effects were independent of the virus strain. In the light of previous reports, these data imply that, although the two receptors, EBV and C3d, are closely associated, the binding sites of EBV and complement are distinct. Additionally, an unusual EBV substrain-specific receptor found on U698 and P3HR-1/ASNP lines was shown to be independent of complement receptors.

Preparative SDS-polyacrylamide gel electrophoresis has been used in the purification of the gp340 component of Epstein-Barr (EB) virus-determined membrane antigen (MA), in tractable quantities, from the B95-8 marmoset lymphoblastoid cell line. Successful renaturation of the purified molecule was achieved. This procedure gave a 50-fold increase in the recovery of antigen compared to conventional techniques. The data suggest that the antigenic sites recognized by human sera containing antibodies to MA are largely confined to the protein portion of the molecule. An eightfold improvement in the yield of gp340 was obtained when B95-8 cells were cultured in the presence of 12-O-tetradecanoyl-phorbol-13-acetate. Gel filtration studies indicate that the major polypeptide components of MA are not associated in detergent solution. Immunization of rabbits with purified and renatured gp340 resulted in the generation of high-titre antisera which were specific for gp340, demonstrating that antigen prepared by this procedure is suitable for further evaluation as an experimental vaccine against EB virus infection.

Mouse cytomegalovirus (MCMV) grew to higher titres in spleen, liver, kidney and salivary gland of mice, and caused more sickness and death in susceptible (CD1) mice following treatment with anti-interferon globulin (AIG). In the resistant (C3H) strain of mice, organ titres were higher following AIG treatment but there was no sickness or mortality. Spleen necrosis was more severe in AIG-treated mice, indicating that this necrosis was not caused by interferon-mediated activation of natural killer (NK) cells. CD1 mice developed a high level of NK activity during MCMV infection and this was greatly reduced by AIG treatment. AIG was equally effective in increasing virus titres in NK-deficient beige (bg/bg) C57 B1.6 mice which showed a low level of NK activity even after MCMV infection, suggesting that interferon protects against MCMV by its direct antiviral effect on cells rather than by activating NK cells.

Six avian paramyxoviruses isolated from wild and domestic ducks in the United States, Hong Kong and Japan were characterized antigenically and genetically. All viruses examined were shown to be antigenically closely related. Oligonucleotide patterns of duck/Miss/334 and duck/Miss/406 were apparently distinguishable from those of duck/Miss/116 and duck/Miss/320 isolated in the same area of the United States. On the other hand, two viruses isolated from a domestic duck in Hong Kong (duck/Hong Kong/D3/75) and from a domestic duck in Japan (duck/Tokyo/41/78) were genetically very similar to that of duck/Miss/116, suggesting that these three viruses represent a genetically homogeneous group and may be of the same origin.

Under optimal conditions, of high multiplicities of infection and with trypsin included in the medium throughout the incubation period, high yields of infectious influenza A and B viruses (106.5 p.f.u./ml) and of antigenically active haemagglutinin (HA) (1 µg/HA/106 cells) were produced in human diploid MRC-5 cells. Budding virus particles were seen as spherical or short rod-like protrusions on the surface of the infected cells, and also on cell filopodia. Virus-induced cytoplasmic and nuclear inclusions were present in infected cells. This virus-human cell system may be suitable for studies of influenza virus persistence and for production of immunologically active HA antigen.

Two systems utilizing extracts derived from nuclei of adenovirus-infected cells which synthesize adenovirus DNA in vitro were analysed for indications of ADP-ribosylation of virus proteins. On incubation with [32P]NAD or [14C]NAD, modification of the adenovirus T antigen could be demonstrated in one of these systems. ADP-ribosylation of adenovirus core proteins V and VII could also be demonstrated with both nuclear extracts. However, using 3-aminobenzamide, a specific inhibitor of poly (ADP-ribose) polymerase, there was no evidence either in vivo or in vitro that ADP-ribosylation played a critical role in the replication process.

Mouse fibroblast LM cells growing continuously in the absence of serum and exogenous lipids are proposed as a model for studying interferon action. Several of its activities, namely the inhibition of virus and cell growth, and the increased cytotoxicity of poly(rI).poly(rC), are shown to be potentiated in such conditions. Since cells cultured under these conditions are devoid of precursors of prostaglandin biosynthesis, the data suggest that none of the three effects of interferon depends on active prostaglandin synthesis.

Radioactive choline was incorporated by HeLa cells into a characteristic distribution of choline-associated lipid macromolecules when cytoplasmic extracts are centrifuged in discontinuous sucrose gradients. The proportional distributions of radioactivity among three peaks in the gradients were altered by infecting the HeLa cells with rhinovirus type 2 and 14, or with poliovirus. Poliovirus infection induced similar distributions of radioactivity in both LLCMK2 and HeLa cells with the greatest radioactivity increase in peaks nearest the tops of the gradients. When the LLCMK2 cells were infected with echovirus 12, the major increase in choline-associated radioactivity was in a peak near the middle of the gradients, in a pattern of distribution that was more similar to that of rhinovirus-infected HeLa cells than to poliovirus-infected LLCMK2 cells. Radioactive glucosamine-labelled, cytoplasmic macromolecules were distributed differently from those labelled with choline in both infected and uninfected cultures, and infection by all four virus strains sharply decreased glucosamine-associated radioactivity in the gradients, suggesting that the synthesis of glucosamine- and choline-containing structures are under different cytoplasmic controls. When these results are taken together with the findings of clearly different patterns of distribution of choline-associated radioactivity in gradients prepared from uninfected HeLa and LLCMK2 cells labelled at 37 °C, and the closer similarity between them when labelled at 34 °C, it appears that choline-containing lipids can have specific temperature-regulated processes in different cell types, and that different viruses may have common and selectively specific modifying effects on the synthesis of cytoplasmic lipid macromolecules.

Small- and large-plaque-producing viruses were selected from the enterovirus 71 (E71) prototype, BrCr. The small-plaque virus was a temperature-resistant (tr) strain which could multiply at 39.5 °C as well as 35 °C. The large-plaque virus was temperature-sensitive (ts) and could not grow at 39.5 °C. It was shown that the ts strain was much less neurovirulent for monkeys than the tr strain. Both tr and ts strains reacted with homologous and heterologous antibodies in cross-neutralization tests. While no difference was found between tr and ts strains in the size of virion polypeptides, the VP1 polypeptide could be differentiated by isoelectric focusing. Genomic differences between the two strains were found by oligonucleotide mapping.

The virion RNAs of six independent isolates of Drosophila C virus (DCV) have been characterized by ribonuclease T1 oligonucleotide fingerprinting. All six isolates share common large oligonucleotides. Two of the isolates, from Vigier and Charolles, are closely related while a third French isolate from Gif is more distantly related. The other three isolates, two from Morocco (Taroudant and Ouarzazate) and one from the French Antilles were mixtures of more than one variant of DCV, but were clearly related to the three French isolates.