Vacunación en neonatos contra la enfermedad resurgente pertussis: un desafío, una estrategia

La Declaración del Milenio de las Naciones Unidas, firmada en septiembre de 2000, comprometió a los líderes mundiales a luchar contra la pobreza, el hambre, las enfermedades, el analfabetismo, la degradación medioambiental y la discriminación de la mujer. En dicha declaración se fijaron objetivos y metas a ser cumplidas para el año 2015. Varios de dichos objetivos y metas están directamente relacionados con la salud. Gracias al trabajo conjunto enmarcado en dicha declaración se logró reducir en un 53% la tasa de mortalidad en los menores de cinco años. Sin embargo todavía cada año se registran alrededor de 2 millones de muertes en lactantes menores de 6 meses debido a infecciones 1. En el año 2015, un dato preocupante fue que el 45% de los fallecimientos ocurridos en el grupo de los niños menores de 5 años se detectó en el primer mes de vida 2. Muchas de estas muertes fueron debidas a enfermedades que son prevenibles mediante la vacunación pero que por la corta edad de los niños no alcanzan a completar el esquema de vacunación que brinda protección. Para muchas enfermedades la vacunación comienza a las 6-8 semanas de edad, pero la primera dosis no brinda protección inmediata y en general se requieren de múltiples dosis, lo que lleva a la vulnerabilidad en los primeros 6 meses de vida. En un esfuerzo por reducir la tasa de mortalidad en los menores de 5 años a menos de 25 por cada 1.000 nacidos vivos para fines de 2030, se están explorando e implementando una serie de estrategias que incluyen entre otras, la inmunización durante el embarazo 3. Esta estrategia aunque es muy prometedora para varios patógenos, incluidos aquellos que provocan enfermedades como pertussis e influenza, es relativamente reciente, y además tiene un valor limitado para los casi 2,6 millones de bebés que nacen prematuramente y que a lo sumo reciben una cantidad restringida de anticuerpos maternos 4. Los avances recientes en la comprensión de la respuesta inmunitaria en neonatos 5 6, han renovado el interés en la inmunización neonatal como una estrategia prometedora y eficaz para reducir la morbilidad y la mortalidad en bebés pequeños. Esta estrategia ya ha sido recomendada y empleada de forma rutinaria al nacer para las vacunas contra la tuberculosis [Bacilo de Calmette-Guérin (BCG)], hepatitis B (VHB) y polio [vacuna oral antipoliomielítica (OPV) o vacuna antipoliomielítica inactivada (IPV)]. Estos antecedentes son claves para el diseño de vacunas y estrategias que impacten positivamente en la protección de los recién nacidos y durante el periodo neonatal, que en humanos se define como los primeros 28 días de vida. En este contexto, durante mi trabajo de tesis abordamos en el modelo murino el empleo de la estrategia de inmunización neonatal contra pertussis, una enfermedad respiratoria resurgente. Sustenta este objetivo el hecho de que: a) la enfermedad denominada pertussis o tos convulsa afecta gravemente a los recién nacidos y lactantes; (b) que el nacimiento es un punto práctico de contacto con la atención médica que permite asegurar buenas coberturas de vacunación en el neonato, c) que la combinación de la inmunización maternal y la neonatal podría sinergizar los beneficios en la prevención en los recién nacidos; (d) el posible beneficio de la protección para los bebés prematuros para quienes la transferencia de anticuerpos maternos es limitada, con un mayor riesgo de infecciones graves durante la infancia.Facultad de Ciencias Exacta

Pertussis epidemiology in Argentina: TRENDS after the introduction of maternal immunisation

Data on the impact of the recently recommended maternal pertussis vaccination are promising, but still insufficient to universalise this approach. We thus compared the epidemiological data prior to the implementation of this vaccination strategy in Argentina (2012) with the figures reported after 2012. During that 2010–2016 period, two outbreaks occurred, one in 2011 and another in 2016. In the former, the incidence was 6.9/100 000 inhabitants and the casefatality rate 2.6%. Thereafter, a decline in incidence was detected until 2014. During 2015 and 2016 an increase in the incidence transpired, but this rise was fortunately not accompanied by one in the case fatality ratio. Indeed, in 2016 the case fatality ratio was the lowest (0.6%). Moreover, during the 2016 outbreak, the incidence (3.9/100 000 inhabitants) and the case severity detected in the most vulnerable population (infants 0–2 months) were both lower than those in 2011. Consistent with this pattern, in 2016, in the most populated province of Argentina (Buenos Aires), the case percentage with laboratory-positive results indicating a high number of symptoms (59.1% of the total cases) diminished compared with that detected in the 2011 outbreak without maternal immunisation (71.9%). Using the mathematical model of pertussis transmission we previously designed, we assessed the effect of vaccination during pregnancy on infant incidence. From comparisons between the epidemiological data made through calculations, emerged the possibility that vaccinating women during pregnancy would benefit the infants beyond age 2 months, specifically in the 2–12-month cohort.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

Use of a Neonatal-Mouse model to characterize vaccines and strategies for overcoming the high susceptibility and severity of pertussis in early life

Newborns and unvaccinated infants, compared to other age groups, are more susceptible to pertussis infection, manifesting severe symptoms leading to a higher mortality. The recent increase in pertussis cases demands more effective strategies to overcome this major health problem. In parallel with maternal-immunization, neonatal-immunization (NI) is a strategy needing revision. Here, using the intranasal-challenge-mouse-model we evaluated the protective capacity of NI in both naïve-mice and those with maternally acquired immunity. We tested our acellular-vaccine-candidate based on outer-membrane-vesicles derived from Bordetella pertussis (OMVP) that induces Th2-profile but also the recommended Th-profile for protection: Th1/Th17-profile and CD4 T-memory-cells that reside in the lungs. Commercial acellular-vaccine (aP) and whole cell-vaccine (wP) inducing mainly Th2-profile and Th1-profile, respectively, were also tested. Analyzing the induced immunity and protection capability of NI included in 1- or 2-dose schedules with the same or different types of vaccine, we detected that the aP-vaccine administered in either single- or 2-dose schedules protected against sublethal B. pertussis infection. Schedules consisting of doses of aP neonatally and of OMVP or wP vaccine during infancy greatly reduced bacterial lung colonization while inducing the highest levels of high-avidity anti-pertussis toxin (PTx) IgG. That OMVP or wP neonatal dose did not interfere with the protection of transferred maternal immunity was especially encouraging. Moreover, OMVP- or wP used as a neonatal dose enhanced the quality of the humoral immune response in immunized pups. Antibodies generated by OMVP-or wP-vaccinated mice born to aP-immunized mothers were of higher avidity than those from mice that harbored only maternal immunity; but when mothers and neonates were immunized with the same aP-vaccine, the humoral response in the neonates was partially suppressed through the blunting of the level of anti-PTx IgG induced by the neonatal aP dose. These results demonstrated that neonatal immunization is a possible strategy to be considered to improve the current pertussis epidemiology. For neonates without maternal-immunity, mixed-vaccination schedules that include the aP- and OMVP-vaccines appear to be the most appropriate to induce protection in the pups. For offspring from immune mothers, to avoid blunting-effect, NI should be carried out with vaccines other than those applied during pregnancy.Fil: Martin Aispuro, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Ambrosis, Nicolás Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Zurita, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Gaillard, María Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Bottero, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Hozbor, Daniela Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; Argentin

Use of a Neonatal-Mouse Model to Characterize Vaccines and Strategies for Overcoming the High Susceptibility and Severity of Pertussis in Early Life

Newborns and unvaccinated infants, compared to other age groups, are more susceptible to pertussis infection, manifesting severe symptoms leading to a higher mortality. The recent increase in pertussis cases demands more effective strategies to overcome this major health problem. In parallel with maternal-immunization, neonatal-immunization (NI) is a strategy needing revision. Here, using the intranasal-challenge-mouse-model we evaluated the protective capacity of NI in both naïve-mice and those with maternally acquired immunity. We tested our acellular-vaccine-candidate based on outer-membrane-vesicles derived from Bordetella pertussis (OMVP) that induces Th2-profile but also the recommended Th-profile for protection: Th1/Th17-profile and CD4 T-memory-cells that reside in the lungs. Commercial acellular-vaccine (aP) and whole cell-vaccine (wP) inducing mainly Th2-profile and Th1-profile, respectively, were also tested. Analyzing the induced immunity and protection capability of NI included in 1- or 2-dose schedules with the same or different types of vaccine, we detected that the aP-vaccine administered in either single- or 2-dose schedules protected against sublethal B. pertussis infection. Schedules consisting of doses of aP neonatally and of OMVP or wP vaccine during infancy greatly reduced bacterial lung colonization while inducing the highest levels of high-avidity anti-pertussis toxin (PTx) IgG. That OMVP or wP neonatal dose did not interfere with the protection of transferred maternal immunity was especially encouraging. Moreover, OMVP- or wP used as a neonatal dose enhanced the quality of the humoral immune response in immunized pups. Antibodies generated by OMVP-or wP-vaccinated mice born to aP-immunized mothers were of higher avidity than those from mice that harbored only maternal immunity; but when mothers and neonates were immunized with the same aP-vaccine, the humoral response in the neonates was partially suppressed through the blunting of the level of anti-PTx IgG induced by the neonatal aP dose. These results demonstrated that neonatal immunization is a possible strategy to be considered to improve the current pertussis epidemiology. For neonates without maternal-immunity, mixed-vaccination schedules that include the aP- and OMVP-vaccines appear to be the most appropriate to induce protection in the pups. For offspring from immune mothers, to avoid blunting-effect, NI should be carried out with vaccines other than those applied during pregnancy.Instituto de Biotecnologia y Biologia Molecula

Valorización sustentable de derivados de biomasa para aditivos de combustible: producción de levulinato de etilo

El ácido levulínico (LA), derivado de la catálisis ácida de la biomasa lignocelulósica, uno de los pilares del top-twelve building blocks es potencialmente una molécula versátil para la síntesis de sustancias químicas para aplicaciones como aditivos de combustibles, precursores de polímeros y resinas. Por otra parte, la catálisis mediante HPAs es un área bien establecida con beneficios para la realización de procesos no contaminantes y amigables con el medio ambiente. El heteropoliácido con estructura Wells-Dawson (HPA) fue inmovilizado por primera vez en una matriz de sílice mediante la técnica de sol–gel. Estos catalizadores se utilizaron en la esterificación del ácido levulínico con etanol, a 78 ºC, para obtener levulinato de etilo. La síntesis de inclusión del HPA fue satisfactoria y las muestras mantienen intacta su estructura HPA después de la misma. Los tests catalíticos para la reacción de esterificación entre el ácido levulínico y etanol para producir levulinato de etilo han demostrado que el HPA con estructura Wells-Dawson incluido en sílice son catalizadores activos y selectivos para esta reacción. Debe señalarse que el HPA incluido en sílice mantuvo su estructura y actividad catalítica después de dos ciclos consecutivos de reacción. Estos resultados indicaron que estos ácidos sólidos son catalizadores promisorios para la esterificación de ácido levulínico en condiciones de reacción heterogénea.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Ciencias Aplicada

Valorización sustentable de derivados de biomasa para aditivos de combustible: producción de levulinato de etilo

El ácido levulínico (LA), derivado de la catálisis ácida de la biomasa lignocelulósica, uno de los pilares del top-twelve building blocks es potencialmente una molécula versátil para la síntesis de sustancias químicas para aplicaciones como aditivos de combustibles, precursores de polímeros y resinas. Por otra parte, la catálisis mediante HPAs es un área bien establecida con beneficios para la realización de procesos no contaminantes y amigables con el medio ambiente. El heteropoliácido con estructura Wells-Dawson (HPA) fue inmovilizado por primera vez en una matriz de sílice mediante la técnica de sol–gel. Estos catalizadores se utilizaron en la esterificación del ácido levulínico con etanol, a 78 ºC, para obtener levulinato de etilo. La síntesis de inclusión del HPA fue satisfactoria y las muestras mantienen intacta su estructura HPA después de la misma. Los tests catalíticos para la reacción de esterificación entre el ácido levulínico y etanol para producir levulinato de etilo han demostrado que el HPA con estructura Wells-Dawson incluido en sílice son catalizadores activos y selectivos para esta reacción. Debe señalarse que el HPA incluido en sílice mantuvo su estructura y actividad catalítica después de dos ciclos consecutivos de reacción. Estos resultados indicaron que estos ácidos sólidos son catalizadores promisorios para la esterificación de ácido levulínico en condiciones de reacción heterogénea.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Ciencias Aplicada

Pertussis Vaccine Candidate Based on Outer Membrane Vesicles Derived From Biofilm Culture

Outer membrane vesicles (OMV) derived from Bordetella pertussis—the etiologic agent of the resurgent disease called pertussis—are safe and effective in preventing bacterial colonization in the lungs of immunized mice. Vaccine formulations containing those OMV are capable of inducing a mixed Th1/Th2/Th17 profile, but even more interestingly, they may induce a tissue-resident memory immune response. This immune response is recommended for the new generation of pertussis-vaccines that must be developed to overcome the weaknesses of current commercial acellular vaccines (second-generation of pertussis vaccine). The third-generation of pertussis vaccine should also deal with infections caused by bacteria that currently circulate in the population and are phenotypically and genotypically different [in particular those deficient in the expression of pertactin antigen, PRN(-)] from those that circulated in the past. Here we evaluated the protective capacity of OMV derived from bacteria grown in biofilm, since it was observed that, by difference with older culture collection vaccine strains, circulating clinical B. pertussis isolates possess higher capacity for this lifestyle. Therefore, we performed studies with a clinical isolate with good biofilm-forming capacity. Biofilm lifestyle was confirmed by both scanning electron microscopy and proteomics. While scanning electron microscopy revealed typical biofilm structures in these cultures, BipA, fimbria, and other adhesins described as typical of the biofilm lifestyle were overexpressed in the biofilm culture in comparison with planktonic culture. OMV derived from biofilm (OMVbiof) or planktonic lifestyle (OMVplank) were used to formulate vaccines to compare their immunogenicity and protective capacities against infection with PRN(+) or PRN(-) B. pertussis clinical isolates. Using the mouse protection model, we detected that OMVbiof-vaccine was more immunogenic than OMVplank-vaccine in terms of both specific antibody titers and quality, since OMVbiof-vaccine induced antibodies with higher avidity. Moreover, when OMV were administered at suboptimal quantity for protection, OMVbiof-vaccine exhibited a significantly adequate and higher protective capacity against PRN(+) or PRN(-) than OMVplank-vaccine. Our findings indicate that the vaccine based on B. pertussis biofilm-derived OMV induces high protection also against pertactin-deficient strains, with a robust immune response.Instituto de Biotecnología y Biología Molecula

Narrowing the Knowledge Gaps on the Duration of Transferred Protective Immunity and on Vaccination Frequency

Maternal safety through pertussis vaccination and subsequent maternal–fetal-antibody transfer are well documented, but information on infant protection from pertussis by such antibodies and by subsequent vaccinations is scarce. Since mice are used extensively for maternal-vaccination studies, we adopted that model to narrow those gaps in our understanding of maternal pertussis immunization. Accordingly, we vaccinated female mice with commercial acellular pertussis (aP) vaccine and measured offspring protection against Bordetella pertussis challenge and specific-antibody levels with or without revaccination. Maternal immunization protected the offspring against pertussis, with that immune protection transferred to the offspring lasting for several weeks, as evidenced by a reduction (4–5 logs, p < 0.001) in the colony-forming-units recovered from the lungs of 16-week-old offspring. Moreover, maternal-vaccination-acquired immunity from the first pregnancy still conferred protection to offspring up to the fourth pregnancy. Under the conditions of our experimental protocol, protection to offspring from the aP-induced immunity is transferred both transplacentally and through breastfeeding. Adoptive-transfer experiments demonstrated that transferred antibodies were more responsible for the protection detected in offspring than transferred whole spleen cells. In contrast to reported findings, the protection transferred was not lost after the vaccination of infant mice with the same or other vaccine preparations, and conversely, the immunity transferred from mothers did not interfere with the protection conferred by infant vaccination with the same or different vaccines. These results indicated that aP-vaccine immunization of pregnant female mice conferred protective immunity that is transferred both transplacentally and via offspring breastfeeding without compromising the protection boostered by subsequent infant vaccination. These results—though admittedly not necessarily immediately extrapolatable to humans—nevertheless enabled us to test hypotheses under controlled conditions through detailed sampling and data collection. These findings will hopefully refine hypotheses that can then be validated in subsequent human studies.Facultad de Ciencias Exacta

Narrowing the Knowledge Gaps on the Duration of Transferred Protective Immunity and on Vaccination Frequency

Maternal safety through pertussis vaccination and subsequent maternal–fetal-antibody transfer are well documented, but information on infant protection from pertussis by such antibodies and by subsequent vaccinations is scarce. Since mice are used extensively for maternal-vaccination studies, we adopted that model to narrow those gaps in our understanding of maternal pertussis immunization. Accordingly, we vaccinated female mice with commercial acellular pertussis (aP) vaccine and measured offspring protection against Bordetella pertussis challenge and specific-antibody levels with or without revaccination. Maternal immunization protected the offspring against pertussis, with that immune protection transferred to the offspring lasting for several weeks, as evidenced by a reduction (4–5 logs, p < 0.001) in the colony-forming-units recovered from the lungs of 16-week-old offspring. Moreover, maternal-vaccination-acquired immunity from the first pregnancy still conferred protection to offspring up to the fourth pregnancy. Under the conditions of our experimental protocol, protection to offspring from the aP-induced immunity is transferred both transplacentally and through breastfeeding. Adoptive-transfer experiments demonstrated that transferred antibodies were more responsible for the protection detected in offspring than transferred whole spleen cells. In contrast to reported findings, the protection transferred was not lost after the vaccination of infant mice with the same or other vaccine preparations, and conversely, the immunity transferred from mothers did not interfere with the protection conferred by infant vaccination with the same or different vaccines. These results indicated that aP-vaccine immunization of pregnant female mice conferred protective immunity that is transferred both transplacentally and via offspring breastfeeding without compromising the protection boostered by subsequent infant vaccination. These results—though admittedly not necessarily immediately extrapolatable to humans—nevertheless enabled us to test hypotheses under controlled conditions through detailed sampling and data collection. These findings will hopefully refine hypotheses that can then be validated in subsequent human studies.Facultad de Ciencias Exacta

Narrowing the Knowledge Gaps on the Duration of Transferred Protective Immunity and on Vaccination Frequency

Maternal safety through pertussis vaccination and subsequent maternal–fetal-antibody transfer are well documented, but information on infant protection from pertussis by such antibodies and by subsequent vaccinations is scarce. Since mice are used extensively for maternal-vaccination studies, we adopted that model to narrow those gaps in our understanding of maternal pertussis immunization. Accordingly, we vaccinated female mice with commercial acellular pertussis (aP) vaccine and measured offspring protection against Bordetella pertussis challenge and specific-antibody levels with or without revaccination. Maternal immunization protected the offspring against pertussis, with that immune protection transferred to the offspring lasting for several weeks, as evidenced by a reduction (4–5 logs, p < 0.001) in the colony-forming-units recovered from the lungs of 16-week-old offspring. Moreover, maternal-vaccination-acquired immunity from the first pregnancy still conferred protection to offspring up to the fourth pregnancy. Under the conditions of our experimental protocol, protection to offspring from the aP-induced immunity is transferred both transplacentally and through breastfeeding. Adoptive-transfer experiments demonstrated that transferred antibodies were more responsible for the protection detected in offspring than transferred whole spleen cells. In contrast to reported findings, the protection transferred was not lost after the vaccination of infant mice with the same or other vaccine preparations, and conversely, the immunity transferred from mothers did not interfere with the protection conferred by infant vaccination with the same or different vaccines. These results indicated that aP-vaccine immunization of pregnant female mice conferred protective immunity that is transferred both transplacentally and via offspring breastfeeding without compromising the protection boostered by subsequent infant vaccination. These results—though admittedly not necessarily immediately extrapolatable to humans—nevertheless enabled us to test hypotheses under controlled conditions through detailed sampling and data collection. These findings will hopefully refine hypotheses that can then be validated in subsequent human studies.Facultad de Ciencias Exacta