RESUMEN
dsRNA-dependent protein kinase R (PKR) is a key factor of innate immunity. It is involved in translation inhibition, apoptosis, and enhancement of the proinflammatory and IFN responses. However, how these antiviral functions are conserved during evolution remains largely unknown. Overexpression and knockout studies in a Chinook salmon (Oncorhynchus tshawytscha) cell line were conducted to assess the role of salmonid PKR in the antiviral response. Three distinct mRNA isoforms from a unique pkr gene, named pkr-fl (full length), pkr-ml (medium length) and pkr-sl (short length), were cloned and a pkr-/- clonal fish cell line was developed using CRISPR/Cas9 genome editing. PKR-FL includes an N-terminal dsRNA-binding domain and a C-terminal kinase domain, whereas PKR-ML and PKR-SL display a truncated or absent kinase domain, respectively. PKR-FL is induced during IFNA2 stimulation but not during viral hemorrhagic septicemia virus (VHSV) infection. Overexpression experiments showed that only PKR-FL possesses antiviral functions, including activation of apoptosis and inhibition of de novo protein synthesis. Knockout experiments confirmed that PKR is involved in apoptosis activation during the late stage of VHSV infection. Endogenous PKR also plays a critical role in translation inhibition upon poly(I:C) transfection after IFNA2 treatment. It is, however, not involved in translational arrest during VHSV infection. Extra- and intracellular titrations showed that endogenous PKR does not directly inhibit viral replication but apparently favors virion release into the supernatant, likely by triggering late apoptosis. Altogether, our data confirm that salmonid PKR has conserved molecular functions that VHSV appears to bypass with subversion strategies.
Asunto(s)
Apoptosis , Biosíntesis de Proteínas , Salmón , eIF-2 Quinasa , Animales , Apoptosis/inmunología , eIF-2 Quinasa/metabolismo , eIF-2 Quinasa/genética , Salmón/inmunología , Línea Celular , Biosíntesis de Proteínas/inmunología , Inmunidad Innata , Novirhabdovirus/fisiología , Novirhabdovirus/inmunología , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Proteínas de Peces/metabolismo , ARN Bicatenario/inmunología , Enfermedades de los Peces/inmunología , Sistemas CRISPR-CasRESUMEN
BACKGROUND: Viperin, also known as radical S-adenosyl-methionine domain containing protein 2 (RSAD2), is an interferon-inducible protein that is involved in the innate immune response against a wide array of viruses. In mammals, Viperin exerts its antiviral function through enzymatic conversion of cytidine triphosphate (CTP) into its antiviral analog ddhCTP as well as through interactions with host proteins involved in innate immune signaling and in metabolic pathways exploited by viruses during their life cycle. However, how Viperin modulates the antiviral response in fish remains largely unknown. RESULTS: For this purpose, we developed a fathead minnow (Pimephales promelas) clonal cell line in which the unique viperin gene has been knocked out by CRISPR/Cas9 genome-editing. In order to decipher the contribution of fish Viperin to the antiviral response and its regulatory role beyond the scope of the innate immune response, we performed a comparative RNA-seq analysis of viperin-/- and wildtype cell lines upon stimulation with recombinant fathead minnow type I interferon. CONCLUSIONS: Our results revealed that Viperin does not exert positive feedback on the canonical type I IFN but acts as a negative regulator of the inflammatory response by downregulating specific pro-inflammatory genes and upregulating repressors of the NF-κB pathway. It also appeared to play a role in regulating metabolic processes, including one carbon metabolism, bone formation, extracellular matrix organization and cell adhesion.
Asunto(s)
Cyprinidae , Inflamación , Animales , Cyprinidae/metabolismo , Cyprinidae/genética , Inflamación/metabolismo , Inflamación/genética , Inmunidad Innata , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Línea Celular , Sistemas CRISPR-Cas , Interferón Tipo I/metabolismo , Edición Génica , Regulación de la Expresión GénicaRESUMEN
OBJECTIVE: To evaluate canarypox-vectored equine influenza virus (EIV) vaccines expressing hemagglutinins of A/equine/Kentucky/94 (vCP1529) and A2/equine/Ohio /03 (vCP2242) for induction of antibody responses against canine influenza virus (CIV) in dogs. ANIMALS: 35 dogs. PROCEDURES: Dogs were randomly allocated into 4 groups; group 1 (n = 8) and group 2 (9) were inoculated SC on days 0 and 28 with 1.0 mL (approx 10(5.7) TCID(50)) of vCP1529 and vCP2242, respectively. Dogs in group 3 (n = 9) were inoculated twice with 0.25 mL (approx 10(5.7) TCID(50)) of vCP2242 via the transdermal route. The 9 dogs of group 4 were control animals. All dogs were examined for adverse reactions. Sera, collected on days -1, 7, 13, 21, 28, 35, and 42, were tested by hemagglutination inhibition (HI) and virus neutralization (VN) assays for antibodies against CIV antigens A/Canine/FL/43/04-PR and A/Canine/NY/115809/05, respectively. RESULTS: Inoculations were tolerated well. The HI and VN antibodies were detected by 7 days after primary inoculation. Most dogs of groups 1 and 2 and all dogs of group 3 had detectable antibodies by 14 days after initial inoculation. The second inoculation induced an anamnestic response, yielding geometric mean HI titers of 139, 276, and 1,505 and VN titers of 335, 937, and 3,288 by day 42 (14 days after booster inoculation) in groups 1, 2, and 3, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Canarypox-vectored EIV vaccines induce biologically important antibodies and may substantially impact CIV transmission within a community and be of great value in protecting dogs against CIV-induced disease.
Asunto(s)
Virus de la Viruela de los Canarios/genética , Enfermedades de los Perros/inmunología , Enfermedades de los Perros/virología , Subtipo H3N8 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Infecciones por Orthomyxoviridae/veterinaria , Animales , Anticuerpos Antivirales/inmunología , Perros , Femenino , Masculino , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/virología , Vacunas Sintéticas/inmunologíaRESUMEN
OBJECTIVE: To determine onset and duration of immunity provided by a 2- or 3-dose series of a new canarypox-vectored recombinant vaccine for equine influenza virus (rCP-EIV vaccine) expressing the hemagglutinin genes of influenza H3N8 virus strains A/eq/Kentucky/94 and A/eq/Newmarket/2/93 in ponies. ANIMALS: Forty-nine 1- to 3-year-old male Welsh Mountain Ponies that were seronegative for equine influenza virus. PROCEDURES: Vaccinated and control ponies were challenged with aerosolized influenza virus A/eq/Sussex/89 (H3N8), representative of the Eurasian lineage of circulating influenza viruses. In trial 1, control ponies and ponies that received rCP-EIV vaccine were challenged 2 weeks after completion of the 2-dose primary vaccination program. In trial 2, ponies were challenged 5 months after 2 doses of rCP-EIV vaccine or 1 year after the first boosting dose of rCP-EIV vaccine, administered 5 months after completion of the primary vaccination program. After challenge, ponies were observed daily for clinical signs of influenza and nasal swab specimens were taken to monitor virus excretion. RESULTS: The challenge reliably produced severe clinical signs consistent with influenza infection in the control ponies, and virus was shed for up to 7 days. The vaccination protocol provided clinical and virologic protection to vaccinates at 2 weeks and 5 months after completion of the primary vaccination program and at 12 months after the first booster. CONCLUSION AND CLINICAL RELEVANCE: The rCP-EIV vaccine provided protection of ponies to viral challenge. Of particular importance was the protection at 5 months after the second dose, indicating that this vaccine closes an immunity gap between the second and third vaccination.
Asunto(s)
Virus de la Viruela de los Canarios/genética , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Enfermedades de los Caballos/prevención & control , Enfermedades de los Caballos/virología , Subtipo H3N8 del Virus de la Influenza A/inmunología , Infecciones por Orthomyxoviridae/veterinaria , Animales , Anticuerpos Antivirales/sangre , Regulación Viral de la Expresión Génica , Enfermedades de los Caballos/inmunología , Caballos , Subtipo H3N8 del Virus de la Influenza A/fisiología , Masculino , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Infecciones por Orthomyxoviridae/virología , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunologíaRESUMEN
Control and glucocorticoid-treated dogs were infected with West Nile virus (WNV) through the bites of infected mosquitoes to study the effect of a commonly used immunomodulator on the magnitude and duration of viremia and on development of clinical disease. All dogs became viremic after challenge. The peak viremia and integrated magnitude of viremia were approximately 40 and 50 times higher, respectively, in the five dogs treated with methyl-prednisolone for 1 month compared with untreated dogs. None of the five control or treated dogs developed signs of clinical disease, nor was histopathologic evidence of neuroinvasion observed in any case. Neutralizing antibodies to WNV were produced in all dogs, with no apparent effect of glucocorticoid treatment. Considering the dramatic effect of glucocorticoid treatment on magnitude of viremia, it is likely that this therapy had suppressive effects on some aspect of innate immunity or T cell function.
Asunto(s)
Enfermedades de los Perros/virología , Glucocorticoides/administración & dosificación , Metilprednisolona/administración & dosificación , Fiebre del Nilo Occidental/veterinaria , Virus del Nilo Occidental/inmunología , Animales , Anticuerpos Antivirales/biosíntesis , Enfermedades de los Perros/sangre , Perros , Femenino , Glucocorticoides/efectos adversos , Inyecciones Intramusculares/veterinaria , Metilprednisolona/efectos adversos , Resultado del Tratamiento , Viremia/veterinaria , Fiebre del Nilo Occidental/virologíaRESUMEN
Efficacy of the Recombitek Equine West Nile Virus (WNV) vaccine was evaluated against a WNV intrathecal challenge model that results in WNV-induced clinical disease. Ten vaccinated (twice at days 0 and 35) and 10 control horses were challenged 2 weeks after administration of the second vaccine with a virulent WNV by intrathecal administration. After the challenge, eight of 10 controls developed clinical signs of encephalomyelitis whereas one vaccinate exhibited muscle fasciculation only once. Nine controls and one vaccinate developed a fever. Histopathology revealed mild to moderate nonsuppurative encephalitis in eight controls and one vaccinate. None of the vaccinates and all of the controls developed WNV viremia after challenge. All vaccinated horses developed antibodies to WNV after vaccination. These and results of previous studies demonstrate efficacy of the Recombitek WNV vaccine against WNV-induced clinical disease and natural challenge with WNV-infected mosquitoes.
Asunto(s)
Culicidae/virología , Enfermedades de los Caballos/prevención & control , Fiebre del Nilo Occidental/veterinaria , Vacunas contra el Virus del Nilo Occidental/inmunología , Virus del Nilo Occidental/inmunología , Animales , Anticuerpos Antivirales/biosíntesis , Anticuerpos Antivirales/sangre , Virus de la Viruela de los Canarios/inmunología , Femenino , Caballos , Masculino , Distribución Aleatoria , Resultado del Tratamiento , Viremia/veterinaria , Fiebre del Nilo Occidental/prevención & control , Virus del Nilo Occidental/patogenicidadRESUMEN
OBJECTIVE: To determine the onset of immunity after IM administration of a single dose of a recombinant canarypox virus vaccine against West Nile virus (WNV) in horses in a blind challenge trial. ANIMALS: 20 mixed-breed horses. PROCEDURE: Horses with no prior exposure to WNV were randomly assigned to 1 of 2 groups (10 horses/group). In 1 group, a recombinant canarypox virus vaccine against WNV was administered to each horse once (day 0). The other 10 control horses were untreated. On day 26, 9 treated and 10 control horses were challenged via the bites of mosquitoes (Aedes albopictus) infected with WNV. Clinical responses and WNV isolation were monitored for 14 days after challenge exposure; antibody responses against WNV after administration of the vaccine and challenge were also assessed in both groups. RESULTS: Following challenge via WNV-infected mosquitoes, 1 of 9 treated horses developed viremia. In contrast, 8 of 10 control horses developed viremia after challenge exposure to WNV-infected mosquitoes. All horses seroconverted after WNV challenge; compared with control horses, antibody responses in the horses that received the vaccine were detected earlier. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, a single dose of the recombinant canarypox virus-WNV vaccine appears to provide early protection against development of viremia after challenge with WNV-infected mosquitoes, even in the absence of measurable antibody titers in some horses. This vaccine may provide veterinarians with an important tool in controlling WNV infection during a natural outbreak or under conditions in which a rapid onset of protection is required.
Asunto(s)
Enfermedades de los Caballos/inmunología , Enfermedades de los Caballos/prevención & control , Enfermedades de los Caballos/virología , Vacunas Virales/inmunología , Fiebre del Nilo Occidental/veterinaria , Virus del Nilo Occidental/inmunología , Aedes/virología , Análisis de Varianza , Animales , Anticuerpos Antivirales/inmunología , Virus de la Viruela de los Canarios/inmunología , CaballosRESUMEN
Dogs account for the majority of human exposures and deaths due to rabies virus (RABV) worldwide. In this report, we show that a replication-deficient RABV-based vaccine in which the matrix gene is deleted (RABV-ΔM) is safe and induces rapid and potent VNA titers after a single inoculation in dogs. Average VNA titers peaked at 3.02 or 5.11 international units (IU/ml) by 14 days post-immunization with a single dose of 10(6) or 10(7) focus forming units (ffu), respectively, of RABV-ΔM. By day 70 post immunization, all dogs immunized with either dose of vaccine showed VNA titers >0.5IU/ml, the level indicative of a satisfactory immunization. Importantly, no systemic or local reactions were noted in any dog immunized with RABV-ΔM. The elimination of dog rabies through mass vaccination is hindered by limited resources, requirement for repeat vaccinations often for the life of a dog, and in some parts of the world, inferior vaccine quality. Our preliminary safety and immunogenicity data in dogs suggest that RABV-ΔM might complement currently used inactivated RABV-based vaccines in vaccination campaigns by helping to obtain 100% response in vaccinated dogs, thereby increasing overall vaccination coverage.
Asunto(s)
Anticuerpos Antivirales/sangre , Enfermedades de los Perros/prevención & control , Vacunas Antirrábicas/inmunología , Rabia/veterinaria , Animales , Anticuerpos Neutralizantes/sangre , Enfermedades de los Perros/virología , Perros , Femenino , Eliminación de Gen , Masculino , Rabia/prevención & control , Vacunas Antirrábicas/genética , Virus de la Rabia/genética , Proteínas de la Matriz Viral/genéticaRESUMEN
West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the USA, Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are licensed in the USA for use in geese. This study reports the development of a domestic goose vaccine efficacy model, based on utilizing multiple parameters to determine protection. To test the model, 47 geese were divided in two experiments, testing five different vaccine groups and two sham groups (challenged and unchallenged). Based on the broad range of results for individual metrics between the Challenged-Sham and Unchallenged-Sham groups, the best parameters to measure protection were Clinical Pathogenicity Index (CPI), plasma virus positive geese on days 1-4 post-inoculation and plasma virus titers, and brain histological lesion rates and severity scores. Compared to the Challenged-Sham group, the fowlpox virus vectored vaccine with inserts of WNV prM and E proteins (vFP2000) provided the best protection with significant differences in all five metrics, followed by the canarypox virus vectored vaccine with inserts of WNV prM and E proteins (vCP2018) with four metrics of protection, recombinant vCP2017 with three metrics and WNV E protein with one. These data indicate that domestic geese can be used in an efficacy model for vaccine protection studies using clinical, plasma virological and brain histopathological parameters to evaluate protection against WNV challenge.
Asunto(s)
Gansos , Vacunación/métodos , Fiebre del Nilo Occidental/prevención & control , Vacunas contra el Virus del Nilo Occidental/administración & dosificación , Vacunas contra el Virus del Nilo Occidental/inmunología , Animales , Encéfalo/patología , Encéfalo/virología , Modelos Animales de Enfermedad , Histocitoquímica , Carga Viral , Viremia/prevención & control , Fiebre del Nilo Occidental/patología , Fiebre del Nilo Occidental/virologíaRESUMEN
Equine influenza virus is a leading cause of respiratory disease in the horse population; however, the susceptibility of old horses to EIV infection remains unknown. While advanced age in horses (>20 years) is associated with age-related changes in immune function, there are no specific recommendations regarding the vaccination of older horses even though a well-characterized effect of aging is a reduced antibody response to standard vaccination. Therefore, we evaluated the immunological and physiological response of aged horses to a live non-replicating canarypox-vectored EIV vaccine and subsequent challenge infection. Vaccination of the aged horses induced EIV-specific IgGb and HI antibodies. No specific increase in cell-mediated immune (CMI) response was induced by the vaccine as determined by EIV-specific lymphoproliferation and the detection of EIV-specific IFNγ(+) CD5(+)T cells, IFNγ, IL-2, IL-4 and IL-13 mRNA expression. Non-vaccinated aged horses exhibited clinical signs of the disease (coughing, nasal discharge, dyspnea, depression, anorexia) as well as increased rectal temperature and viral shedding following challenge. Concomitant with the febrile episodes, we also observed increased production of pro-inflammatory cytokine mRNA production in vivo using RT-PCR. Naïve horses were included in this study for vaccine and challenge controls only. As expected, the canarypox-vectored EIV vaccine stimulated significant CMI and humoral immune responses and provided significant protection against clinical signs of disease and reduced virus shedding in naive horses. Here, we show that aged horses remain susceptible to infection with equine influenza virus despite the presence of circulating antibodies and CMI responses to EIV and vaccination with a canarypox-vectored EIV vaccine provides protection from clinical disease.
Asunto(s)
Envejecimiento/inmunología , Virus de la Viruela de los Canarios/inmunología , Enfermedades de los Caballos/prevención & control , Subtipo H3N8 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Infecciones por Orthomyxoviridae/inmunología , Animales , Caballos , Inmunidad Celular , Inmunidad Humoral , Vacunas Sintéticas/inmunologíaRESUMEN
Equine influenza virus remains an important problem in horses despite extensive use of vaccination. Efficacy of equine influenza vaccination depends on the onset and duration of protective immunity, and appropriate strain specificity of the immune response. This study was designed to test the protective immunity resulting from vaccination with the North American commercial ALVAC equine influenza vaccine (RECOMBITEK Influenza, Merial, USA)(1) against challenge with American lineage influenza viruses. In experiment 1, 12 ponies were vaccinated twice, at a 35 day interval, using the ALVAC-influenza vaccine expressing the HA genes of influenza A/eq/Newmarket/2/93 and A/eq/Kentucky/94 (H3N8), and 11 ponies served as unvaccinated controls. Six months after the second vaccination, all ponies were challenged with A/eq/Kentucky/91. In experiment 2, 10 ponies received one dose of the ALVAC-influenza vaccine, 10 ponies served as unvaccinated controls, and all ponies were challenge infected with A/equine/Ohio/03, 14 days after vaccination. Parameters studied included serological responses, and clinical disease and nasal viral shedding following challenge infection. In experiment 1, following the two-dose regimen, vaccinated ponies generated high titered anti-influenza virus IgGa and IgGb antibody responses to vaccination and demonstrated statistically significant clinical and virological protection to challenge infection compared to controls. Infection with A/eq/Kentucky/91 produced unusually severe signs in ponies in the control group, requiring therapy with NSAID's and antibiotics, and leading to the euthanasia of one pony. In experiment 2 following the one-dose regimen, vaccinates generated IgGa responses pre-challenge, and anamnestic IgGa and IgGb responses after challenge. Vaccinates demonstrated statistically significant clinical and virological protection to challenge infection compared to controls. The results of this study clearly demonstrate the early onset, and 6-month duration of protective immunity resulting from ALVAC-influenza vaccination against challenge with American lineage equine influenza viruses.
Asunto(s)
Enfermedades de los Caballos/prevención & control , Subtipo H3N8 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/uso terapéutico , Infecciones por Orthomyxoviridae/veterinaria , Animales , Anticuerpos Antivirales/sangre , Formación de Anticuerpos/inmunología , Virus de la Viruela de los Canarios , Enfermedades de los Caballos/inmunología , Enfermedades de los Caballos/virología , Caballos/inmunología , Vacunas contra la Influenza/inmunología , Masculino , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Vacunas Sintéticas/inmunología , Vacunas Sintéticas/uso terapéutico , Esparcimiento de Virus/inmunologíaRESUMEN
We describe the development and preliminary characterization of a recombinant canarypox virus vectored (ALVAC) vaccine for protective immunization of equids against African horse sickness virus (AHSV) infection. Horses (n=8) immunized with either of two concentrations of recombinant canarypox virus vector (ALVAC-AHSV) co-expressing synthetic genes encoding the outer capsid proteins (VP2 and VP5) of AHSV serotype 4 (AHSV-4) developed variable titres (<10-80) of virus-specific neutralizing antibodies and were completely resistant to challenge infection with a virulent strain of AHSV-4. In contrast, a horse immunized with a commercial recombinant canarypox virus vectored vaccine expressing the haemagglutinin genes of two equine influenza H3N8 viruses was seronegative to AHSV and following infection with virulent AHSV-4 developed pyrexia, thrombocytopenia and marked oedema of the supraorbital fossae typical of the "dikkop" or cardiac form of African horse sickness. AHSV was detected by virus isolation and quantitative reverse transcriptase polymerase chain reaction in the blood of the control horse from 8 days onwards after challenge infection whereas AHSV was not detected at any time in the blood of the ALVAC-AHSV vaccinated horses. The control horse seroconverted to AHSV by 2 weeks after challenge infection as determined by both virus neutralization and ELISA assays, whereas six of eight of the ALVAC-AHSV vaccinated horses did not seroconvert by either assay following challenge infection with virulent AHSV-4. These data confirm that the ALVAC-AHSV vaccine will be useful for the protective immunization of equids against African horse sickness, and avoids many of the problems inherent to live-attenuated AHSV vaccines.
Asunto(s)
Enfermedad Equina Africana/prevención & control , Proteínas de la Cápside/inmunología , Caballos/inmunología , Vacunas Virales/inmunología , Enfermedad Equina Africana/inmunología , Virus de la Enfermedad Equina Africana/inmunología , Virus de la Enfermedad Equina Africana/aislamiento & purificación , Animales , Anticuerpos Antivirales/sangre , Virus de la Viruela de los Canarios/inmunología , Células Cultivadas , Cricetinae , Femenino , Masculino , Vacunas Atenuadas/inmunologíaRESUMEN
The canarypox vaccine vector (ALVAC) technology has been used to develop and license several vaccines for companion animals and horses in the European Union and USA. ALVAC is a ubiquitous vector with high biosafety since it is non-replicative in mammalians, is genetically and physically stable, and able to induce both humoral and cell-mediated immune responses against the expressed transgene product. Specific rules apply for the development and registration of recombinant vector vaccines. The biology of the vector as well as the recombinant virus must be thoroughly documented to allow the risk assessment of its use in the target species. In particular, its safety for the host and the environment must be extensively demonstrated before field trials can be authorized.
Asunto(s)
Virus de la Viruela de los Canarios/genética , Aprobación de Drogas , Vectores Genéticos/genética , Vacunas Virales/uso terapéutico , Animales , Vacunas Sintéticas/efectos adversos , Vacunas Sintéticas/genética , Vacunas Sintéticas/uso terapéutico , Vacunas Virales/efectos adversos , Vacunas Virales/genéticaRESUMEN
The increasing international movement of horses combined with the relaxation of veterinary regulations has resulted in an increased incidence of equine infectious diseases. Vaccination, along with management measures, has become the primary method for the effective control of these diseases. Traditionally modified live and inactivated vaccines have been used and these vaccines have proven to be very successful in preventing disease. However, there are a number of equine infectious diseases for which conventional technology has shown its limitations. The advent of recombinant technology has stimulated the development of second generation vaccines, including gene deleted mutants, live vectored vaccines and DNA vaccines. These vaccines have in common that protective antigens are endogenously processed and presented along the molecules of the MHC I and MHC II complex, resulting in the stimulation of both humoral and cell-mediated immune responses similar to natural infection. The present paper provides a review of the vaccines being employed today against the most important equine viral diseases followed by a summary of new developments that are expected to bring improved vaccines to the market in the foreseeable future.
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Enfermedades de los Caballos/prevención & control , Enfermedades de los Caballos/virología , Vacunación/veterinaria , Vacunas Virales , Animales , Arteritis/veterinaria , Encefalomielitis Equina , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/inmunología , Caballos , Infecciones por Orthomyxoviridae/veterinaria , Fiebre del Nilo Occidental/veterinariaRESUMEN
In order for DNA vaccines to become a practical alternative to conventional vaccines their ability to induce antibody responses in large mammals needs to be improved. We used DNA vaccination against rabies in the horse as a model to test the potential of two different strategies to enhance antibody responses in a large mammalian species. The administration of the DNA vaccine in the presence of aluminum phosphate improved both the onset and the intensity of serological responses but was not potent enough to achieve seroconversion in all vaccinated ponies. However, when the DNA vaccine was formulated with the cationic lipid DMRIE-DOPE instead of aluminum phosphate, a very strong impact on both onset and intensity of serological responses was observed. This latter strategy ensured excellent seroconversion in all vaccinated ponies after a primary course of two injections, demonstrating a clear improvement of the homogeneity of the induced responses. These data indicate that rabies DNA vaccination is feasible in horses and further suggests that properly formulated DNA vaccines can generate immune responses in large veterinary species at a level comparable to the responses achieved with conventional vaccines.
Asunto(s)
Anticuerpos Antivirales/biosíntesis , Antígenos Virales , Caballos/inmunología , Vacunas Antirrábicas/inmunología , Adyuvantes Inmunológicos , Compuestos de Aluminio , Animales , Anticuerpos Antivirales/análisis , ADN Complementario/inmunología , ADN Complementario/aislamiento & purificación , Relación Dosis-Respuesta Inmunológica , Glicoproteínas/inmunología , Lípidos , Fosfatos , Compuestos de Amonio Cuaternario , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vacunas de ADN/inmunología , Proteínas del Envoltorio Viral/inmunologíaRESUMEN
We assessed whether the formulation of a DNA vaccine expressing the canine distemper virus (CDV) hemagglutinin (HA) and fusion (F) immunogens with the cationic lipid DMRIE-DOPE could induce serological responses and protection against a severe CDV challenge in the dog. Although clear protection was observed in dogs vaccinated with formulated plasmids only limited CDV specific antibody titers were observed in protected dogs before challenge, suggesting that protection could be explained by cell-mediated immunity and/or by a strong antibody-based memory response (priming) triggered by the infectious challenge. The high level of protection achieved in this study, demonstrated that formulated DNA CDV vaccines can generate in dogs a level a protection comparable to conventional CDV vaccines.
Asunto(s)
Virus del Moquillo Canino/inmunología , Moquillo/prevención & control , Vacunación/veterinaria , Vacunas de ADN , Vacunas Virales , Adyuvantes Inmunológicos , Animales , Anticuerpos Antivirales , ADN Complementario , Perros , Vectores Genéticos/genética , Vectores Genéticos/inmunología , Inmunidad Celular , Memoria Inmunológica , Lípidos , Pruebas de Neutralización , Fosfatidiletanolaminas , Compuestos de Amonio Cuaternario , Organismos Libres de Patógenos Específicos , Vacunas de ADN/inmunología , Vacunas Virales/inmunologíaRESUMEN
None of the currently available distemper vaccines provides a satisfactory solution for the immunization of very young carnivores in the face of maternal-derived immunity. Since mucosal immunization with replication-competent adenovirus-based vaccines has been proven effective in the face of passive immunity against the vector, it has the potential to provide a solution for the vaccination of young puppies born to canine distemper virus (CDV)-immune dams. We report the engineering and the characterization of two replication-competent canine adenovirus type 2 (CAV2)-based vaccines expressing, respectively, the CDV hemagglutinin (HA) and fusion (F) antigens. We first demonstrated that the intranasal vaccination with a mixture of both recombinant CAV2s provides an excellent level of protection in seronegative puppies, confirming the value of replication-competent adenovirus-based vectors for mucosal vaccination. In contrast, intranasal immunization with the same vaccine of puppies born to CDV- and CAV2-immune dams, failed to activate specific and protective immune responses. We hypothesized that an active CAV2 infection occurred while puppies were in close contact with the vaccinated dams in the breeding units and that the resulting active mucosal immunity interfered with the intranasal administration of CAV2-based CDV vaccine. However, when puppies born to CDV- and CAV2-immune dams were vaccinated subcutaneously with the CAV2-based CDV vaccine, significant seroconversion and solid protective immunity were triggered despite pre-existing systemic immunity to the vector. This latter result is surprising and suggests that subcutaneous vaccination with a replication-competent recombinant CAV2 may be an efficient strategy to overcome both passive and active adenovirus specific immunity in the dog. From a practical point of view, this could pave the way for an original strategy to vaccinate young puppies in the face of maternal-derived immunity.