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Biomedical subjects

B Morein

Publications and source records attributed to B Morein.

At least 19 recordsLinked to original sources
PubMed1992

An immune stimulating complex (ISCOM) subunit rabies vaccine protects dogs and mice against street rabies challenge.

Dogs and mice were immunized with either a rabies glycoprotein subunit vaccine incorporated into an immune stimulating complex (ISCOM) or a commercial human diploid cell vaccine (HDCV) prepared from a Pitman Moore (PM) rabies vaccine strain. Pre-exposure vaccination of mice with two intraperitoneal (i.p.) doses of 360 ng ISCOM or 0.5 ml HDCV protected 95% (38/40) and 90% (36/40) of mice, respectively, against a lethal intracerebral (i.c.) dose with challenge virus strain (CVS). One 360 ng i.p. dose of ISCOM protected 87.5% (35/40) of mice against i.c. challenge with CVS. Three groups of five dogs were vaccinated intramuscularly (i.m.) with 730 ng of rabies ISCOM prepared from either the PM or the CVS rabies strains, and they resisted lethal street rabies challenge. Postexposure treatment of mice with three or four 120 ng i.m. doses of ISCOM protected 90% (27/30) and 94% (45/48), respectively, of mice inoculated in the footpad with street rabies virus, but three doses of HDCV conferred no protection. When four doses of HDCV were administered postexposure, 78% (32/41) of the mice died of anaphylactic shock; 21% (11/52) of mice had already died of rabies 4 days after the third vaccine dose was administered.

Animals↗
PubMed1992

Comparison of protection afforded by whole virus ISCOM versus MDP adjuvanted formalin-inactivated SIV vaccines from IV cell-free or cell-associated homologous challenge.

A SIV-ISCOM and a SIV-MDP adjuvanted vaccine were tested for their potential to induce protection from intravenous cell-free or cell-associated homologous SIV challenge in rhesus monkeys (Macaca mulatta). Seven monkeys vaccinated four times over a four-month period with either the SIV-ISCOM or the SIV-MDP vaccine were challenged intravenously with approximately 10 MID50 cell-free SIVmac251 (32H). They all were protected from developing viremia during a three-month observation period. Two other groups of four monkeys were vaccinated essentially in the same way with either of these vaccines. They were challenged intravenously with approximately 10 MID50 of infected PBMC of a rhesus monkey that had been infected with SIVmac251 (32H) 11 months earlier (stock prepared by J. Heeney). Two monkeys of each of these two groups proved to be protected from developing viremia during a two-month observation period. For both the cell-free and the cell-associated SIV challenge, monkeys vaccinated with measles virus ISCOMS or MDP adjuvanted measles virus antigen, served as controls. They all became viremic within two weeks after SIV challenge. This is the first demonstration that vaccinated previously unchallenged nonhuman primates can be protected from infection with lentivirus-infected PBMC from another animal. Serological analysis indicated that SIV-specific serum antibody titers were considerably higher in SIV-ISCOM vaccinated animals than in the SIV-MDP vaccinated animals. The serology also confirmed the protection data, by showing the absence of increase in SIV-specific serum antibodies in apparently protected animals after challenge.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Interactions between immune-stimulating complexes (ISCOMs) and peritoneal mononuclear leucocytes.

Studies were undertaken in mice using immune-stimulating complexes (ISCOMs) or micelles prepared from envelope glycoproteins of human influenza virus (PR8) and matrix (i.e., ISCOM skeleton without incorporated antigen). Electron microscopic studies showed that ISCOMs, in contrast to micelles, have a remarkable affinity for cell membranes and seem to rapidly promote their own internalization by cells to which they adhere. PR8 ISCOMs, but not matrix nor micelles, significantly increased the expression of membrane Ia by peritoneal mononuclear leucocytes 24 hr after intraperitoneal immunization.

Animals↗
PubMed1992

Involvement of interleukin-2 and interferon-gamma in the immune response induced by influenza virus iscoms.

Splenocytes from mice primed with influenza virus envelope proteins incorporated in iscoms, as micelles or as infectious virus, were restimulated in vitro with the same antigen. Interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were assayed in the supernatants of such cultures. Influenza virus iscoms induced IL-2 and IFN-gamma responses in restimulation experiments that were antigen specific and significantly higher than those induced by micelles or infectious virus. Serum samples collected at the end of the experiments were analysed for the antibody response and profile. The antibody titres induced by iscoms were of a similar order of magnitude as those induced by infectious virus, and were about 18 times higher than the titres induced by micelles. In mice immunized with iscoms or infectious virus the most abundant antibodies were of the IgG1 and IgG2a isotype, and the IgE response was low. We conclude that immunization with iscoms stimulates the Th1-like subtype of murine T lymphocytes.

Animals↗
PubMed1992

Antigen-specific increases in the number of splenocytes expressing MHC class II molecules following restimulation with antigen in various physical forms.

To understand how a presentation system for antigens initiates an immune response and why it has a strong adjuvant activity, a number of parameters need to be analysed. In this study the frequency of spleen cells expressing MHC class II (Ia antigen) was determined after immunization of mice and restimulation of their spleen cells, in vitro, with influenza virus envelope proteins in different physical forms, namely iscoms, micelles and virus particles. All three forms of the antigen stimulated, in an antigen-specific manner, an increased proportion of spleen cells expressing MHC class II in the restimulation experiments. The induction of increased MHC class II expression was at least partly dependent on antigen-specific induction of IFN-gamma since an antibody to IFN-gamma partly inhibited the increase of MHC class II+ cells induced by iscom or by Concanavalin A. The iscom-borne antigens were superior to micelles to prime the immune response in vitro, indicating a capacity to induce memory cells. This primed immune response was readily recalled in vitro, as measured by IFN-gamma production and an increased number of MHC class II positive cells.

Animals↗
PubMed1991

Characterization of purified gp 51 from bovine leukemia virus integrated into iscom. Physicochemical properties and serum antibody response to the integrated gp51.

It is proposed that the envelope glycoprotein, gp 51, is the protective antigen of bovine leukemia virus (BLV). An experimental iscom vaccine has been prepared from immunoaffinity purified gp 51. To overcome the problem of integrating a nonamphipathic protein, gp 51 was partially denatured at pH 2.4 before integration into the iscom. The recovery of gp 51 into the iscom was calculated to be 85%. The gp 51 incorporated into iscom retained its physicochemical properties and the neutralizing epitopes F, G and H were found to be intact. The iscom preparation was shown to induce a specific immune response to gp 51 after inoculation into mice and calves, as tested by ELISA and Western blotting. Sera from the immunized calves specifically inhibited the VSV-(BLV) pseudotypes. Thus the gp 51-iscom preparations appear to be highly immunogenic and to induce a gp 51 specific response.

Animals↗
PubMed1991

Immunoaffinity purification of two major proteins of bovine leukemia virus (gp51 and p24) and their use for discrimination between vaccinated and infected animals.

The outer envelope glycoprotein gp51 and the core protein p24 of bovine leukemia virus (BLV), were purified from culture media of FLK-BLV cells by a single-step procedure, using immunoaffinity chromatography based on monoclonal antibodies to the respective proteins. About 90% of the envelope glycoprotein in the culture medium was recovered as a highly purified product. Both purified protein (gp51 and p24) preparations, were found to be highly specific antigens by ELISA, and did not cross-react with sera raised against the other antigen. The conformational epitopes on the purified gp51 were preserved as judged by their reactions with the corresponding monoclonal antibodies. The p24 ELISA reacted only with sera from naturally infected animals and not with sera from animals immunized with an experimental gp51-iscom vaccine. The p24 antigen is therefore useful for discriminating between BLV-infected animals and those immunized with a gp51 subunit vaccine.

Animals↗
PubMed1991

Cross-neutralizing antibodies to HIV-1 in mice after immunization with gp160 iscoms. Dissection of the immune response.

Gp160 expressed in vaccinia and produced in vero cells was integrated into iscoms. Gp160 iscoms elicited a high serum antibody response in mice, and after two immunizations a ceiling was reached. The serum antibody response was dissected by the use of defined recombinant DNA products, representing different regions of the gp160 molecule. High antibody titers to the peptid RP135 (a.a. 296-332) correlated with induction of neutralizing serum antibodies. In some animals, gp160 (IIIB) iscoms elicited cross-neutralizing antibodies that also neutralized the distantly related RF isolate.

AIDS Vaccines↗
PubMed1991

Cross-neutralizing antibodies in rabbits immunized with HIV-1 gp160 purified from simian cells infected with a recombinant vaccinia virus.

A recombinant vaccinia virus in which the transcription of the human immunodeficiency virus type 1 (BRU isolate) env gene is driven by the 11K late vaccinia promoter yields about 10-fold higher amounts of gp160 env protein upon infection of monkey cells than does a recombinant in which gp160 is expressed using the 7.5K early-late promoter. The gp160 was purified from detergent lysates of infected cells by lentil lectin affinity chromatography followed by immunoaffinity chromatography, and was obtained in yields of 1-2 mg/10(9) cells of material estimated to be about 70% pure. Pairs of rabbits were immunized with purified gp160 using either one of five different adjuvants or an immunostimulating complex. In all cases a substantial humoral immune response was obtained after boosting, including an activity that neutralized the homologous (BRU) isolate of HIV-1. In some cases, this activity also neutralized two distantly related isolates, SF2 and MN.

Animals↗
PubMed1991

ISCOM of BHV-1 envelope glycoproteins protected calves against both disease and infection.

A subunit vaccine in the form of immunostimulating complex (iscom) was prepared to contain the envelope glycoproteins of bovine herpesvirus type 1 (BHV-1). This iscom preparation was tested in a vaccination experiment on 4-month-old calves seronegative to BHV-1. In this experiment, four groups with three animals per group were used. Two groups were vaccinated with the iscom preparation twice, four weeks apart, one group with 50 micrograms and the other with 100 micrograms per calf. The third group received a commercial inactivated whole-virus vaccine applying the same vaccination program. The fourth group served as control. Two weeks after the second vaccination, all the animals were challenge-infected intranasally with a virulent BHV-1 strain and four days later with a virulent Pasteurella multocida--this in order to mimic hard field conditions. When exposed to challenge infection, all the animals vaccinated with the iscom were fully protected, i.e., no virus could be recovered from their nasal secretions and no clinical symptoms were recorded. In contrast, the animals vaccinated with the commercial vaccine, responded to challenge with moderate fever and loss of appetite, and virus was isolated from the nasal secretions. The animals in the control group developed severe clinical symptoms. In the sera of iscom-vaccinated animals, the virus neutralization titers reached levels of 1/3500 or higher.

Adjuvants, Immunologic↗
PubMed1991

Immunization with Trypanosoma cruzi epimastigote antigens incorporated into iscoms protects against lethal challenge in mice.

An immunoglobulin G3 monoclonal antibody obtained by immunizing mice with a cell membrane preparation of epimastigotes of Trypanosoma cruzi was shown to agglutinate live epimastigotes, lyse blood-form trypanosomes, and partially protect mice by passive transfer. The main antigens recognized by the monoclonal antibody were located in the flagella of epimastigotes and blood-form trypanosomes. Antigens of epimastigotes, purified by affinity chromatography with the monoclonal antibody, were shown to be highly glycosylated and revealed a wide band with an Mr between 45,000 and 68,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Immunization of mice with a small concentration of the affinity purified antigens incorporated into an antigen delivery system prepared with Quil A (Isotec AB, Lulea, Sweden), a saponin derivative, induced strong antibody and cell-mediated immune responses and protected 100% of the immunized animals against death due to challenge with 100 100% lethal doses of blood form trypanosomes. Protection was due to the use of the antigen delivery system, since mice immunized with equal concentrations of antigens alone or in combination with saponin had 100% mortality. The results suggest that small concentrations of epimastigote antigens obtained by biochemical methods and incorporated into the proper antigen delivery system may serve as a vaccine against Chagas' disease.

Adjuvants, Immunologic↗
PubMed1991

Vaccination against herpesvirus, fiction or reality?

Against Herpes simplex type 1 (HSV-1) there are commercially available vaccines which may induce protection against symptoms of primary infections, but not against establishment of latency. Effective animal vaccines have been developed against herpes simplex-like viruses, for example pseudorabies vaccine for pigs, and an experimental vaccine can protect cattle against infection with infectious bovine rhinotracheitis (IBR) virus. There are also commercially available effective live vaccines against Marek's disease virus which belongs to the lymphoproliferative group of herpesviruses and causes lymphoma in chicken. An experimental immunostimulating complex (iscom) vaccine against Equine herpesvirus 2, an equine cytomegalovirus, has been tested in horse and protective immunity was induced. In man vaccines against Cytomegalovirus are used in immunosuppressed patients. Several laboratory animal models have been created for HSV-1 and HSV-2 mostly using mice but also guinea pigs. In these models many different HSV-1 or HSV-2 vaccines have been tested and induced protective immunity. The antigens in the vaccines have been envelope proteins extracted from native virus or envelope glycoproteins gB or gD in single or combined use. Glycoprotein C seems to be a less interesting as antigen for a HSV-1 vaccine. The cottontop tamarin monkey has been studied as a model for Epstein-Barr virus (EBV) induced lymphoma. An iscom vaccine containing the envelop protein gp340 of EBV induced full protection in the cottontop tamarins against a challenge infection. The iscom vaccine concept is discussed and the formation of an iscom particle with "tailor made" antigens and immunomodulators is presented.

Animals↗
PubMed1990

Induction of CD8+ cytotoxic T cells by immunization with purified HIV-1 envelope protein in ISCOMs.

To reduce the risks of immunization with killed or live attenuated virus vaccines, it may be advantageous to use a pure, defined antigen that contains determinants for both humoral and cellular immunity. However, although most non-living intact protein preparations induce antibodies and CD4+ major histocompatibility complex (MHC) class II-restricted helper and/or cytotoxic T lymphocytes (CTL), they do not elicit CD8+ MHC class I restricted CTL. Indeed, with a few exceptions, it has not so far been possible to induce CD8+ CTL by immunizing with intact soluble proteins. We show here that a single subcutaneous immunization in mice with immunostimulating complexes containing either purified intact gp160 envelope glycoprotein of the human immunodeficiency virus (HIV)-1 or influenza haemagglutinin results in reproducible and long-lasting priming of HIV specific or influenza-specific CD8+, MHC class I restricted CTL.

Adjuvants, Immunologic↗
PubMed1990

Increased immunogenicity of a non-amphipathic protein (BSA) after inclusion into iscoms.

Bovine serum albumin (BSA) was used as a non-amphipathic model protein to be included into iscoms. Pretreatment at an acidic pH (2.5) was used to reveal hydrophobic regions, after which BSA could be integrated. In immunization experiments in mice the BSA iscoms induced long lasting and considerably higher serum antibody responses than non-treated monomeric BSA or BSA aggregated by acidic treatment.

Animals↗
PubMed1990

Effect of iscoms and their adjuvant moiety (matrix) on the initial proliferation and IL-2 responses: comparison of spleen cells from mice inoculated with iscoms and/or matrix.

In the iscom, antigen is attached by hydrophobic interactions to a matrix which is built up by the adjuvant Quil A and lipids. Thus, the iscom presents antigen in multiple copies on a small particle with a built-in adjuvant. By studying the specific antibody response, in vitro proliferation and IL-2 secretion by splenocytes from mice following different in vivo treatments with iscoms and/or matrix, we attempted to distinguish between nonspecific stimulatory effects, caused by the matrix or iscoms, and specific responses to the antigens incorporated into iscoms. The results strongly suggest that matrix and also iscoms exert a nonspecific adjuvant activity by a transient high spontaneous proliferation of cells collected within 2 weeks after administration of iscoms or matrix. This high rate of proliferation was preceded by suppressed proliferation, 3 days after injection with matrix or iscom. The adjuvant component included in iscoms, i.e., the matrix, does not excert a mitogenic stimulation in vitro or influence the levels of specific antibodies in serum. Specific responses to the antigens included in iscoms were recorded both as increasing levels of serum antibodies and as iscom-induced proliferation of immune spleen cells in vitro. The recruitment of IL-2 was only related to the specific stimulation induced by the antigens in iscom.

Adjuvants, Immunologic↗
PubMed1990

The iscom: an immunostimulating system.

To make purified antigens highly immunogenic, they have to be presented in several copies in the form of a microscopic or submicroscopic particle. This is the case, regardless of whether the antigens are obtained by isolation from conventional microorganisms, or from gene-manipulated cells, or synthesized. In the iscom, the antigens are attached as multimers to a 40-nm cage-like particle with a built-in adjuvant. The antigens in iscoms are rapidly transported from the injection site to the draining lymphatic organ. Iscom-borne antigens induced a 10-fold higher antibody response than the same amount of antigen in micelle form. One intranasal immunization with influenza virus iscoms induced protection to intranasal challenge infection in mice. Besides a strong antibody response in all Ig classes and isotypes, cytotoxic T cells were induced. With iscoms containing gp160 of HIV-1, cytotoxic T cells (CD8+ CD4-) were induced under restriction of class I MHC antigen. Iscoms containing the fusion protein of measles virus induced T cell clones in mice whereof one, after adoptive transfer, protected mice against intracerebral challenge infection. Protective immunity against Epstein-Barr virus (EBV)-induced tumor formation by iscoms containing gp350 of EBV has been elicited in cotton-top Tamerin monkeys. Protective immunity has also been induced against several virus infections including feline leukemia virus and against parasites, i.e., Trypanosoma cruzi, in mice.

Adjuvants, Immunologic↗
PubMed1990

Vaccination of Balb/c mice against enteroviral mediated myocarditis.

A non-virulent strain of Coxsackie B3 (CB3) virus was used to produce a subunit vaccine. It contains the capsid proteins VP1, 2, 3 and probably 4 and can be made RNA-free. It is based on the ISCOM technology ensuring non-toxic properties and good adjuvant effect. Vaccinated animals at doses above 16 ng were completely protected from mortality when challenged with a myocarditic strain of CB3. Histologically no inflammatory lesions were found in the heart. This was corroborated using immune histological techniques with monoclonal antibodies against lymphocyte subsets. Even at a dose of 0.16 ng a delayed mortality was observed. Neutralizing antibody titres rose to 512, thus ensuring a circulating level well above that considered protective. It is suggested that vaccination might be a possible way of prophylaxis for myocarditis and even dilated cardiomyopathy, the latter presently being the chief cause of heart transplantation. By persistence or triggering of autoimmune phenomena Coxsackie virus is incriminated as the first step in pathogenesis.

Animals↗