http://repub.eur.nl/res/aut/454/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/3722/ 2000-05-01T00:00:00Z Semipurified Quil A and purified Quil A were used to prepare well-characterized subunit vaccine candidates against measles. Variation in the relative amounts of the measles virus (MV) fusion (F) protein, Quil A-components and lipids did not influence induction of antibody responses in mice, but had a pronounced effect on the capacity to induce cytotoxic T cell (CTL) activity of a CD8(+) MV F-protein specific human T cell clone in vitro. A characteristic MV iscom preparation based on the combined use of HPLC-purified Quil A-components QA-3 and QA-22 (QA-3/22) efficiently induced CTL activity in vitro. Comparable results were obtained by mixing beta-propiolactone inactivated MV with iscom-matrix QA-3/22 or free QA-22. On the basis of the data presented it was concluded that these three preparations are interesting MV vaccine candidates for further evaluation in pre-clinical experiments in a primate model. http://repub.eur.nl/res/pub/3547/ 1995-01-01T00:00:00Z Shortly after infection of two rhesus monkeys (Macaca mulatta) either with a SIVmac32H challenge stock or with the same virus that had been passaged in another rhesus monkey for 11 months, SIV-envelope genes were cloned from their peripheral blood mononuclear cells and subsequently expressed by recombinant vaccinia viruses. The molecular weights and antigenicities of the thus produced envelope glycoproteins were largely identical to those of the native SIV. The envelope glycoprotein derived from the in vivo passaged virus proved to be poorly recognized by virus neutralizing monoclonal antibodies directed against one of the seven antigenic sites for which monoclonal antibodies were available. Immunization studies in rats showed that this protein was also less efficient in inducing antibodies against this antigenic site, and that it induced significantly lower levels of virus neutralizing antibodies than the other SIV-envelope glycoprotein. The immunogenicity of the SIV-envelope glycoprotein incorporated into immune stimulating complexes (iscoms) was compared to that of the same protein presented with Quil A or MDP-tsl. http://repub.eur.nl/res/pub/3552/ 1995-01-01T00:00:00Z To gain further insight into the ability of subunit vaccines to protect monkeys from experimental infection with simian immunodeficiency virus (SIV), two groups of cynomolgus macaques were immunized with either recombinant SIVmac32H-derived envelope glycoproteins (Env) incorporated into immune-stimulating complexes (iscoms) (group A) or with these SIV Env iscoms in combination with p27gag iscoms and three Nef lipopeptides (group B). Four monkeys immunized with recombinant feline immunodeficiency virus Env iscoms served as controls (group C). Animals were immunized intramuscularly at weeks 0, 4, 10, and 16. Two weeks after the last immunization, monkeys were challenged intravenously with 50 monkey 50% infectious doses of virus derived from the J5 molecular clone of SIVmac32H propagated in monkey peripheral blood mononuclear cells. High titers of SIV-neutralizing antibodies were induced in the monkeys of groups A and B. In addition, p27gag-specific antibodies were detected in the monkeys of group B. Vaccine-induced cytotoxic-T-lymphocyte precursors against Env, Gag, and Nef were detected on the day of challenge in the monkeys of group B. Env-specific cytotoxic-T-lymphocyte precursors were detected in one monkey from group A. In spite of the observed antibody and T-cell responses, none of the monkeys was protected from experimental infection. In addition, longitudinal determination of cell-associated virus loads at weeks 2, 4, 6, 9, and 12 postchallenge revealed no significant differences between vaccinated and control monkeys. These findings illustrate the need to clarify the roles of the different arms of the immune system in conferring protection against primate lentivirus infections. http://repub.eur.nl/res/pub/3510/ 1994-11-11T00:00:00Z The immunogenicity and efficacy of an inactivated whole SIVmac (32H) preparation adjuvanted with muramyl dipeptide (SIV-MDP) and a gp120-enriched SIVmac (32H) ISCOM preparation (SIV-ISCOM), were compared by immunizing four rhesus macaques (Macaca mulatta) four times with SIV-MDP and four others in the same way with SIV-ISCOM. Two monkeys immunized with whole inactivated measles virus (MV) adjuvanted with MDP (MV-MDP) and two monkeys immunized with MV-ISCOM served as controls. In the SIV-ISCOM-immunized monkeys higher SIV-specific serum antibody titres were found than in the SIV-MDP-immunized monkeys. In contrast to the MV-immunized monkeys all SIV-MDP- and SIV-ISCOM-immunized monkeys were protected against intravenous challenge 2 weeks after the last immunization with 10 median monkey infectious doses (MID50) of a cell-free SIVmac (32H) challenge stock propagated in the human T-cell line C8166. After 43 weeks the protected monkeys were reboosted and 2 weeks later rechallenged with 10 MID50 of the same virus produced in peripheral blood mononuclear cells (PBMC) from a rhesus macaque. None of these animals proved to be protected against this challenge. In a parallel experiment in which the same numbers of monkeys were immunized in the same way, the animals were challenged intravenously with 10 MID50 of PBMC from an SIVmac (32H)-infected rhesus macaque. Two out of four SIV-MDP- and two out of four SIV-ISCOM-immunized monkeys proved to be protected from SIV infection. http://repub.eur.nl/res/pub/3435/ 1992-01-01T00:00:00Z http://repub.eur.nl/res/pub/3438/ 1992-01-01T00:00:00Z Several viruses may cause more or less severe acute respiratory infections in man, some of which are followed by systemic infection. Only for influenza and measles are licensed vaccines available at present. The protection induced by influenza vaccines, which are based on inactivated whole virus or viral subunits, depends largely on the matching of vaccine strain and circulating virus. Measles vaccines, which are based on attenuated live virus, have been quite effective in controlling the disease in vaccinated populations in the industrialized world. In developing countries, severe measles infections occur in infants from six to nine months of age, which necessitates the vaccination of children of less than six months. At that time maternal antibodies, that may interfere with the induction of protection, may still be present. Therefore, instead of using the parenteral route, the possibility to use the mucosal route of primary immunization is also investigated for vaccination with attenuated live measles vaccines. The use of inactivated measles vaccines has resulted in a state of immunity which upon exposure to the virus may induce an atypical measles syndrome including a severe pneumonia. Measles virus proteins presented in an iscom matrix have recently been shown to induce functional B and T cell responses to both the surface glycoproteins of the virus. These responses could also be induced in the presence of virus neutralizing antibodies and they proved to be protective in several animal model systems. Many of the problems that have been encountered in the development of measles vaccines, proved to be similar in the development of vaccines against other paramyxoviruses causing acute respiratory infections in man, including respiratory syncytial virus. Parenteral application of inactivated and attenuated live vaccines against these paramyxoviruses has generally had little success. Topical application of attenuated live vaccines has been more successful, and also the use of vaccinia recombinant viruses expressing foreign paramyxoviral glycoproteins has shown promising results in laboratory animals. Live vaccines based on adenovirus types 4 and 7 in oral enteric-coated vaccines, which lead to virus replication in the intestines but not in the respiratory tract have been included in military vaccination programs. The possibility to replace e.g. the E3 region with foreign DNA makes adenoviruses also suitable as cloning vectors for proteins of other respiratory viruses. Although live attenuated vaccines against some of the serotypes of rhinoviruses have shown promising results, the generation of a multivalent vaccine against this epidemiologically most significant cause of acute respiratory infections will be almost impossible, due to the multiplicity of serotypes involved.(ABSTRACT TRUNCATED AT 400 WORDS) http://repub.eur.nl/res/pub/3444/ 1992-01-01T00:00:00Z This study attempted to determine if SIV vaccines could protect against challenge with peripheral blood mononuclear cells (PBMCs) from an SIV infected rhesus monkey. Mature Macaca mulatta were vaccinated four times with formalin inactivated SIVmac32H administered in MDP adjuvant (n = 8) or SIVmac32H ISCOM vaccine (n = 8). Controls included animals vaccinated with measles virus in MDP adjuvant (n = 4) or ISCOM (n = 4) preparations. Of each group, half were challenged intravenously (IV) with ten MID50 of the cell-free SIVmac32H (11-88) SIV stock and half were challenged with ten MID50 of PBMCs from the SIVmac32H infected macaque 1XC. All SIV vaccinated animals challenged with the 11-88 cell free stock of SIVmac32H were protected, whereas only half of the SIV vaccinated monkeys receiving the same infectious dose of the 1XC cell stock were protected. http://repub.eur.nl/res/pub/3445/ 1992-01-01T00:00:00Z The routes used by antigen-presenting cells (APC) to convert the transmembrane fusion glycoprotein (F) of measles virus (MV) to HLA class I and class II presentable peptides have been examined, using cloned cytotoxic T lymphocytes in functional assays. Presentation by Epstein-Barr virus-transformed B lymphoblastoid cell lines was achieved using live virus, ultraviolet light-inactivated virus, and purified MV-F delivered either as such or incorporated in immunostimulating complexes (MV-F-ISCOM). Only live virus and MV-F-ISCOM allow presentation by class I molecules, while all antigen preparations permit class II-restricted presentation. We observe presentation of MV-F from live virus and as MV-F-ISCOM by class II molecules in a fashion that is not perturbed by chloroquine. Our studies visualize novel presentation pathways of type I transmembrane proteins. http://repub.eur.nl/res/pub/3401/ 1990-09-24T00:00:00Z During a recent disease outbreak among harbour seals (Phoca vitulina) in the North and Baltic seas, more than 17,000 animals have died. The clinical symptoms and pathological findings were similar to those of distemper in dogs. Based on a seroepizootiological study, using a canine distemper virus (CDV) neutralization assay, it was shown that CDV or a closely related morbillivirus (phocid distemper virus-PDV) was the primary cause of the disease. The virus was isolated in cell culture from the organs of dead seals and characterized as a morbillivirus by serology (immunofluorescence neutralization and enzyme-linked immunosorbent assays) and by negative contrast electron microscopy. Experimental infection of SPF dogs resulted in the development of mild clinical signs of distemper and CDV-neutralizing antibodies. The disease was reproduced in seals by experimental inoculation of organ material from animals that had died during the outbreak. However, seals that had been vaccinated with experimental inactivated CDV vaccines were protected against this challenge. This fulfilled the last of Koch's postulates, confirming that the morbillivirus isolated from the seal organs, was the primary cause of the disease outbreak. The recent demonstration of the presence of a similar virus in Lake Baikal seals (Phoca sibirica), which infected these Siberian seals 1 year before the northwestern European seals were infected, raises new questions about the origin of this infectious disease in pinnipeds. http://repub.eur.nl/res/pub/3363/ 1989-04-15T00:00:00Z Measles virus (MV)-specific murine helper T cell clones (Thy-1.2+, CD4+, CD8-) were generated from mice immunized with MV-infected mouse brain homogenate by limiting dilution and in vitro stimulation of spleen cells with UV-inactivated MV Ag. The protein specificity of 7 out of 37 stable T cell clones, which displayed MHC-restricted MV Ag recognition, could be assessed by using purified MV proteins. Two fusion (F) protein-specific, two hemagglutinin-specific, and three nucleoprotein- or matrix protein-specific clones were shown to be established. The F protein-specific T cell clones together with a panel of previously generated F protein-specific T cell clones were characterized for their fine specificity by using beta-galactosidase fusion products, which contained different parts of the F protein. It was shown that at least two epitopes on the major part of the F protein (amino acid 2-513) can be recognized by mouse T cells. Functional characterization of three T cell clones showed that they were able to assist MV-specific B cells and bystander B cells for antibody production. Furthermore, they were shown to produce the lymphokines IL-2 and IFN-gamma. It was also shown that these T cell clones induced a MV-specific delayed type hypersensitivity response. These observations suggest that all of the T cell clones characterized belong to the TH1 helper subset. http://repub.eur.nl/res/pub/3379/ 1989-01-01T00:00:00Z Two inactivated canine distemper virus (CDV) vaccines--an adjuvanted whole inactivated virus and a subunit ISCOM preparation--were tested for their ability to induce protective immunity in harbour seals (Phoca vitulina) against phocid distemper, a disease that recently killed greater than 17,000 harbour seals in the North and Baltic seas, and was shown to be caused by infection with a newly discovered morbillivirus, which is antigenically closely related to CDV. Four CDV seronegative harbour seals were vaccinated three times with the whole-virus vaccine, two with the ISCOM subunit vaccine and two were sham-vaccinated with an antigen-free preparation. Ten days after the last vaccination, when all six vaccinated animals had developed CDV neutralizing antibody titres ranging from 300 to 3000, all eight animals were challenged by the oculonasal and the peritoneal routes, with an organ suspension from dead seals. None of the six vaccinated animals developed clinical signs. The two sham-vaccinated seals died on days 14 and 18, respectively, after having shown a body temperature rise, respiratory symptoms and weight loss. In organs from both dead animals morbillivirus antigen was demonstrated with an enzyme-linked immunosorbent assay and an immunofluorescence assay. One of these two animals had developed a low titre of CDV-specific antibodies just before death. These data clearly indicate that seals can be protected from fatal challenge with the phocid distemper virus (PDV), by vaccination with certain inactivated CDV vaccines. They also reconfirm that infection with PDV should be considered the primary cause of the recent epizootic in seals. http://repub.eur.nl/res/pub/3339/ 1988-01-01T00:00:00Z The potential of immune-stimulating complexes (iscoms), a novel form of antigenic presentation, for the induction of protective immunity against morbillivirus infection was shown by immunizing dogs with canine distemper virus (CDV) iscoms, which contained the fusion (F) protein and a minor amount of the haemagglutinin of the virus. The immunized dogs developed CDV-neutralizing antibodies but, in contrast to non-immunized dogs, did not develop viraemia or clinical signs of infection upon intranasal challenge with the virulent Snyder Hill strain of CDV. Immunization of dogs with measles virus (MV) iscoms, prepared either from affinity-purified MV F protein or from purified whole virus, resulted in partial protection against challenge with CDV. The data presented clearly show that the iscom form of antigenic presentation may be considered a serious candidate for subunit vaccines against morbillivirus infection. http://repub.eur.nl/res/pub/3342/ 1988-01-01T00:00:00Z