Respuesta inmune y alergia a vacunas / Immune response and allergies to vaccines

Las vacunas son altamente efectivas en prevenir enfermedades infecciosas a través del desarrollo en el individuo de una respuesta inmune protectora, sin desarrollar la enfermedad. Los distintos tipos de vacunas producen diferentes tipos de respuestas inmunes y variadas estrategias se han desarrollado para mejorar esta respuesta. El sistema inmune sufre cambios con la edad y esta inmunosenecencia altera la capacidad de responder frente a ellas. Por otro lado, si bien el sistema inmune puede reconocer elementos presentes en las vacunas y montar respuestas de hipersensibilidad ante ellos, las alergias a las vacunas son raras, teniendo que distinguirlas adecuadamente de otro tipo de reacciones. En caso que un paciente presente una reacción compatible con alergia, es importante conocer todos los componentes de la vacuna para realizar un estudio adecuado.

Vaccines are highly effective in preventing infectious diseases through the development in the individual a protective immune response, without developing the disease. Different types of vaccines produce different types of immune responses, and varied strategies have been developed to improve this response. The immune system undergoes changes with age, and this inmunosenescence alters the ability to respond to them. On the other hand, although the immune system can recognize elements present in vaccines and establish hypersensitivity responses to them, vaccine allergies are rare, having to properly distinguish them from other types of reactions. In the event that a patient has an allergy-compatible reaction, it is important to know all the components of the vaccine to conduct a proper study.

Immunogenicity and safety of Southern Hemisphere inactivated quadrivalent influenza vaccine: a Phase III, open-label study of adults in Brazil

Abstract The World Health Organization influenza forecast now includes an influenza B strain from each of the influenza B lineages (B/Yamagata and B/Victoria) for inclusion in seasonal influenza vaccines. Traditional trivalent influenza vaccines include an influenza B strain from one lineage, but because two influenza B lineages frequently co-circulate, the effectiveness of trivalent vaccines may be reduced in seasons of influenza B vaccine-mismatch. Thus, quadrivalent vaccines may potentially reduce the burden of influenza compared with trivalent vaccines.In this Phase III, open-label study, we assessed the immunogenicity and safety of Southern Hemisphere inactivated quadrivalent influenza vaccine (Fluarix™ Tetra) in Brazilian adults (NCT02369341). The primary objective was to assess hemagglutination-inhibition antibody responses against each vaccine strain 21 days after vaccination in adults (aged ≥18–60 years) and older adults (aged >60 years). Solicited adverse events for four days post-vaccination, and unsolicited adverse events and serious adverse events for 21 days post-vaccination were also assessed.A total of 63 adults and 57 older adults received one dose of inactivated quadrivalent influenza vaccine at the beginning of the 2015 Southern Hemisphere influenza season. After vaccination, in adults and older adults, the hemagglutination-inhibition titers fulfilled the European licensure criteria for immunogenicity. In adults, the seroprotection rates with HI titer ≥1:40 were 100% (A/H1N1), 98.4% (A/H3N2), 100% (B/Yamagata), and 100% (B/Victoria); in older adults were 94.7% (A/H1N1), 96.5% (A/H3N2), 100% (B/Yamagata), and 100% (B/Victoria). Pain was the most common solicited local adverse events in adults (27/62) and in older adults (13/57), and the most common solicited general adverse events in adults was myalgia (9/62), and in older adults were myalgia and arthralgia (both 2/57). Unsolicited adverse events were reported by 11/63 adults and 10/57 older adults.The study showed that inactivated quadrivalent influenza vaccine was immunogenic and well-tolerated in Brazilian adults and older adults.

Improved immunogenicity of Newcastle disease virus inactivated vaccine following DNA vaccination using Newcastle disease virus hemagglutinin-neuraminidase and fusion protein genes

The present study describes the development of DNA vaccines using the hemagglutinin-neuraminidase (HN) and fusion (F) genes from AF2240 Newcastle disease virus strain, namely pIRES/HN, pIRES/F and pIRES-F/HN. Transient expression analysis of the constructs in Vero cells revealed the successful expression of gene inserts in vitro. Moreover, in vivo experiments showed that single vaccination with the constructed plasmid DNA (pDNA) followed by a boost with inactivated vaccine induced a significant difference in enzyme-linked immunosorbent assay antibody levels (p < 0.05) elicited by either pIRES/F, pIRES/F+ pIRES/HN or pIRES-F/HN at one week after the booster in specific pathogen free chickens when compared with the inactivated vaccine alone. Taken together, these results indicated that recombinant pDNA could be used to increase the efficacy of the inactivated vaccine immunization procedure.

Assessment of the safety and efficacy of low pathogenic avian influenza (H9N2) virus in inactivated oil emulsion vaccine in laying hens

In Korea, several outbreaks of low pathogenic AI (H9N2) viral infections leading to decreased egg production and increased mortality have been reported on commercial farms since 1996, resulting in severe economic losses. To control the H9N2 LPAI endemic, the Korea Veterinary Authority has permitted the use of the inactivated H9N2 LPAI vaccine since 2007. In this study, we developed a killed vaccine using a low pathogenic H9N2 AI virus (A/chicken/Korea/ADL0401) and conducted safety and efficacy tests in commercial layer farms while focusing on analysis of factors that cause losses to farms, including egg production rate, egg abnormality, and feed efficiency. The egg production rate of the control group declined dramatically 5 days after the challenge. There were no changes in feed consumption of all three groups before the challenge, but rates of the control declined afterward. Clinical signs in the vaccinated groups were similar, and a slight decline in feed consumption was observed after challenge; however, this returned to normal more rapidly than the control group and commercial layers. Overall, the results of this study indicate that the safety and efficacy of the vaccine are adequate to provide protection against the AI field infection (H9N2) epidemic in Korea.

A glycoprotein E gene-deleted bovine herpesvirus 1 as a candidate vaccine strain

A bovine herpesvirus 1 (BoHV-1) defective in glycoprotein E (gE) was constructed from a Brazilian genital BoHV-1 isolate, by replacing the full gE coding region with the green fluorescent protein (GFP) gene for selection. Upon co-transfection of MDBK cells with genomic viral DNA plus the GFP-bearing gE-deletion plasmid, three fluorescent recombinant clones were obtained out of approximately 5000 viral plaques. Deletion of the gE gene and the presence of the GFP marker in the genome of recombinant viruses were confirmed by PCR. Despite forming smaller plaques, the BoHV-1△gE recombinants replicated in MDBK cells with similar kinetics and to similar titers to that of the parental virus (SV56/90), demonstrating that the gE deletion had no deleterious effects on replication efficacy in vitro. Thirteen calves inoculated intramuscularly with BoHV-1△gE developed virus neutralizing antibodies at day 42 post-infection (titers from 2 to 16), demonstrating the ability of the recombinant to replicate and to induce a serological response in vivo. Furthermore, the serological response induced by recombinant BoHV-1△gE could be differentiated from that induced by wild-type BoHV-1 by the use of an anti-gE antibody ELISA kit. Taken together, these results indicated the potential application of recombinant BoHV-1 △gE in vaccine formulations to prevent the losses caused by BoHV-1 infections while allowing for differentiation of vaccinated from naturally infected animals.

Protection of chickens against infectious bronchitis virus with a multivalent DNA vaccine and boosting with an inactivated vaccine

The protective efficacy of DNA plasmids encoding avian infectious bronchitis virus (IBV) S1, N, or M protein was investigated in chickens. Chickens were inoculated monovalently (with plasmid pVAX1-16S1, pVAX1-16M, or pVAX1-16N alone) or multivalently (combination of the three different plasmids, pVAX1-16S1/M/N). A prime-boost immunization protocol against IBV was developed. Chickens were immunized with the multivalent DNA vaccine twice and then boosted with an inactivated vaccine once. Antibody titers of the chickens immunized with pVAX1-16S1/M/N were much higher than those of the monovalent groups (p < 0.01). A protective rate up to 90% was observed in the pVAX1-16S1/M/N group. The serum antibody titers in the prime-boost birds were significantly higher than those of the multivalent DNA vaccine group (p < 0.01) but not significantly different compared to the inactivated vaccine group at 49 days of age. Additionally, the prime-boost group also showed the highest level of IBV-specific cellular proliferation compared to the monovalent groups (p < 0.01) but no significant difference was found compared to the multivalent DNA vaccine group, and the prime-boost group completely protected from followed viral challenge.

Evaluating the effectiveness of an inactivated vaccine from Anaplasma marginale derived from tick cell culture / Avaliação da eficácia de uma vacina inativada de Anaplasma marginale derivada de cultura de células de carrapato

The protective efficacy of an inactivated vaccine from Anaplasma marginale that was cultured in tick cells (IDE8) for use against bovine anaplasmosis was evaluated. Five calves (Group 1) were inoculated subcutaneously, at 21-day intervals, with three doses of vaccine containing 3 × 10(9) A. marginale initial bodies. Five control calves received saline solution alone (Group 2). Thirty-two days after the final inoculation, all the calves were challenged with approximately 3 × 10(5) erythrocytes infected with A. marginale high-virulence isolate (UFMG2). The Group 1 calves seroconverted 14 days after the second dose of vaccine. After the challenge, all the animals showed patent rickettsemia. There was no significant difference (p > 0.05) between the Group 1 and 2 calves during the incubation period, patency period or convalescence period. All the animals required treatment to prevent death. The results suggest that the inactivated vaccine from A. marginale produced in IDE8 induced seroconversion in calves, but was not effective for preventing anaplasmosis induced by the UFMG2 isolate under the conditions of this experiment.

Foi avaliada a eficácia de uma vacina protetora para Anaplasma marginale cultivada em células de carrapato (IDE8) para uso contra a anaplasmose bovina. Cinco bezerros (Grupo 1) foram inoculados por via subcutânea com três doses, intervalados de 21 dias, de vacina contendo 3 × 10(9) corpúsculos iniciais de A. marginale inicial. Cinco bezerros do grupo controle receberam apenas solução salina (Grupo 2). Trinta e dois dias após a inoculação final, todos os bezerros foram desafiados com aproximadamente 3 × 10(5) eritrócitos infectados com isolado de A. marginale alta virulência (UFMG2). Os bezerros do Grupo 1 soroconverteram-se 14 dias após a segunda dose da vacina. Após o desafio, todos os animais mostraram riquestsemia patente. Não houve diferença significativa (p > 0,05) entre bezerros do Grupo 1 e 2 em período de incubação, período de patência, ou período de convalescença. Todos os animais necessitaram de tratamento para prevenir a morte. Os resultados sugerem que uma vacina inativada de A. marginale, produzida em IDE8, induz soroconversão em bezerros, mas não é eficaz na prevenção de anaplasmose induzida pelo isolado UFMG2 nas condições deste experimento.

Green propolis phenolic compounds act as vaccine adjuvants, improving humoral and cellular responses in mice inoculated with inactivated vaccines

Adjuvants play an important role in vaccine formulations by increasing their immunogenicity. In this study, the phenolic compound-rich J fraction (JFR) of a Brazilian green propolis methanolic extract stimulated cellular and humoral immune responses when co-administered with an inactivated vaccine against swine herpesvirus type 1 (SuHV-1). When compared to control vaccines that used aluminium hydroxide as an adjuvant, the use of 10 mg/dose of JFR significantly increased (p < 0.05) neutralizing antibody titres against SuHV-1, as well as the percentage of protected animals following SuHV-1 challenge (p < 0.01). Furthermore, addition of phenolic compounds potentiated the performance of the control vaccine, leading to increased cellular and humoral immune responses and enhanced protection of animals after SuHV-1 challenge (p < 0.05). Prenylated compounds such as Artepillin C that are found in large quantities in JFR are likely to be the substances that are responsible for the adjuvant activity.

Evaluation of experimental vaccines for bovine viral diarrhea in bovines, ovines and guinea pigs / Evaluación de vacunas experimentales para la diarrea viral bovina en bovinos, ovinos y cobayos

The bovine viral diarrhea virus (BVDV) infection control should be based on elimination of persistently infected animals and on immunization through vaccination, to prevent fetal infection. However, the efficacy of inactivated BVDV vaccines is variable due to its low immunogenicity. This study evaluated the humoral immune response against homologous and heterologous strains of 7 inactivated BVDV vaccines, in bovines and two experimental models (ovine and guinea pig) which might be used to test candidate vaccines. Vaccines formulated with BVDV Singer, Oregon, NADL, and multivalent, induced seroconversion in the three animal models studied, reaching antibody titres higher than 2. Vaccine containing 125C -genotype 2- only induced a low antibody response in ovine, while VS-115 NCP vaccine was not immunogenic. Furthermore, bovine sera at 60 dpv presented homologous as well as heterologous antibody response, indicating a high degree of cross-reactivity among the strains studied. However, when bovine sera were tested against the Argentine field strain 00-693, they showed the lowest levels of cross-reactivity, suggesting the need of continued surveillance to identify and characterize emerging field BVDV strains. Finally, optimal correlations between bovine-ovine and bovine-guinea pig models were observed, indicating that two alternative species could replace bovines when testing the immunogenicity of BVDV candidate vaccines.

El control del virus de la diarrea viral bovina (VDVB) se basa en la eliminación de animales persistentemente infectados, y la inmunización de hembras para prevenir infecciones fetales. La eficiencia de estas vacunas es variable por su baja inmunogenicidad. Se evaluó la respuesta inmune humoral contra virus homólogos y heterólogos de 7 vacunas experimentales inactivadas del VDVB en bovinos y en dos modelos experimentales (ovinos y cobayos). Las vacunas conteniendo VDVB Singer, Oregon, NADL y polivalentes indujeron seroconversión en los tres modelos y se alcanzaron títulos de anticuerpos mayores de 2. La vacuna con VDVB genotipo 2 VS-115, NCP, no resultó inmunogénica. La vacuna genotipo 2 125C sólo indujo baja respuesta humoral en ovinos, mientras que la VS-115, NCP, no resultó inmunogénica. En bovinos se determinó la respuesta a virus homólogos y heterólogos a 60 dpv, lo que indica un alto grado de inmunidad cruzada entre la mayoría de las cepas estudiadas. Cuando los sueros bovinos fueron ensayados con la cepa de campo de Argentina 00-693, los niveles de reacción cruzada fueron más bajos; esto sugiere la necesidad de una vigilancia epidemiológica sostenida a fin de identificar y caracterizar las cepas emergentes del VDVB. La óptima correlación en el modelo bovino-ovino y bovino-cobayo indica su utilidad para evaluar la inmunogenicidad de vacunas inactivadas de VDVB.

An inactivated vaccine to control the current H9N2 low pathogenic avian influenza in Korea

The H9N2 subtype low pathogenic avian influenza is one of the most prevalent avian diseases worldwide, and was first documented in 1996 in Korea. This disease caused serious economic loss in Korea's poultry industry. In order to develop an oil-based inactivated vaccine, a virus that had been isolated in 2001 (A/chicken/Korea/01310/ 2001) was selected based on its pathogenic, antigenic, and genetic properties. However, in animal experiments, the efficacy of the vaccine was found to be very low without concentration of the antigen (2(7) to 2(10) hemagglutinin unit). In order to overcome the low productivity, we passaged the vaccine candidate virus to chicken eggs. After the 20th passage, the virus was approximately ten times more productive compared with the parent virus. For the most part, the passaged virus maintained the hemagglutinin cleavage site amino acid motif (PATSGR/GLF) and had only three amino acid changes (T133N, V216G, E439D, H3 numbering) in the hemagglutinin molecule, as well as 18 amino acid deletions (55-72) and one amino acid change (E54D) in the NA stalk region. The amino acid changes did not significantly affect the antigenicity of the vaccine virus when tested by hemagglutination inhibition assay. Though not complete, the vaccine produced after the 20th passage of the virus (01310 CE20) showed good protection against a homologous and recent Korean isolate (A/chicken/Korea/Q30/2004) in specific pathogen- free chickens. The vaccine developed in this study would be helpful for controlling the H9N2 LPAI in Korea.

Dengue vaccines: problems and prospects.

The extent of cumulative disease burden caused by dengue virus has attained an unprecedented level in recent times with sharp increase in the size of human population at risk. Dengue disease presents highly complex medical, economic and ecologic problems. The surge in publications on the development of dengue vaccines, taking advantage of new generation of biotechnology techniques indicates the profound interest and urgency in the scientific and medical communities in combating this disease. This review summarizes the importance of critical subjects like pathogenesis of dengue haemorrhagic fever and inadequacy of animal model that have adversely affected dengue vaccine development. Further, the remarkable progresses so far made in dengue vaccine research not only employing a diverse range of new strategies but also re-using old techniques to improve the existing vaccines, have been presented. The efficacy and safety of some of the new vaccine candidates have been evaluated and proven in human preclinical/clinical trials. Besides the technical advancement in vaccine development, vaccine safety and vaccine formulation have been examined.

Trial to increase the duration of neutralizing antibodies in cattle vaccinated with inactivated FMD vaccine

Inactivated FMD vaccine is weakly immunogenic and multiple vaccinations at four-month intervals are necessary for the prevention of the disease. Our results revealed that in cyclophosphamide treated animals, the antibody titers remained protecting up to 35 weeks post vaccination, while in non treated group, the animals became susceptible to infection 19 weeks post vaccination. So, it is possible to increase the duration of neutralizing antibodies in serum when a low single dose of cyclophosphamide is administered four days before vaccination with aluminum hydroxide-saponin FMD vaccine and this will increase the intervals between vaccinations and decrease the commercialization costs of vaccination programs

Effect of tetravalent vaccine as control measure for calf diarrhea through dam vaccination

The present study was conducted on 80 pregnant buffalo dams and their neonates, of which 20 pregnant dam were injected s/c two times, at 8 weeks before the expected time of calving and again 4 weeks later with tetravalent vaccine [Lactovac vet.] to control neonatal calf diarrhea. The rest of dams were used as a control group. Immunoglobulin [IgM and IgA] concentration levels and some biochemical parameters [total protein, albumin and globulin] were measured in serum of buffalo dams prior to vaccination and after calving and compared with those of non vaccinated dams. The means of serum immunoglobulins and [total protein, albumin and globulin] of vaccinated dams after calving were increased when compared to those of control non vaccinated dams after calving. A high significant difference was noticed between serum IgM of vaccinated and non vaccinated dams after calving. High significant differences were observed between 36-48 h old calves of both groups with regard to serum IgG, IgM and IgA. High significant differences were observed between colostral IgG, IgM and IgA of vaccinated and non vaccinated dams. High significant reverse correlations were noticed between serum IgM of vaccinated dams and their calves as well as between colostral IgG of non vaccinated dams and serum of their calves. A significant positive correlation between colostral IgA of vaccinated dams and serum of IgA of their calves was observed. The previous results of immunization of pregnant buffalo dams with [lactovac vet] revealed that there was a striking increase in the level of both serum and colostral immunoglobulins of vaccinated dams in comparison with non vaccinated dams as well as in serum of 36-48 h old calves born to vaccinated darns in comparison to those born to non vaccinated darns. Clinical observations of neonates [test and control groups] clearly demonstrated that [Lactovac vet] induced a pronounced decrease in the incidence of diarrhea, pneumonia and mortality rates. It is highly recommended that a program depending on vaccination of darns during late gestation with [Lactovac-vet.] could successfully be used to protect neonates against the most prevalent diarrhoegenic agents and minimize a great economic loss

Rotavirus vaccine: current status & future prospects.

A number of rotavirus vaccines, live attenuated, killed, and subunit, genetically engineered vaccines have been developed to control infantile diarrhoea. Field trials in several parts of the world have met with moderate or no success as the vaccinees failed to develop heterotypic protection. The failure of vaccine to control rotavirus diarrhoea may be due to the lack of understanding of the neonatal mucosal immune response, evolution of reassortant strains in nature and seasonal re-emergence of different types of strains in the field situation.

Strategies for production of a potential candidate vaccine for cholera.

First attempt at cholera vaccination was made by Jaime Ferran in 1884. Since then, a variety of strategies and methods have been evolved to create a safe, efficacious vaccine against cholera. For the first few years emphasis was on the development of parenteral vaccines. However, as a result of accumulation of a tremendous amount of knowledge, not only on Vibrio cholerae-the causative agent, but also on its interaction with the host, emphasis has shifted towards the development of oral vaccines. Two such vaccines, one killed, a whole cell/B subunit combination vaccine and the other a live attenuated one, have shown promise. The combination vaccine in its present state of development confers only a transient protection in young children, while the live attenuated one produces adverse reaction. To combat these, various strategies are being evolved. In one attempt, a potential candidate vaccine strain has been constructed from a non-reactogenic clinical isolate of V. cholerae, which is devoid of all known major virulence genes and is also a good colonizer. In animal studies this construct has shown considerable promise. This review discusses the various strategies that have been employed so far in the quest for an ideal cholera vaccine.

Evaluation of effectiveness of mouse brain inactivated Japanese encephalitis vaccine produced in India.

Efficacy of mouse brain inactivated Japanese encephalitis vaccine was evaluated by studying the immune status of volunteers 1,2,3,4.5 and 7.5 yr after immunization. Neutralizing (N) antibody which is protective and found to correlate with the immunity after vaccination was estimated in serum by plaque reduction neutralizing test on chick embryo cell monolayer. Mean N-antibody titres of 3.25 (pre-booster) and 3.6, 2.8, 2.06, 1.85 and 1.50 log10 were observed post-booster, and 1,2,3, and 4.5 yr of immunization in volunteers who received complete immunization (3 doses). All the volunteers retained more than 1.0 log10 titre of protective N-antibody in spite of the loss of 0.8, 0.74, 0.21 and 0.35 log10 after 1,2,3, and 4.5 yr respectively. Similarly mean N-antibody titres of 1.6, 3.25, 2.4, 2.25, 1.92 and 1.60 log10 were observed pre-booster, after a single booster dose, and 1,2,3 and 4.5 yr of vaccination in individuals who received only a single booster dose. Ten serum samples of volunteers tested after 7.5 yr of vaccination showed that those who were in constant contact with JE virus (n = 7) in the laboratory maintained high levels of N-antibody whereas others (n = 3) showed a fall in titre indicating the necessity of a booster dose.

Effect of pregnancy on protection of mice immunized by Japanese encephalitis virus & its experimental inactivated vaccine.

The effect of pregnancy on the protective immune response of mice to tissue culture-derived inactivated Japanese encephalitis (JE) Nakayama vaccine and to live sublethal doses of JE virus, was studied. Thirty per cent protection was found in mice, immunized with three doses of inactivated vaccine, before pregnancy and challenged after delivery. In contrast, all the mice immunized with two sublethal doses of JEV tolerated the challenge under similar condition.