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Biomedical subjects

B Meignier

Publications and source records attributed to B Meignier.

At least 37 records · Page 2Linked to original sources
PubMed1992

Immunisation with canarypox virus expressing rabies glycoprotein.

Poxviruses have many useful features as vectors for genes that carry immunising antigens from other viruses, such as ease of production and induction of cellular and humoral immunity, but there is concern about the safety of vaccinia virus. We turned to an avian poxvirus (canarypox); this virus undergoes abortive replication in mammalian cells that enables presentation of early gene products to the immune system. Canarypox virus was used as a vector for the rabies glycoprotein G gene. The safety and efficacy of the recombinant (ALVAC-RG; vCP65) were tested in several animal species, then it was subjected to a phase 1 clinical trial. Twenty-five volunteers were randomly assigned to subcutaneous injections of the recombinant (three groups [A, B, and C] received two doses each of 10(3.5), 10(4.5), and 10(5.5) tissue-culture infectious doses50, respectively) or of human diploid cell culture vaccine (HDC; 6.52 international potency units per dose). 28 days after the second dose, all nine ALVAC-RG group-C subjects and two of three group-B subjects had rabies neutralising antibody concentrations of at least 0.5 IU/ml, the level associated with protection in animals. Although the geometric mean titre of these antibodies at that time was lower in group C than in the ten HDC recipients (4.4 [range 0.9-12.5] vs 11.5 [4.7-25.3] IU/ml), a single booster dose at 6 months induced a recall response in volunteers primed with either vaccine. Side-effects associated with ALVAC-RG were mild and of short duration and occurred at similar frequency to those of HDC vaccine. This study has shown the potential of non-replicating poxviruses as vectors for vaccination in human beings. Trials of canarypox-virus recombinants at higher doses and by other routes of administration are needed.

Adult↗
PubMed1992

NYVAC: a highly attenuated strain of vaccinia virus.

A highly attenuated vaccinia virus strain, NYVAC (vP866), was derived from a plaque-cloned isolate of the Copenhagen vaccine strain by the precise deletion of 18 open reading frames (ORFs) from the viral genome. Among the ORFs deleted from NYVAC (vP866) are two genes involved in nucleotide metabolism, the thymidine kinase (ORF J2R) and the large subunit of the ribonucleotide reductase (ORF I4L); the gene encoding the viral hemagglutinin (ORF A56R); the remnant (ORF A26L) of a highly expressed gene responsible for the formation of A-type inclusion bodies; the disrupted gene (ORFs B13R/B14R) normally encoding a serine protease inhibitor; and a block of 12 ORFs bounded by two known viral host range regulatory functions (ORFs C7L through K1L). Within this block a secretory protein (ORF N1L) implicated in viral virulence and a functional complement 4b binding protein (ORF C3L) are encoded. The ORFs were deleted in a manner which prevents the synthesis of undesirable novel gene products. The attenuation characteristics of the derived NYVAC strain were compared in in vitro and in vivo studies with those of the Western Reserve (WR) laboratory strain, the New York City Board of Health vaccine strain (Wyeth), the parental plaque-cloned isolate (VC-2) of the Copenhagen vaccine strain used to derive NYVAC, and the avipox virus canarypox (ALVAC), which is naturally restricted for replication to avian species. The NYVAC strain was demonstrated to be highly attenuated by the following criteria: (a) no detectable induration or ulceration at the site of inoculation on rabbit skin; (b) rapid clearance of infectious virus from the intradermal site of inoculation on rabbit skin; (c) absence of testicular inflammation in nude mice; (d) greatly reduced virulence as demonstrated by the results of intracranial challenge of both 3-week-old or newborn mice; (e) greatly reduced pathogenicity and failure to disseminate in immunodeficient (nude or cyclophosphamide treated) mice; and (f) dramatically reduced ability to replicate on a variety of human tissue culture cells. Despite these highly attenuated characteristics, the NYVAC strain, as a vector, retains the ability to induce strong immune responses to extrinsic antigens.

Animals↗
PubMed1992

Comparison of the ability of formalin-inactivated respiratory syncytial virus, immunopurified F, G and N proteins and cell lysate to enhance pulmonary changes in Balb/c mice.

Formalin-inactivated respiratory syncytial virus (FI-RSV), a lysate of HEp-2 cells and proteins F, G and N, immunopurified from infected cell cultures, were compared for their ability to prevent infection and to enhance changes in lung cytology associated with RSV challenge. Mice were immunized at three weekly intervals with serial dilutions of the preparations and challenged by the nasal route 1 week after the last injection; their lungs were analysed 4 days later. The concentration of the immunogens was adjusted to test at least a range of 2 to 500 ng of proteins per injection. The dose of FI-RSV used for immunization influenced both the protection against infection and the potentiation of lung histopathology. There was a strong correlation between the lesion scores and the proportion of larger cells recovered in bronchoalveolar lavage fluid. We therefore used cytological changes as an index of lung alterations in further experiments. Glycoproteins F and G but not protein N were protective against challenge infection. Potentiation was observed in mice immunized with minute amounts (2 ng per injection) of F, G or N. HEp-2 cell lysate also caused potentiation but this required greater than 125 ng of proteins per injection.

Animals↗
PubMed1990

Comparison of lung histopathology and bronchoalveolar lavage cytology in mice and cotton rats infected with respiratory syncytial virus.

Lung histology as well as cell number and size distribution in bronchoalveolar lavage (BAL) were compared in Balb/c mice and in cotton rats, of various immune status regarding the respiratory syncytial virus (RSV), when subjected to challenge with RSV. In mock-immunized animals, RSV infection typically caused microscopic inflammatory lesions of the lungs and the presence of inflammatory cells in the BAL. Immunization with a formalin inactivated vaccine prior to challenge increased the severity of the lung lesions and the number of cells recovered in the BAL. We observed that cotton rats are more convenient to study primary RSV infections, inasmuch naive subjects show more pronounced lesions than do naive mice. Conversely, the changes in lung histopathology and in BAL cytology associated with exposure to formalin inactivated vaccine prior to challenge were more apparent in mice, making them a more suitable model for potentiation studies. Moreover, mice showed less individual fluctuations than cotton rats. The reading of the lung sections could be made less tedious by use of computer image analysis, which results paralleled those of conventional examination. In mice, cytological analysis of the BAL could be used in place of lung histology for some potentiation studies since the number of cells recovered in BAL reflected the intensity of the lung lesions and size distribution profiles typical of potentiation were recognized.

Animals↗
PubMed1990

Isolated gA/gB glycoprotein complex of human cytomegalovirus envelope induces humoral and cellular immune-responses in human volunteers.

Three human cytomegalovirus (HCMV) seronegative individuals were immunized with a single dose of HCMV envelope; two individuals developed neutralizing antibodies. Two naturally HCMV seropositive and three HCMV seronegative human volunteers were immunized with a major glycoprotein complex, gA/gB, of HCMV that had been purified by immunoadsorbent column chromatography. After a single injection of the gA/gB preparation, the naturally seropositive individuals developed higher titres of neutralizing antibodies and temporarily higher HCMV-specific lymphocyte proliferation (HCMV-LP) responses in vitro. The seronegative individuals developed neutralizing antibodies after the third injection of gA/gB, which were present only transiently, but showed a rapid reappearance and increase in titre after the fourth injection. At 1 year after the first injection, the neutralizing antibody titres were still comparable with those of the naturally seropositive individuals. HCMV-LP responses to HCMV in the initially seronegative individuals developed after the second or third injection with the gA/gB preparation and remained positive during the 1-year observation period. These results show that the gA/gB protein induces both humoral and cellular immune responses in humans, and might serve as the basis of a subunit vaccine.

Animals↗
PubMed1990

In vivo behavior of genetically engineered herpes simplex viruses R7017 and R7020. II. Studies in immunocompetent and immunosuppressed owl monkeys (Aotus trivirgatus).

The genetically engineered herpes simplex virus strains R7017 and R7020 were tested in owl monkeys (Aotus trivirgatus) previously shown to model herpetic diseases of immunocompromised patients and neonates. In contrast to the lethal disease seen in monkeys receiving 100-1,000 plaque-forming units (pfu) of wild-type virus, inoculation of greater than or equal to 10(6) pfu of recombinant viruses produced local lesions and viral shedding but not disseminated disease. Latent recombinant viruses were recovered from some ganglia innervating the sites of inoculation. Monkeys protected from lethal infection with wild-type virus exhibit recurrent lesions that increase in frequency and severity after total lymphoid gamma irradiation (TLI). In contrast, monkeys immunosuppressed by TLI and inoculated with R7020 could not be differentiated from irradiated controls with respect to morbidity or mortality. Moreover, the virus was not transmitted from immunosuppressed infected females to normal male cage mates.

Animals↗
PubMed1988

Virulence of and establishment of latency by genetically engineered deletion mutants of herpes simplex virus 1.

We report the results of studies on the biologic properties of seven deletion mutants of herpes simplex virus 1 (HSV-1). The genes deleted from six of these mutants map in the S component of HSV-1 DNA and include those specifying the alpha protein 47, the glycoproteins G and E, the viral protein kinase, and two proteins whose functions are not yet known (open reading frames US2 and US11). The seventh virus [HSV-1(F) delta 305] contained a 700-bp deletion in the thymidine kinase gene. The results of intracerebral inoculation of Balb/c mice indicated that all but one of the deletion mutants in the S component were significantly attenuated. The PFU/LD50 ratios for these mutants ranged from 10(4)- to 10(5)-fold higher than that of the wild-type, HSV-1(F). The PFU/LD50 for mutant R7032, from which the glycoprotein E gene had been deleted, was less than 100-fold higher than that of the parent virus. All of the mutants, with one exception, were able to establish latency in mice; the exception, HSV-1(F) delta 305, was able to establish latency in rabbits.

Animals↗
PubMed1988

In vivo behavior of genetically engineered herpes simplex viruses R7017 and R7020: construction and evaluation in rodents.

The herpes simplex virus (HSV) recombinant R7017 was constructed from HSV-1 (strain F) by deleting a portion of the thymidine kinase (tk) gene and by replacing the sequences representing the internal inverted repeats and adjacent genes in the L component with a fragment of the HSV-2 genome encoding the glycoproteins G, D, I, and a portion of E. In addition, the R7020 recombinant contains an HSV-1 DNA fragment encoding the tk gene fused to the alpha 4 gene promoter. The results of studies in mice, guinea pigs, and rabbits were as follows: Both recombinants remained unchanged after nine serial, intracerebral passages in mice; the recombinants could not be differentiated with respect to attenuation in mice injected intracerebrally, in vaginally infected guinea pigs, and in rabbits inoculated on the scarified cornea. Given intradermally or intramuscularly, the recombinants prevented severe infections by virulent challenge viruses, and R7020 established latent infections (at a low frequency) in all species tested, whereas latent R7017 virus was detected in rabbits only.

Animals↗
PubMed1987

Immunization of experimental animals with reconstituted glycoprotein mixtures of herpes simplex virus 1 and 2: protection against challenge with virulent virus.

Artificial mixtures of the glycoproteins B, C, D, and E of herpes simplex virus 1 and 2 (HSV-1 and HSV-2), purified individually from infected Vero cell lysates by immunoaffinity to monoclonal antibodies, were bound to an aluminum hydroxide gel and were used to immunize mice, guinea pigs, and owl monkeys (Aotus trivirgatus) once or twice (mice and guinea pigs) to as many as four times (owl monkeys). In all animals tested, low levels of neutralizing antibodies were detected only after two or more immunizations. Lymphocyte transformation tests in owl monkeys suggested low or borderline levels of cellular immunity. The survival of immunized mice after intracerebral challenge was inversely related to the challenge dose. Immunized guinea pigs challenged by intravaginal inoculation showed reduced morbidity at the site of inoculation and were protected from CNS disease. Both immunized and nonimmunized monkeys were highly susceptible and could not be differentiated with respect to morbidity or mortality when challenged with 1,000 pfu of HSV-2 by the intravaginal route.

Animals↗
PubMed1986

Failure to induce cervical cancer in mice by long-term frequent vaginal exposure to live or inactivated herpes simplex viruses.

C57 mice aged 8-10 weeks in groups of 50 each received vaginal cotton pellets soaked in lysates of HEp-2 cells, either mock-infected or infected with herpes simplex virus I, herpes simplex virus 2, and highly attenuated recombinant viruses 5 times a week for 89 to 114 weeks. An untreated group was also included. The mock-infected and some of the infected cell lysates were exposed to ultraviolet light at a dose sufficient to inactivate virus. Smears of exfoliated vaginal cells collected once a month and histopathologic sections of genital organs removed at autopsy were coded and examined blind for the presence of abnormal cells indicative of malignant changes and cervical cancer, respectively. Sera collected before termination of the study were tested blind for the presence of antibody to infected cell lysates and to purified herpes simplex virus glycoprotein B. The results were as follows: Over 74% of 826 mice examined at autopsy contained tumors at non-genital sites. The tumors were randomly distributed among the various groups. Gross genital abnormalities were less common in untreated animals than in mice receiving vaginal implants. The fraction of mice which developed cervical cancer diagnosed by histopathologic examination was small (7.2%) and not significantly different among various groups. There was no correlation between the presence of abnormal exfoliated cells indicative of early invasive or invasive cancer lesions and the histopathologically proven diagnosis of micro-invasive or invasive cervical cancer. The incidence and levels of antibody were highest in animals exposed to live virus; some mice exposed to inactivated virus also developed weak or moderately high antibody levels. The presence of antibodies did not correlate with the presence of histopathologically proven cervical cancer. The results do not support the ability of herpes simplex viruses to cause genital neoplasia in mice.

Animals↗
PubMed1986

Analyses of transplanted murine tumors for HSV DNA sequences.

Meignier et al. (1986) report the results of exposure of C57BL/6NCr mice to vaginal plugs containing live or inactivated herpes simplex virus 1 or 2 (HSV-1 or HSV-2) or recombinant viruses 5 times a week for up to 114 weeks. Genital organs showing abnormalities were transplanted into nude mice. Of 33 transplants, 13 produced subcutaneous tumors in nude mice and 12 were subsequently transplanted into C57BL/6NCr mice. We report that the DNA extracted from coded tumor tissues of nude mice and from normal viscera of the same rodents did not hybridize with HSV-1 and HSV-2 DNA probes representing the viral genomic regions shown previously to be capable of morphologically transforming cells in culture. The sensitivity of the assays was such that we could detect 0.5 copies of the HSV sequences of complexity equal to or greater than 1 Kbp per cell DNA equivalent. To control for the sensitivity of the assays in the actual hybridizations, the tumor-cell DNA was also hybridized with a beta-globin mouse DNA probe. A striking feature of these control hybridizations was the detection of beta-globin polymorphism in some nude mouse tumors. The beta-globin polymorphism allowed us to conclude that the analyzed tissues contained significant amounts of the tumor cells occurring in the C57BL/6NCr mice.

Animals↗
PubMed1985

Herpes simplex virus 1 mutant deleted in the alpha 22 gene: growth and gene expression in permissive and restrictive cells and establishment of latency in mice.

R325-beta TK+, a herpes simplex virus 1 mutant carrying a 500-base-pair deletion in the alpha 22 gene and the wild-type (beta) thymidine kinase (TK) gene, was previously shown to grow efficiently in HEp-2 and Vero cell lines. We report that in rodent cell lines exemplified by the Rat-1 line, plating efficiency was reduced and growth was multiplicity dependent. A similar multiplicity dependence for growth and lack of virus spread at low multiplicity was seen in resting, confluent human embryonic lung (HEL) cells. The shutoff of synthesis of beta proteins was delayed and the duration of synthesis of gamma proteins was extended in R325-beta TK+-infected HEL cells relative to cells infected with the wild-type parent, but no significant differences were seen in the total accumulation of viral DNA. To quantify the effect on late (gamma 2) gene expression, a recombinant carrying the deletion in the alpha 22 gene and a gamma 2-TK gene (R325-gamma 2 TK) was constructed and compared with a wild-type virus (R3112) carrying a chimeric gamma 2-TK gene. In Vero cells, the gamma 2-TK gene of R325-gamma 2TK was expressed earlier than and at the same level as the gamma 2-TK gene of R3112. In the confluent resting HEL cells, the expression of the gamma 2-TK gene of the alpha 22- virus was grossly reduced relative to that of the alpha 22+ virus. Electron microscopic studies indicated that the number of intranuclear capsids of R325-beta TK+ virus was reduced relative to that of the parent virus in resting confluent HEL cells, but the number of DNA-containing capsids was higher. Notwithstanding the grossly reduced neurovirulence on intracerebral inoculation in mice, R325-beta TK+ virus was able to establish latency in mice. We conclude that (i) the alpha 22 gene affects late (gamma 2) gene expression, and (ii) a host cell factor complements that function of the alpha 22 gene to a greater extent in HEp-2 and Vero cells than in confluent, resting HEL cells.

Animals↗
PubMed1985

Establishment of latency in mice by herpes simplex virus 1 recombinants that carry insertions affecting regulation of the thymidine kinase gene.

Herpes simplex virus 1 recombinants carrying alpha-, beta-, and late gamma (gamma 2)-regulated thymidine kinase (TK) genes were tested for the ability to establish latency in BALB/c mice inoculated by the eye route. The significant findings were as follows. Representatives of alpha- and gamma 2-regulated TK recombinants all established and maintained latent infections, but the efficiency was somewhat lower than that of wild-type virus. Of the three alpha TK recombinants tested, one (R316) spontaneously deleted portions of the inserted sequences which conferred alpha regulation to the TK gene. The viruses carrying these deletions expressed considerably lower TK activity than did wild-type virus, i.e., 2 to 40% of the levels expressed by the wild-type virus carrying the beta TK gene. However, the ability of these viruses to establish latency was not related to the efficiency of expression of the TK gene. These results indicate the following: (i) conversion of the TK gene into an alpha or gamma 2 gene did not preclude the establishment of latent infections; (ii) there was no correlation between the levels of TK activity expressed in cell culture and the ability to establish latency; and (iii) rearrangement of the genome by insertions or deletions which interrupt gene domains did not automatically result in an inability to establish latent infections.

Animals↗