Persistent productive HIV infection in EBV-transformed B lymphocytes

The susceptibility to HIV infection of 14 B-cell lines established from five healthy HIV seronegative and from six HIV seropositive subjects by lymphocyte transformation with EBV and/or by lymphocyte cultivation with cyclosporin A was studied. Although the cell lines contained different proportions of CD4-positive cells, as shown by flow cytometry, all of them could be infected with the SF-2 strain of HIV. Infection was blocked by a monoclonal antibody directed against the viral attachment site of the CD4 molecule, even in a line that lacked demonstrable CD4 receptors. B-cell lines with high proportions of CD4-expressing cells produced HIV p24 antigen more rapidly and at higher concentrations than cell lines with low CD4 expression. Although HIV infection resulted in some cytopathic effects, it was possible to cultivate the infected cells for more than 8 months without refeeding the cultures with uninfected cells. Even in long-term cultures, there was a continuous production of infectious HIV, as detected by transfer of culture supernatants to other susceptible cell lines. The production of viral antigens was consistently more pronounced in the B-cell line with the highest CD4 positivity than it was in a permissive T-cell line (HUT-78) infected in the same manner. These results indicate that HIV can chronically and productively infect transformed B cells via interaction with CD4 molecules. Thus it is possible that B cells may constitute a source of infectious virus in HIV-infected EBV-positive individuals.     

Guidelines to avoid personnel contamination by infective agents in research laboratories that use human tissues

Summary The personnel in laboratories that utilize tissue and fluids from humans and other primates are at risk for infection with agents, including the viruses causing hepatitis, AIDS, and other infective agents such as mycobacteria tuberculosis. To minimize the chance of infection of laboratory personnel, carefully organized policies and procedures to minimize exposure to infective agents must be established in research laboratories. We outline some of the approaches of hospital clinical laboratories which have proved most effective in minimizing transmission of infections from samples to laboratory personnel. Also, we discuss simple considerations important in the use and in the selection of safety equipment. These guidelines and references to other safety information are provided to aid research laboratories in establishing safety procedures that will minimize chances of personnel contamination with infective agents from research samples.     

Effects of Killed and Live Attenuated Influenza Vaccine on Symptoms and Specific Airway Conductance in Asthmatics and Healthy Subjects

Killed and live influenza virus vaccines were given to asthmatics and healthy subjects to investigate symptoms and alterations in their respiratory performance after vaccination. Polyvalent killed influenza virus vaccine was given to 16 asthmatics and live attenuated influenza virus vaccine to 23 asthmatics and 21 healthy subjects. Fourteen of the 16 asthmatics vaccinated with the killed vaccine displayed a significant rise in serum antibody level as measured by a single radial haemolysis in gel (SRH test). 11 of the 23 asthmatics and 14 of the 21 healthy subjects vaccinated with the live attenuated vaccine displayed a significant rise in the SRH test. Among the subjects with no measurable initial antibodies and with a significant rise in the SRH test, one asthmatic vaccinated with the killed vaccine experienced symptoms of common cold with fever and dyspnoea 1 week after vaccination. Three asthmatics and four healthy subjects vaccinated with live attenuated vaccine experienced mild symptoms, mainly rhinorrhoea, cough and sore throat 2 to 3 days after vaccination. No alterations in specific airway conductance in asthmatics or in healthy subjects were observed. We conclude that both killed and live attenuated influenza virus vaccines are tolerated well by asthmatics and appear to be safe for asthma patients.     

Study of herpes simplex virus type 1 populations obtained from recurrences and primary infections

The analysis of 23 clinical isolates of herpes simplex virus type 1 (HSV-1) showed that 15 of 15 isolates that had undergone a few passages in tissue culture (fresh isolates) and two of eight isolates that had never been passaged (new isolates) were composed of a mixed population with respect to plaque morphology in Vero cells. Cloning and characterization of 10 large plaque viruses (L variants) and nine small plaque viruses (S variants), obtained from seven different isolates, showed the following. BamHI DNA restriction patterns of the L and the S variants from a single isolate differed only with respect to the electrophoretic mobility of the fragments that contain reiteration of specific sequences; they did not differ regarding the presence or the absence of restriction endonuclease cleavage sites. The L and S variants differed with respect to the electrophoretic profiles of infected cell glycoproteins, thermosensitivity of growth and plaquing efficiency at 39 degrees C, and, at least in the case of the two couples of variants that we tested, pathogenicity for the mouse. The hypothesis that the L variants might arise from the S variant during in vivo replication is discussed.     

Effect of sex and the phase of the estrous cycle on intensity of injury and repair processes in the liver of rats with acute carbon tetrachloride poisoning

The pattern of injury and repair in the liver of Wistar rats depending on sex, the phase of the estrous cycle, and also under the conditions of deficiency of female sex hormones and after injection of -estradiol into ovariectomized rats was studied by morphometric, histo chemical, and electron-microscopic methods. Structural disturbances caused by CCl₄ were found to be increased and reparative reactions inhibited in the liver of females both during the period of a natural increase in the blood estrogen concentration and under the influence of exogenous estradiol, and ovariectomy also had a protective effect. In males, structural changes in the liver were more marked than in females with a low blood estrogen level and differend only a little from those in females during the period of increased secretion of sex steroids.Central Research Laboratory, Novosibirsk Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 4, pp. 460–464, April, 1978.     

Demonstration of Borna disease virus (BDV) in specific regions of the brain from horses positive for serum antibodies to BDV but negative for BDV RNA in the blood and internal organs

Sero- and molecular-epidemiological studies on Borna disease virus (BDV) infection show that BDV RNA is not always detected in the peripheral blood mononuclear cells (PBMCs) from serum anti-BDV antibody-positive individuals such as horses, sheep, cattle, cats, and humans. In this study we demonstrated BDV RNA signals by polymerase chain reaction only in restricted regions of the brain from horses with locomotor disease. Four of six horses examined showed apparently positive reactions for anti-BDV antibodies. Specific regions of the brain of these four horses were positive for BDV RNA but the internal organs, lymph nodes, and PBMCs were negative. Histological studies of their brains revealed no apparent histological abnormalities such as inflammatory reactions. These results suggest that BDV chronically infects certain restricted regions of brain in seropositive horses. Received: 6 January 1997     

IL-12 inhibits in vitro immunoglobulin production by human lupus peripheral blood mononuclear cells (PBMC)

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by polyclonal B cell activation and by the production of anti-double-stranded (ds) DNA antibodies. Given the inhibitory effects of IL-12 on humoral immune responses, we investigated whether IL-12 displayed such an activity on in vitro immunoglobulin production by SLE PBMC. Spontaneous IgG, IgG1, IgG2, IgG3 and IgM antibody production was dramatically reduced by addition of IL-12. These results were confirmed by Elispot assays detecting IgG- and anti-dsDNA-secreting cells. While IL-6 and TNF titres measured in PBMC supernatants were not modified by addition of IL-12, interferon-gamma (IFN-γ) titres were up-regulated and IL-10 production down-regulated. Since addition of IFN-γ did not down-regulate immunoglobulin production and since the inhibitory activity of IL-12 on immunoglobulin synthesis was not suppressed by anti-IFN-γ antibody, we concluded that the effect of IL-12 on immunoglobulin production was not mediated through IFN-γ. Our data also argue against the possibility that down-regulation of endogenous IL-10 production was responsible for the effect of IL-12. Thus, inhibition of IL-10 production by IFN-γ was not accompanied by inhibition of immunoglobulin production, and conversely, restoration of IL-10 production by anti-IFN-γ antibody did not suppress the inhibitory activity exerted by IL-12 on immunoglobulin production. Taken together, our data indicate that reduction of excessive immunoglobulin and anti-dsDNA antibody production by lupus PBMC can be achieved in vitro by IL-12, independently of IFN-γ and IL-10 modulation.     

利用双扩增聚合酶链反应检测非甲非乙型肝炎患者血清中丙型肝炎病毒RNA

利用丙型肝炎病毒（ＨＣＶ）５’－端序列合成两对引物，建立了灵敏、特异的ＨＣＶＲＮＡ双扩增聚合酶链反应检测方法。用此方法及第二代Ａｂｂｏｔｔ酶联抗－ＨＣＶ检测试剂盒，检测了４４例非甲非乙型肝炎患者血清及１０名抗－ＨＣＶ阴性健康人。在４４例患者中，４１例（９３％）ＨＣＶＲＮＡ阳性，３６例（８２％）抗－ＨＣＶ阳性，３３例（７５％）ＨＣＶＲＮＡ、抗－ＨＣＶ全部阳性。３例ＨＣＶＲＮＡ阴性，但抗－ＨＣＶ阳性，另外，有８例抗－ＨＣＶ阴性，ＨＣＶＲＮＡ阳性。１０名健康人ＨＣＶＲＮＡ均为阴性。结果表明，大部分（９２％）抗－ＨＣＶ阳性患者带有ＨＣＶ，但为了检测所有病毒血症患者，抗－ＨＣＶ检测是不够的，利用双扩增ＰＣＲ方法检测ＨＣＶＲＮＡ对于抗－ＨＣＶ阴性患者的诊断是非常有用的。     

Antigenic variation in alkaline deoxyribonuclease induced by three different strains of Epstein-Barr virus

To determine whether biological and/or biochemical variants exist between strains of Epstein-Barr virus (EBV), we superinfected Raji cells with the nontransforming lytic strain of EBV (HR-1), and two isolates that both transform B-lymphocytes and superinfect Raji cells, B95–8, and NPC-EBV. The superinfected cells were assayed for EBV specific DNase. A new electrophoretic form of DNase was observed in cells superinfected with B95-8 EBV as compared to the enzymes induced by the HR-1 and NPC-EBV isolates. There were antigenic differences in the DNase induced by the EBV strains. Since antibody to EBV DNase is a marker for nasopharyngeal carcinoma (NPC), these data may have implications for EBV-associated disease.