Sendai virus multiplication in the presence of ceruloplasmin and homologous virus envelopes.

Preincubation of Sendai virus with ceruloplasmin induced in chorioallantoic membrane (CAM) fragments the synthesis of a population with decreased infectivity and high haemagglutinating (HA) and neuraminidase (NA) activities, whereas preincubation with solubilized virus envelopes led to the production of a viral population with the same infectivity as the control, but with lower HA and NA activities. Preincubation of the virus with a mixture of ceruloplasmin and solubilized envelopes depressed the overall virus synthesis; the resulting population had a low infectivity and high HA and NA activities. The variation in the HA/NA ratio indicates a modification in the envelope structure.

The presence of interferon and type A immunoglobulins in the nasopharyngeal secretions of volunteers immunized with an inactivated influenza vaccine.

The presence of interferon and type A immunoglobulins (IgA) was followed up in the nasopharyngeal washings collected from volunteers immunized intranasally with an inactivated influenza vaccine [strain A/Rom 1/73 (H3N2)]. Interferon was detected 24 hours after vaccine administration, its incidence being similar to that in the course of acute infection. Intranasal administration of inactivated influenza vaccine stimulated the production of secretory IgA in 3 of 10 samples collected 12 days after vaccination. At the same time, IgA were found in 4 samples collected before vaccination, and inhibited in certain cases the stimulation of interferon synthesis. The practical importance of the route of influenza vaccine administration is discussed.

Some physico-chemical and biological properties of egg-Sendai virus with altered haemagglutinin-neuraminidase protein.

Some physico-chemical and biological properties of egg-cultivated Sendai (egg-Sendai) virus particles with altered haemagglutinin-neuraminidase (HN) protein were studied. These particles were obtained accidentally from purified egg-Sendai virus stored at +4 degrees C. Egg-Sendai with altered HN protein was not infectious for cultured cells, but could still infect embryonated eggs. Though egg-Sendai virus with altered HN protein and glycoproteins had no haemagglutination activity, it unexpectedly possessed a relatively high neuraminidase (NA) activity representing about 70% of the activity of normal particles. Since polyacrylamide gel and rocket immunoelectrophoresis indicated that the altered particles contained only F protein, possibly the native HN was converted into a molecule of the same molecular mass as F protein.

Effect of some anthracycline antibiotics on the neuraminidase activity of Sendai virus and its isolated glycoproteins.

Anthracycline antibiotics violamycin BI (VBI) and adriamycin (Adr) strongly inhibited the neuraminidase (NA) activity of Sendai virus and of its isolated glycoproteins, occurring either in solution or associated in liposome-like particles. NA did not exhibit the classical Michaelis-Menten kinetics: the plot of reaction velocity versus substrate concentration was sigmoidal, while Hill's plotting indicated that the enzyme has at least two binding sites for the substrate. The reaction kinetics obtained suggested that Sendai virus NA acts as an allosteric enzyme, when its material support, the HN is located on the virus surface. The inhibitory effect of the anthracycline antibiotics in question on the NA activity seemed to be similar to that of negative effectors.

Peculiarities of the virus-host cell relationship in a calf kidney cell line persistently infected with measles virus.

Persistent infection with measles virus established in a calf kidney cell line differed in some features from other measles virus carrier systems. After a variable life span, ranging from 50 to 1100 days, six of the chronically infected cell lines showed an evolution towards lytic infection. Only one of these lines, the K-2 cell line, exhibited marked morphological, growth and chromosomal alterations suggesting in vitro cellular transformation. The transformed K-2 cells released infectious measles virus with several modified biological parameters. Persistent infection was not due to the accumulation of thermosensitive mutants or defective particles. The role of the host-cell factor and of the selection of the virus population during its passage in RV cells are discussed.

Interaction of influenza and parainfluenza viruses with polycations, organic oligocations and chromosome preparations.

As evaluated by light scattering at 90 degrees, natural organic oligocations such as putrescine, spermidine and spermine interfered with myxovirus aggregates which were induced by the histone H2A and strongly amplified by shaking during incubation. In contrast, the synthetic oligocation 1.7-diamino heptane itself aggregated the virus particles, its action being unmodified by adding polycationic H2A in abundance. When human chromosome preparations treated with protamine solution and shaked during incubation were covered with a stable polycationic molecular layer, the chromosomes had become unstainable by the Giemsa method even if the dye was used in excess. Nevertheless, the affinity of influenza virus particles for protamine was so high that they were able to dissociate the protamine molecules from the preformed complexes reconstituting the affinity of chromosome preparations to Giemsa stain. The virus-caused shift in the staining ability of chromosomes did not occur when bacterial suspension was added instead of the viral one. The model of oligocationic relaxation and of polycation condensation accounting for the modulatory effects of polyamines is discussed.

[Importance of the virology laboratory in the diagnosis of virus diseases]. / Importanta laboratorului de virusologie în diagnosticul rapid al virozelor

Introduction. Principles of the Modern Diagnosis in Virology--isolation of the causative agent;--histologic and electronoptical diagnosis;--serologic. Efficiency of the viral diagnosis. Modern and Rapid Diagnostic Methods--progress in the technology of cell cultures and immunofluorescence;--new serologic methods.

[The AIDS epidemic among children in Romania. The current data and short-term forecasts]. / L'épidémie de SIDA chez les enfants en Roumanie. Données actuelles et prévisions à court terme.

Situation and main characteristics of the AIDS epidemics in Romania are analysed. Prevention measures, among which it is worth mentioning a correct information of the population, are proposed.

[Different modalities for registering AIDS cases. Their importance for the European epidemic]. / Considérations sur les différentes modalités d'enregistrement des cas de SIDA. Signification pour l'épidémie européenne.

The high number of AIDS cases diagnosed in different European countries imposed to reconsider the opinion that European epidemic is just reflecting the American epidemic. The whole morbidity des not point out the peculiar elements of HIV infection propagation in Europe. The exponential rise of reported case number during 1987 imposes to analyse the new epidemiological situation.

The genetics of viral infection pathology.

The genetic diversity of viruses and the genetic constitution (polygenic configuration) of susceptible organisms participate together in the determination of a virus disease and of its clinical forms. Genes of sensitivity to viral infection, genes of nonspecific defense (encoding for interferons, complement factors), immune response regulating genes and immunoglobulin genes would form the background of an intrinsic polygenic group involved in viral infection pathology.

Presence of anti-albumin antibodies in viral hepatitis, infectious mononucleosis and several forms of cancer.

Anti-albumin antibodies previously described by different authors in viral hepatitis were also investigated in patients with other diseases. Significant titers of such antibodies could be detected -- by passive hemagglutination reactions using a system of bovine serum albumin-coated sheep red blood cells and human sera -- not only in viral hepatitis, but also in infectious mononucleosis cases and in patients with different forms of cancer. Onto-phylogenetic considerations on the significance of these antibodies for different stages of the process of cell de-differentiation or for disorders of intercellular contacts under the action of some viral agents are discussed.

Antimeasles vaccination by natural routes--experimental background and practical consequences.

A limited number of passages (up to 10) in human diploid cells (HDC) does not lead to changes in the phenotypic markers indicating the degree of attenuation of the vaccine strains of measles virus (Schwarz, Leningrad-16, Edmonston-Zagreb). At the same time, the increase in virus titer and the acquiring of immunogenicity when administered by nonparenteral (conjunctival, nasal) routes represent the prerequisites of a convenient form of application of the measles vaccine prepared in HDC.

Investigation of humoral and cell-mediated immunity aspects in mice with experimental latent herpes infection.

An experimental latent herpes infection was established by intradermal inoculation of the mouse ear or of the footpad with a wild strain and a temperature-sensitive (ts) mutant of herpes virus type 2. The wild strain was latency-positive irrespective of the inoculation site; the ts mutant induced latent ganglionic infection only when inoculated in the footpad. Neutralizing antibodies could be detected only after inoculation of the wild strain. The establishment of latency was not prevented by the presence of either a humoral or a cell-mediated immune response.

Trends in the rapid diagnosis of viral infections.

The authors discuss different aspects of the rapid diagnosis of viral infections: its necessity, its characteristics, the recent advances having allowed the development of modern techniques. Further, the main categories of procedures used in rapid viral diagnosis are reviewed: 1) electron microscopy, 2) immunofluorescence and immunoperoxidase techniques; 3) solid-phase systems with labelled reactants; 4) agglutination with supporting particles; 5) counterimmunoelectrophoresis; 6) rapid/early serological diagnosis. Data are discussed as regards the possibility of the large-scale application of rapid viral diagnosis procedures in Romania.

Study of cell surface antigens induced by herpes simplex virus. Note I. Identification of the antigens by means of protein A-containing staphylococci.

A rapid, easy-to-perform and specific technique for the visualization of herpes simplex virus (HSV)-induced cell surface antigens is described. The technique consists in the incubation of HSV-infected cells with hyperimmune HSV antiserum and formation of rosettes with FITC-labelled Cowan strain staphylococci containing protein A. The "nonspecific background" of the reaction can be estimated by comparison with the rate of bacteria binding by control cells not incubated with HSV antiserum.

Persistent measles virus infection in a calf kidney cell line. Note II. Study of some biological markers of the measles virus isolated from a selected chronically infected cell line.

The biological characteristics of a measles virus strain (Co-69/pi) isolated from a selected chronically infected calf kidney cell line (K-2) are studied in comparison with those of thw wild parental CO-69 and of the attenuated Schwarz measles virus strain. Co-69/pi is a variant of the parental Co-69 virus and has characteristics of an attenuated strain. Some of the characteristics acquired by the Co-69/pi strain (cytopathogenicity, size of plaques) proved to be stable in the course of passages on a simian substrate. The mechanism having led to the appearance of this variant in the chronically infected cell line are discussed.

Results obtained with the NIVGRIP inactivated influenza vaccine applicable by nasal and/or oral route.

The NIVGRIP inactivated influenza vaccine prepared in the "Stefan S. Nicolau" Institute of Virology has proved its efficacy in the specific prophylaxis of influenza. The vaccine can be administered by nasal and/or oral route and has a very low reactogenicity. Application of the NIVGRIP vaccine results in seroconversion rates of 50-70% and in rises in the levels of local neutralizing antibodies in 75-80% of the vaccines. Numerous epidemiological surveys have ascertained that the protection rate obtained by nasal administration of the NIVGRIP vaccine ranges from 50 to 90%, being comparable with that of other commercially available vaccines. The advantages of the use of an inactivated, whole virus vaccine applicable by nonparenteral routes are discussed.

[Gamma interferon induced in human leukocytes by phytohemagglutinin: its production and biological characteristics]. / Inteféron gamma induit dans des leucocytes humains par la phytohémagglutinine: production et carcatéristiques biologiques.

Human gamma type interferon (IFN) preparations were obtained through phytohemagglutinin stimulation of leukocytes from the peripheral blood. Biological value of these preparations varied between 160 u and 800 u/ml, depending on leukocyte incubation medium, culture system and inductor conservation. The rising of the antiviral activity through association between gamma (3 u) and alpha (27 u) interferons was revealed by the virus quantity reduction (in this case the vesicular stomatitis virus was used) during a 24-hour multiplication cycle. The protection ensured by the mixture of the two types of interferon was about ten times higher than the additive effect of the two preparations. Study of the antiproliferative activity of a gamma interferon preparation was conducted on two human cell lines of tumoral origin (T-10 from a glioblastoma, and HEp-2) and revealed the difficulties to quantify precisely this property of the crude gamma interferon preparations.