Cytokines--a way towards better animal health.
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Animals↗
Biomedical subjects
M E Andrew
Publications and source records attributed to M E Andrew.
HIV risk behavior reduction following intervention with key opinion leaders of population: an experimental analysis.
BACKGROUND AND PURPOSE: Peer norms influence the adoption of behavior changes to reduce risk for HIV (human immunodeficiency virus) infection. By experimentally intervening at a community level to modify risk behavior norms, it may be possible to promote generalized reductions in HIV risk practices within a population. METHODS: We trained persons reliably identified as popular opinion leaders among gay men in a small city to serve as behavior change endorsers to their peers. The opinion leaders acquired social skills for making these endorsements and complied in talking frequently with friends and acquaintances. Before and after intervention, we conducted surveys of men patronizing gay clubs in the intervention city and in two matched comparison cities. RESULTS: In the intervention city, the proportion of men who engaged in any unprotected anal intercourse in a two-month period decreased from 36.9 percent to 27.5 percent (-25 percent from baseline), with a reduction from 27.1 percent to 19.0 percent (-30 percent from baseline) for unprotected receptive anal intercourse. Relative to baseline levels, there was a 16 percent increase in condom use during anal intercourse and an 18 percent decrease in the proportion of men with more than one sexual partner. Little or no change was observed among men in the comparison cities over the same period of time. CONCLUSIONS: Interventions that employ peer leaders to endorse change may produce or accelerate population behavior changes to lessen risk for HIV infection.
Community Participation↗
Elevated natural killer cell responses in mice infected with recombinant vaccinia virus encoding murine IL-2.
The role of cytotoxic T cells and NK cells in the recovery of immunodeficient, athymic, nude mice infected with a recombinant vaccinia virus (VV) encoding murine IL-2 was investigated. Kinetic studies with the IL-2-encoding recombinant (VV-HA-IL2) and control (VV-HA-TK) viruses excluded a role for cytotoxic T cells but suggested the possible involvement of NK cells. In athymic nude mice given VV-HA-IL2, NK activity was at least threefold higher than mice infected with VV-HA-TK and this activity persisted for at least 6 days after infection. The effectors mediating the NK-like activity were asialo-GM1+ (as-GM1+), Thy1.2+/-, CD4- and CD8-, the phenotype of conventional NK cells. Elevated NK activity coincided with the rapid clearance of VV-HA-IL2 from ovaries of infected normal CBA/H mice but not from ovaries of CBA beige mice which had no detectable NK activity in spleens or ovaries. The expression of IL-2 in recombinant VV infection probably induces a cascade of immunologic effects of which elevated NK activity is one. We speculate that the chemoattractant and NK activity augmenting effects of IL-2 may contribute to recovery from VV-infection.
Animals↗
Expression of bovine leukaemia virus envelope gene by recombinant vaccinia viruses.
Recombinant vaccinia viruses (VV) containing the envelope gene of bovine leukaemia virus (BLV) were constructed. Three virus constructs were designed: VV-BLV1 which contained the open reading frame for envelope glycoprotein gp51 alone, under control of VVP7.5 promoter; VV-BLV2 and VV-BLV3 contained the entire gene (gp51 + gp30) coding sequence downstream of VP7.5 and the fowlpox virus early/late promoter (PFE/L) respectively. All three VV recombinants expressed envelope glycoproteins as determined by the agar gel diffusion assay. By immunofluorescence techniques it was shown that while VV-BLV2 and VV-BLV3 expressed envelope glycoprotein on the surface of virus-infected cells, VV-BLV1 failed to do so. Rabbits inoculated with VV-BLV1 failed to show an anti envelope glycoprotein antibody response, however, significant levels of antibodies against envelope glycoprotein were detected in sera from rabbits inoculated with VV-BLV2 and VV-BLV3.
Animals↗
The immunogenicity of VP7, a rotavirus antigen resident in the endoplasmic reticulum, is enhanced by cell surface expression.
The glycoprotein VP7, the major serotype antigen of rotaviruses, is localized to the endoplasmic reticulum (ER) of the cell, where it is retained as a membrane-associated protein before assembly into mature virus particles. Wild-type VP7 expressed by a recombinant vaccinia virus was also located internally and was poorly antigenic. Using recombinant techniques, a correctly processed, secreted form of VP7 (S.C. Stirzaker and G.W. Both, Cell 56:741-747, 1989) was modified by addition to its C terminus of the membrane anchor and cytoplasmic domains from the influenza virus hemagglutinin. The hybrid protein was directed to the surface of cells, where it was anchored in the plasma membrane. When expressed in mice and rabbits by a recombinant vaccinia virus, the surface-anchored antigen stimulated a level of rotavirus-specific antibodies that was greater than 100-fold above the level induced by wild-type VP7. T-cell responses to the novel antigen were also elevated in comparison with the wild-type, intracellular protein. Cell surface anchoring may provide a strategy to increase the immunogenicity of intracellular antigens from other parasites and viruses.
Amino Acid Sequence↗
Stripping membranes at term: can it safely reduce the incidence of post-term pregnancies?
Membrane stripping has been used clinically for many years but has not been well studied. An investigation was undertaken to determine whether weekly membrane stripping beginning at 38 weeks could safely reduce post-term pregnancies. One hundred eighty patients with firm gestational dates were randomized to either a treatment or control group. Control subjects received a gentle cervicovaginal examination each week to assess Bishop scores, whereas the treatment group also underwent weekly stripping of membranes. Women who received treatment had earlier delivery (mean +/- SEM 8.60 +/- 0.74 versus 15.14 +/- 0.83 days; P less than .0001) and fewer post-term deliveries than those in the control group (three versus 14; P less than .004). The reduction of post-term pregnancies was most notable in nulliparous women with unfavorable Bishop scores. Complications were similar in both groups. Membrane stripping was safe and was associated with earlier delivery and a decreased incidence of post-term gestation.
Adult↗
Humoral and cell-mediated immune responses to recombinant vaccinia viruses in mice.
Intravenous (i.v.) immunization of mice with recombinant vaccinia viruses stimulated the highest antibody and cytotoxic T lymphocyte (CTL) responses when i.v., intraperitoneal (i.p.), intranasal (i.n.), footpad (f.p.) and tail scarification (t.s.) routes were compared. Intraperitoneal immunization of mice resulted in high CTL activity, but low antibody responses. Antibody levels after i.n., f.p., and t.s. immunization were slightly lower than following i.v. immunization. Although very low levels of CTL primary activity were stimulated by i.n. or f.p. inoculation of recombinant vaccinia virus, levels of secondary CTL activity after in vitro restimulation of splenocytes were as high as those seen from i.v. immunized splenocytes. The effect of the thymidine kinase (TK) phenotype of the virus also was examined. Wildtype (TK positive) viruses replicated to a higher titre in vivo and stimulated higher antibody and CTL responses than a TK negative recombinant virus. A recombinant virus that expressed the TK gene from herpes simplex virus at a low level was intermediate between wildtype and TK negative virus, both in virus replication in vivo and in immunogenicity.
Animals↗
Protective efficacy of a recombinant vaccinia virus in vaccinia-immune mice.
Recombinant viral vectors offer a potential means of vaccinating against diseases for which there are no current safe vaccines. One of the criteria on which a viral vaccine vector would be selected is that it either circulates in the human or livestock population without producing overt disease (e.g. adenovirus) or has a history as a safe vaccine (e.g. vaccinia virus). However, this selection criterion also means that the target population is likely to have circulating antibodies that are specific to the vaccine vector. Since a percentage of the world's population has been vaccinated during the World Health Organization's Smallpox Eradication Campaign, such antibody titres, which are likely to lower vaccine efficacy, have been raised as an objection to the use of recombinant vaccinia viruses as vaccines. We have tested the effect of vaccinia-specific immunity on the protective efficacy of a recombinant virus, VV-PR8-HA6 (1) which expresses the haemagglutinin of the influenza virus A/PR/8/34.
Animals↗
Recombinant vaccinia viruses and the development of immunization strategies using influenza virus.
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Animals↗
A general method for the construction of recombinant vaccinia viruses expressing multiple foreign genes.
Plasmid vectors with multiple cloning sites adjacent to a vaccinia virus (VV) promoter were constructed and used to insert a protein coding sequence and a dominant selectable marker into a non-essential region of the VV genome. Recombinant viruses, selected on the basis of expression of the herpes simplex virus (HSV) thymidine kinase gene (tk), were shown to express in infected cells the model gene product, murine major histocompatibility complex (MHC) antigen H-2Kd, by cell-surface binding of antibody and by MHC-restricted recognition by cytotoxic T lymphocytes. Double recombinant VVs with insertions at two sites (in the VV tk gene and in the VV HindIII-F region) were constructed and shown to express influenza A/PR/8/34 haemagglutinin and H-2Kd antigen in addition to the HSV tk gene. The plasmids described allow the construction of recombinant VV expressing two genes of interest under the control of the same VV promoter. Such recombinant VVs can be used to study the interaction of immunologically important antigens simultaneously expressed.
Animals↗
A crossover trial of bromocriptine in the treatment of vascular dementia.
Seven patients with vascular dementia completed an 8-month randomized double-blind crossover trial of bromocriptine in a dosage of up to 30 mg per day. Patients were assessed using a modified UCLA Parkinson Rating Scale of symptoms and signs, and neuropsychological testing including the Wechsler Adult Intelligence Scale-Revised, Wechsler Memory Scale, modified Thurstone Word Fluency Test, Wisconsin Card Sort, a test of visual vigilance, and a reaction time task. Subjects failed to perform significantly better on any measure while on bromocriptine, and on several measures their performance while on the drug was worse.
Aged↗
Class I MHC-restricted cytotoxic T cells efficiently recognize haemagglutinin that is defective in protein folding and cell surface expressions.
Cytotoxic T-cell recognition of an engineered variant of the influenza viral haemagglutinin (HA), expressed in vaccinia virus, was investigated. We show that the insertion of a Foot-and-Mouth Disease virus (FMDV) immunogenic peptide into the HA results in major disruption of its higher order structure with intracellular rather than cell surface localization accompanying the loss of conformational epitopes detected by antibody. In contradistinction to antibody, recognition of the chimaeric molecule by HA-specific class I-restricted cytotoxic T-cells was unimpaired, demonstrating that class I-specific T-cells recognize, in majority, continuous epitopes rather than conformational epitopes in the HA.
Animals↗
Efficacy of influenza haemagglutinin and nucleoprotein as protective antigens against influenza virus infection in mice.
Influenza nucleoprotein (NP)-specific cytotoxic T lymphocytes (CTL) stimulated by immunization of mice with VV-PR8-NP6, a recombinant vaccinia virus expressing A/PR/8/34 NP, did not protect mice against challenge with A/PR/8/34 4 days later. Neither were secondary NP-specific CTL stimulated by reimmunization able to protect mice. These results contrast with the ability of transferred, in vitro-cultured and stimulated, NP-specific CTL to protect recipient mice from challenge with A/PR/8/34. Immunization of mice with a recombinant vaccinia virus expressing A/PR/8/34 HA protected mice challenged 4 days later, either via the small amount of antibody already present, or via HA-specific CTL that would have to be more efficient than NP-specific CTL in either trafficking to the infected lung or in effector function.
Animals↗
Recognition by major histocompatibility complex class I-restricted cytolytic T lymphocytes of cells expressing vaccinia-encoded viral and class I proteins.
Target cells expressing influenza virus hemagglutinin (HA) could be recognized by cytotoxic T lymphocytes (CTL) in conjunction with the murine major histocompatibility complex class I antigen, H-2Kd, when both antigens were encoded by recombinant vaccinia virus. This recognition occurred if HA and H-2Kd were encoded by separate vaccinia viruses following dual infection of target cells or if HA and H-2Kd were encoded by a single recombinant virus. In contrast, target cells expressing nucleoprotein (NP) were only recognized by H-2Kd-restricted CTL if both NP and H-2Kd were encoded by the same vaccinia virus. These results show that the requirements for association of H-2Kd with different viral antigens derived from HA or NP can vary. Possible factors contributing to this difference are discussed.
Animals↗
The roles of influenza virus haemagglutinin and nucleoprotein in protection: analysis using vaccinia virus recombinants.
Vaccinia virus recombinants expressing haemagglutinin (HA) or nucleoprotein (NP) from influenza virus A/PR/8/34 were used to investigate protective immunity in mice, with two protocols. Protection was assessed by mortality and morbidity rates and by lung virus titres after infection intranasally with A/PR/8/34. In the first protocol, mice immunized with vaccinia-HA recombinant virus and infected intranasally with A/PR/8/34 were almost totally protected, but mice immunized with vaccinia-NP virus were very poorly protected. In the second protocol, the recombinant viruses were used to stimulate in vitro T cells that are specific for HA and NP; both populations of T cells, when transferred to A/PR/8/34-infected mice, afforded good protection. The results indicate that an immune response specific for just HA provided protection that was almost indistinguishable from that provided by whole A/PR/8/34. On the other hand, immunization with vaccinia-NP provided poor protective immunity, despite the fact that transferred NP-specific T cells were very effective and vaccinia-NP immunization has previously been shown to stimulate cytotoxic T cells. These results demonstrate that a single viral antigen, delivered by live vaccinia virus, can provide effective protection, but that immunization for cross-protection against heterologous influenza virus remains elusive.
Animals↗
Vaccinia virus recombinants expressing the SA11 rotavirus VP7 glycoprotein gene induce serotype-specific neutralizing antibodies.
A cDNA copy of the gene coding for the major outer neutralizing protein (VP7) of simian 11 rotavirus was incorporated into the vaccinia virus genome under the control of the vaccinia promoter (molecular weight, 7,500). A deletion mutant of this gene which codes for a secreted form of VP7 when expressed under the control of the simian virus 40 late promoter (M. S. Poruschynsky, C. Tyndall, G. W. Both, F. Sato, A. R. Bellamy, and P. H. Atkinson, J. Cell Biol. 101:2199-2209, 1985) was also inserted. Each recombinant vaccinia virus directed the synthesis of a rotavirus protein in infected cells, and the product encoded by the mutated gene was secreted. Rabbits immunized with the two types of recombinant vaccinia virus generated antibodies that were able both to recognize simian 11 rotavirus in an enzyme-linked immunosorbent assay and to neutralize the virus in a plaque-reduction test. Antibodies induced by the recombinant vaccinia viruses expressing either form of VP7 were serotype specific.
Antibodies, Viral↗
Temporal regulation of influenza hemagglutinin expression in vaccinia virus recombinants and effects on the immune response.
Regulation of the expression of influenza A/PR/8/34 hemagglutinin (HA) by the vaccinia virus promoters PF (early), P7.5 (early and late) and PL11 (late) has been demonstrated using HA-vaccinia recombinant viruses VV-PR8-HA3, VV-PR8-HA6 and VV-PR8-HA, respectively. Levels of HA on the surface of VV-PR8-HA3 (PF)-infected cells were lower than with either VV-PR8-HA6 (P7.5) or VV-PR8-HA8 (PL11). Expression of HA under the control of the late promoter PL11 was inhibited in the absence of DNA replication. All three recombinant viruses stimulated a specific antibody response in mice which was dependent on the presence of infectious virus. Recognition of HA by cytotoxic T lymphocytes (CTL) was assessed by the ability of the viruses to stimulate naive precursors in vivo, to restimulate primed CTL in vitro and by target cell recognition. HA expressed under the control of either of the promoters with early function (PF or P7.5) was recognized by CTL when VV-PR8-HA3 or VV-PR8-HA6 were used to prime or restimulate splenocytes or to infect target cells. On the other hand, HA expressed by VV-PR8-HA8 (PL11) failed to prime for a CTL response in naive CBA/H mice, was ineffective at restimulation of primed splenocytes and failed to produce target cells for recognition by specific CTL. However, in BALB/c mice VV-PR8-HA8 did prime for a specific CTL response. These studies show that HA synthesized early in infection was recognized by both B and T cells while HA expressed after DNA replication was not generally recognized by T cells. The implications of the observations with the late promoter with respect to the use of late promoters in potential vaccinia virus-based vaccines are considered.
Animals↗
Cell-mediated immune responses to influenza virus antigens expressed by vaccinia virus recombinants.
Recombinant vaccinia viruses enable studies of immune recognition of antigens expressed from single viral genes. We have constructed recombinants expressing the haemagglutinin (HA) and nucleoprotein (NP) genes of the influenza virus A/PR/8/34 (H1N1). These recombinant viruses together with a recombinant expressing the HA from influenza virus A/JAP/305/57 (H2N2) have been used to examine the cytotoxic T lymphocyte (CTL) response to these influenza virus antigens. Both antigens are recognised by murine CTL and recognition of HA is influenza virus subtype-specific, whereas recognition of NP is crossreactive. In limiting dilution studies approximately 10% of the influenza CTL response is HA-specific, while approximately 30% of the response is NP-specific. Despite the ability of NP to stimulate a significant CTL response, mice immunised with the NP-vaccinia recombinant are not as well protected from subsequent lethal challenge with influenza virus, as mice immunised with the HA vaccinia recombinant. These studies demonstrate that viral antigens expressed from vaccine recombinants can provide protective immunity and that the influenza-poxvirus recombinants can provide data on protective immunity generated by individual viral proteins.
Animals↗