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PubMed1977

[Protective effect of cellular immunity in experimental Flavivirus infections].

Experiments were conducted with the tick-borne encephalitis (TE) virus; confirmation of a protective action of cellular immunity in mice was obtained. Administration of sensitized splenocytes to the animals together with the virus was accompanied with an increase of their mean survival or with the reduction of mortality in comparison with control animals given nonimmune or destroyed cells. The protective action of the effector cells was not connected with the intensification of antibody formation in the recipients. A high specificity of cellular immunity was noted in experimental flaviviral infections. The presence of common antigens in the TE and Langat viruses was revealed with the acid of cross splenocyte migration inhibition test (CSMRT). There was also revealed a difference of these viruses from the viruses of yellow fever, Dengue type 2, or Sindbis. The results of studying of the specificity of cellular immunity in the CSMRT found confirmation in experiments with adoptive transfer of splenocytes. Cross protection was caused only by splenocytes sensitized to the TE and Langat viruses.

Animals↗

PubMed2005

Protection against Leptospira interrogans sensu lato challenge by DNA immunization with the gene encoding hemolysin-associated protein 1.

The use of DNA constructs encoding leptospiral proteins is a promising new approach for vaccination against leptospirosis. In previous work we determined that immunization with hemolysis-associated protein 1 (Hap1) (LipL32) expressed by adenovirus induced significant protection against a virulent Leptospira challenge in gerbils. To avoid the use of the adenovirus vector, we checked for clinical protection against lethal challenge by DNA vaccination. A DNA vaccine expressing Hap1 was designed to enhance the direct gene transfer of this protein into gerbils. A challenge was performed 3 weeks after the last immunization with a virulent strain of serovar canicola. Our results show that the cross-protective effect with pathogenic strains of Leptospira, shared by Hap1, could be mediated by the DNA plasmid vector. This finding should facilitate the design and development of a new generation of vaccines against bacteria, particularly Leptospira interrogans sensu lato.

Animals↗

PubMed1998

[Immunobiology of bovine respiratory syncytial virus infections].

This paper describes recent findings on the immunobiology of bovine respiratory syncytial virus (BRSV) infections. The pathobiology of alveolar macrophages and BRSV, and the immunological reaction of cattle to the virus after natural or experimental infection, or vaccination, were studied. Because in severe cases BRSV infection leads to lower respiratory tract disease, replication of BRSV in alveolar macrophages was studied. Alveolar macrophages, which are important aspecific defense cells in the lower respiratory tract, exhibited a high intrinsic resistance to BRSV. Furthermore, BRSV-infected alveolar macrophages produced significantly less nitric oxide (which has a bacteriocidal effect) than uninfected macrophages. The kinetics of antibody titres against the envelope protein G were different from those of antibody titres against the envelope protein F. For example, many animals that are reinfected do not possess antibodies against the G protein. After vaccination or after natural infection, antibody titres against the F and G protein, and against epitopes on the F protein, differed markedly, and also in animals with different MHC haplotypes. These findings may be related to differences in protection. The strains of BRSV that circulate in the Netherlands belong to the subgroups A and AB. There was no evidence for differences in virulence between these subgroups. BRSV could be detected in 30% of lungs obtained from calves suffering from severe lower respiratory tract disease. Based on cross-protection studies, calves that were infected with a virus from a particular BRSV subgroup were protected against reinfection with a virus from a different subgroup. A recombinant gE-protein negative bovine herpesvirus 1 vaccine carrying a gene encoding the G protein of BRSV, and a DNA vaccine encoding the same protein afforded protection after experimental challenge of calves. This offers the possibility to develop effective multivalent (gE-negative BHV1) marker vaccines in the future.

Animals↗

PubMed2000

Evaluation of immunization with gut membrane glycoproteins of Ostertagia ostertagi against homologous challenge in calves and against Haemonchus contortus in sheep.

Peanut and ConA lectins were used as ligands to isolate glycoproteins from detergent extracts of adult Ostertagia ostertagi membranes. As judged by their profiles following SDS-PAGE, these fractions closely resembled the equivalents from Haemonchus contortus which are derived from the nematode intestinal cell microvillar membranes and which are highly protective when used as antigens. Groups of calves were immunized with the peanut and ConA binding fractions of Ostertagia, either as separate or pooled antigens mixed with QuilA as adjuvant. All calves, including controls immunized with adjuvant only, were challenged with a single dose of infective Ostertagia larvae and faecal egg counts were monitored for 5 weeks. In two experiments where the antigen fractions were pooled, moderate (30-50%), but statistically significant reductions in egg output were observed, but the number of worms was not diminished. No significant protection was observed in a third trial where groups of calves were immunized with peanut or ConA binding proteins given separately. Two further trials were conducted in sheep immunized with the same Ostertagia fractions but challenged with Haemonchus. Irrespective of whether they were administered separately or together, the Ostertagia antigens cross protected efficiently against Haemonchus reducing egg counts by between 81% and 97% and worm numbers by between 57% and 84%.

Adjuvants, Immunologic↗

PubMed1998

The oxidative stress response in Enterococcus faecalis: relationship between H2O2 tolerance and H2O2 stress proteins.

The hydrogen peroxide (H2O2) stress response in Enterococcus faecalis ATCC19433 was investigated. A 2.4 mmol l-1 H2O2 pretreatment conferred protection against a lethal concentration (45 mmol l-1) of this agent. The relatively high concentrations of H2O2 used for adaptation and challenge treatments in Ent. faecalis emphasised the strong resistance towards oxidative stress in this species. Various stresses (NaCl, heat, ethanol, acidity and alkalinity) induced weak or strong H2O2 cross-protection. This paper describes the involvement of protein synthesis in the active response to lethal dose of H2O2, in addition to the impressive enhancement of synthesis of five H2O2 stress proteins. Combined results suggest that these proteins might play an important role in the H2O2 tolerance response.

Bacterial Proteins↗

PubMed1976

Specific and Nonspecific immunity to Serratia marcescens infection.

By specific active or passive immunization, mice were protected against lethal infection with Serratia marcescens. Animals that were immunized against organisms of the challenge strain O serotype survived, whereas animals that were immunized against other serratia O serotypes did not survive. Protective sera (from convalescent partients or immunized rabbits) contained a specific complement-independent opsonin. These sera also contained passive hemagglutinating and bacterial agglutinating antibodies in high titer. The protective and complement-independent opsonizing antibodies were associated with IgG fractions of the serum, while the agglutinating antibodies were primarily associated with the IgM. Mice also survived infection with Serratia after immunization against the Re595 Salmonella minnesota mutant. However, complement-independent opsonizing antibody was not demonstrated in these cross-protective sera.

Animals↗

PubMed1989

Pathogenicity and immunogenicity of mynah pox virus in chickens and bobwhite quail.

An avian pox virus was isolated from cutaneous proliferative lesions removed from greater hill mynahs (Gracula religiosa) imported from Malaysia. Cutaneous inoculation of specific pathogen-free chickens and bobwhite quail with the mynah pox virus resulted in severe proliferative cutaneous lesions similar to those seen in the naturally infected mynah birds. Microscopically, the reaction in the chickens and quail at sites of virus inoculation was characterized by marked epithelial hyperplasia with ballooning degeneration and formation of cytoplasmic inclusion bodies. Inoculation of conjunctival and oral mucosae of chickens by applying pox virus with a cotton swab did not result in gross or microscopic lesions. In cross-protection studies, chickens and bobwhite quail immunized with either quail, fowl, pigeon, turkey, or psittacine pox vaccines were not protected from challenge with mynah pox virus. Following vaccination of quail and chickens with mynah pox virus vaccine, there was no resistance to challenge by quail, fowl, pigeon, turkey, or psittacine pox viruses. Significant protection against development of lesions following inoculation with mynah pox virus was attained only when the homologous virus was used as a vaccine.

Animals↗

PubMed1985

Experimental inoculation of cats with human coronavirus 229E and subsequent challenge with feline infectious peritonitis virus.

Minimal-disease cats exposed to live human coronavirus 229E developed homologous antibody responses that suggested little or no replication of the virus in inoculated animals. Oronasal and subcutaneous inoculation of coronavirus 229E did not elicit an antibody response by heterologous (transmissible gastroenteritis virus, canine coronavirus) neutralization or by heterologous (transmissible gastroenteritis virus) kinetics-based enzyme-linked immunosorbent assay. No clinical signs attributable to coronavirus 229E were seen in inoculated cats. Although the number of animals in each of the five experimental groups was small (n = 2), antibodies produced in response to the virus did not appear to sensitize cats to subsequent feline infectious peritonitis virus challenge, but neither did they cross-protect cats against the challenge dose.

Animals↗

PubMed2006

Characterization of the humoral immune response in dogs after vaccination against the Lyme borreliosis agent A study with five commercial vaccines using two different vaccination schedules.

Using five commercially available vaccines, groups of dogs were vaccinated against Lyme borreliosis and followed for 13 months. A modified vaccination schedule was included in the study in an attempt to induce higher and therefore longer-lasting protective antibody levels during the first year of immunization. Following vaccination antibodies were monitored using ELISA and Western blotting. Serum samples were examined either with antigen preparations derived from either Borrelia burgdorferi s. s., B. garinii or B. afzelii lysates or separately with recombinant OspA derived from the three species. Regardless of the vaccine used the third vaccination induced significantly higher antibody levels. Further analyses of the sera with homologue and heterologue detection systems showed in vitro only a minor cross-reactivity of vaccinal antibodies towards antigens derived from heterologous Borrelia species in vitro and consequently only minimal cross-protection can be expected.

Animals↗

PubMed2003

[The advent of surgical gloves].

The advent of surgical gloves had a double evolution. Evolution of the material: cecum of a sheep, cotton, silk, leather, rubber. Originally introduced to protect theatre staff's hands from corrosive solutions, subsequent use was to protect the patient from contamination by theatre staff. Many surgeons contributed to the evolution of the surgical gloves. The use of gloves was truly part of an evolutionary process than a discovery. The turning of surgical gloves is now incontestable, and their use more and more important. Surgical gloves must secure a crossing protections between surgeon and patient.

Caustics↗

PubMed1986

Comparative analysis of Haemophilus influenzae type b and Escherichia coli J5 lipopolysaccharides.

Haemophilus influenzae type b (HIB) and Escherichia coli J5 (J5) lipopolysaccharides (LPS) were examined to explore the basis of previously observed cross-protection. HIB-LPS and J5-LPS contained ketodeoxyoctonate, glucose, glucoheptose and glucosamine as common carbohydrate moieties, and laurate, myristate, beta-hydroxymyristate and palmitate as common fatty acids, although in different ratios. J5-LPS was five times more lethal than HIB-LPS for chick embryos. Weak serological cross-reactivity was observed by haemagglutination and two-dimensional immunoelectrophoresis. No significant cross-reactivity was demonstrated by enzyme-linked immunosorbent or toxicity-neutralisation assays. The cross-reactivity observed between HIB-LPS and J5-LPS was probably due to common components in the core glycolipid.

Animals↗

PubMed2004

Expression of heterologous antigens in commensal Neisseria spp.: preservation of conformational epitopes with vaccine potential.

Commensal neisseriae share with Neisseria meningitidis (meningococcus) a tendency towards overproduction of the bacterial outer envelope, leading to the formation and release during growth of outer membrane vesicles (OMVs). OMVs from both meningococci and commensal neisseriae have shown promise as vaccines to protect against meningococcal disease. We report here the successful expression at high levels of heterologous proteins in commensal neisseriae and the display, in its native conformation, of one meningococcal outer membrane protein vaccine candidate, NspA, in OMVs prepared from such a recombinant Neisseria flavescens strain. These NspA-containing OMVs conferred protection against otherwise lethal intraperitoneal challenge of mice with N. meningitidis serogroup B, and sera raised against them mediated opsonophagocytosis of meningococcal strains expressing this antigen. This development promises to facilitate the design of novel vaccines containing membrane protein antigens that are otherwise difficult to present in native conformation that provide cross-protective efficacy in the prevention of meningococcal disease.

Animals↗

PubMed2005

Genetic and physiological analysis of the major OxyR-regulated katA from Xanthomonas campestris pv. phaseoli.

katA encodes the major catalase that accounts for 90 % of the total catalase activity present in Xanthomonas campestris pv. phaseoli. katA is located upstream of an ORF designated ankA encoding a cytoplasmic membrane protein homologous to eukaryotic ankyrin. Transcriptional analysis of katA and ankA identified two katA transcripts: a major monocistronic katA transcript and a minor bicistronic katA-ankA transcript. KatA expression was induced in the presence of various oxidants including H2O2, organic hydroperoxides and the superoxide-generating agent menadione, in an OxyR-dependent manner. Analysis of the katA promoter region showed a putative OxyR binding site located upstream of an Escherichia coli-like sigma70 -35 region that is likely to be responsible for transcription activation in response to oxidant treatment. Gel mobility shift experiments confirmed that purified OxyR specifically binds to the katA promoter. A katA mutant was highly sensitive to H2O2 during both the exponential and stationary phases of growth. This phenotype could be complemented by functional katA, confirming the essential role of the gene in protecting X. campestris from H2O2 toxicity. Unexpectedly, inactivation of ankA also significantly reduced resistance to H2O2 and the phenotype could be complemented by plasmid-borne expression of ankA. Physiological analyses showed that katA plays an important role in, but is not solely responsible for, both the adaptive and menadione-induced cross-protective responses to H2O2 killing in X. campestris.

Ankyrins↗

PubMed1992

Prevention of HIV-2 and SIVSM infection in cynomolgus monkeys by active or passive immunization.

We have established experimental infection with HIV-2 and SIVsm in cynomolgus monkeys and successfully used these models for vaccine experiments. Protection against homologous HIV-2 infection was demonstrated in two of two monkeys immunized with a Triton-X100-treated whole HIV-2SBL-6669 vaccine in incomplete Freund's adjuvant and in 2 of 4 monkeys immunized with a formalin-inactivated whole HIV-2 vaccine in RIBI adjuvant. Monkeys preinfected with a live poorly replicating HIV-2 strain were shown to develop cross-protection against SIV-induced disease. We have shown also that HIV-2 and SIVsm infection in cynomolgus monkeys can be prevented by passive immunization. These results raise hope for effective immunization against HIV infections in humans.

AIDS Vaccines↗

PubMed2005

Induction of strain-transcending immunity against Plasmodium chabaudi adami malaria with a multiepitope DNA vaccine.

A major goal of current malaria vaccine programs is to develop multivalent vaccines that will protect humans against the many heterologous malaria strains that circulate in endemic areas. We describe a multiepitope DNA vaccine, derived from a genomic Plasmodium chabaudi adami DS DNA expression library of 30,000 plasmids, which induces strain-transcending immunity in mice against challenge with P. c. adami DK. Segregation of this library and DNA sequence analysis identified vaccine subpools encoding open reading frames (ORFs)/peptides of >9 amino acids [aa] (the V9+ pool, 303 plasmids) and >50 aa (V50+ pool, 56 plasmids), respectively. The V9+ and V50+ plasmid vaccine subpools significantly cross-protected mice against heterologous P. c. adami DK challenge, and protection correlated with the induction of both specific gamma interferon production by splenic cells and opsonizing antibodies. Bioinformatic analysis showed that 22 of the V50+ ORFs were polypeptides conserved among three or more Plasmodium spp., 13 of which are predicted hypothetical proteins. Twenty-nine of these ORFs are orthologues of predicted Plasmodium falciparum sequences known to be expressed in the blood stage, suggesting that this vaccine pool encodes multiple blood-stage antigens. The results have implications for malaria vaccine design by providing proof-of-principle that significant strain-transcending immunity can be induced using multiepitope blood-stage DNA vaccines and suggest that both cellular responses and opsonizing antibodies are necessary for optimal protection against P. c. adami.

Animals↗

PubMed1998

The inactivated Cowdria ruminantium vaccine for heartwater protects against heterologous strains and against laboratory and field tick challenge.

We previously described that an inactivated vaccine against heartwater prepared from Cowdria ruminantium (Crystal Springs strain) organisms and administered in complete Freund's adjuvant (cFA) protected sheep against homologous needle challenge. Further studies, described herein, demonstrated that this vaccine protected 100% of sheep against death on challenge with laboratory-infected ticks and with field ticks in a heartwater endemic farm, whereas a mortality rate of 44% and 62%, respectively, was recorded in the control sheep. Subsequently, the Mbizi strain of C. ruminantium was incorporated into the vaccine because of its wider cross-protective capacity, and trial data suggested that protection may be achieved against challenge with diverse geographical strains using this strain. The efficacy of five adjuvants with acceptable safety was compared with that of cFA. Against a homologous intravenous challenge, highest survival rates were observed in sheep vaccinated with inactivated C. ruminantium in either cFA, Montanide ISA 50 or Quil A. The vaccine prepared in Montanide ISA 50 protected six of seven sheep against natural challenge from field ticks on a farm in Zimbabwe where heartwater is endemic, whereas six of seven control sheep died (P = 0.029). These data support optimization of the vaccine prepared in Montanide ISA 50, followed by evaluation of its efficacy in all target domestic ruminant species and in other geographical regions where heartwater constrains livestock production.

Animals↗

PubMed2000

The immunogenicity and pathogenicity of Pasteurella multocida isolated from poultry in Indonesia.

Of 13 field isolates of Pasteurella from chickens and ducks in Indonesia, 10 were confirmed as P. multocida subspecies multocida, one as P. multocida subspecies gallicida and one as P. multocida subspecies septica. Nine were capsular Type A four were Serotype 1, one was Serotype 4, one was Serotype 11, one was Serotypes 4,12, and the remaining six were untypable. Five isolates were pathogenic for mice and two were pathogenic for chickens. Both a trivalent vaccine which included local field isolates and an imported commercial vaccine, were efficacious in layer chickens against challenge with virulent reference and local field strains. Though not statistically significant, the protection provided by the trivalent vaccine against virulent field isolate challenge was slightly better and could provide an improvement over the currently used imported vaccine although further field trials are required. A bacterin vaccine produced from a Serotype 1 field isolate grown in the allantoic sac of embryonated chicken eggs provided chickens with good cross protection against heterologous serotype challenge.

Animals↗

PubMed1993

Immune sera to individual Borrelia burgdorferi isolates or recombinant OspA thereof protect SCID mice against infection with homologous strains but only partially or not at all against those of different OspA/OspB genotype.

The outer surface proteins OspA and OspB of Borrelia burgdorferi have recently been demonstrated to be major target proteins for protective antibodies in mice against infection with the homologous spirochaetal strain. However, it has become clear from a variety of studies that B. burgdorferi isolates of different geographical origin and/or sources are heterogeneous and that they can be divided into at least six subgroups according to their distinct OspA/OspB genotypes. In order to analyse cross-protection between these subgroups we have now generated immune sera to various isolates of B. burgdorferi with different OspA/OspB genotypes. We show that passive immunization with antisera specific for whole spirochaetes or recombinant OspA of one spirochaetal isolate protects severe combined immunodeficiency mice against infection with strains of the corresponding OspA/OspB genotype but only partially or not at all against infection with isolates expressing distinct OspA/OspB genotypes. The incomplete protection mediated by individual antisera against independent isolates of B. burgdorferi suggests that an effective subunit vaccine against Lyme disease should consist of a mixture of OspA structures covering the heterogeneity of this protein within the species B. burgdorferi.

Animals↗