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Introducción: La vacuna antialérgica de segunda generación PROLINEM-DS está compuesta por alérgenos del ácaro Dermatophagoides siboney y la combinación de adyuvantes: proteoliposoma de N. meningitidis B y gel de hidróxido de aluminio. La adsorción del alérgeno es relevante para la seguridad y eficacia clínica de las vacunas adsorbidas en gel de hidróxido de aluminio en estudios previos se demostró la influencia negativa de los iones fosfato en la adsorción del alérgeno. Objetivo: Evaluar la inmunogenicidad y capacidad protectora de cuatro variantes de formulación obtenidas dentro del espacio de diseño de la vacuna PROLINEM DS. Métodos: Se emplearon 4 variantes de formulación con diferentes contenidos de tampón fosfato salino y gel de hidróxido de aluminio. Se administraron a ratones BALB/c 3 dosis subcutáneas una por semana. Luego, los ratones fueron sometidos a reto alergénico por aerosol. Resultados: Todas las variantes indujeron anticuerpos IgG1 e IgG2a alérgeno específico. Este efecto se correlacionó con el balance de citoquinas proinflamatorias Th1/Th2 en los pulmones y en los ganglios. La variante con reducción de tampón fosfato salino y gel de hidróxido de aluminio fue la de mayor índice IgG/IgE después de la vacunación. Esta relación muestra, en una variable, el equilibrio entre los componentes potencialmente bloqueadores y efectores. La tolerancia local en el lugar de la inyección mostró una reducción de los granulomas en los ratones vacunados con menos gel de hidróxido de aluminio. Conclusiones: La reducción del contenido de gel de hidróxido de aluminio y fosfatos se consideran mejoras farmacéuticas sin inconvenientes en cuanto a la inmunogenicidad de esta vacuna con un perfil de seguridad satisfactorio para futuros ensayos clínicos en humanos.

Introduction: The second generation anti allergic vaccine named PROLINEM DS is based on allergens from D. siboney house dust mite and a combination adjuvant containing PL and Alum. Allergen adsorption is relevant both safety and clinical efficacy in alum-adsorbed vaccines. Negative influence of phosphate ions on allergen adsorption was demonstrated in previous researches. Objective: To evaluate immunogenicity and protective efficacy of four variants obtained within design space of PROLINEM DS vaccine. Methods: Four variants were differentiated from each other by both phosphate and alum contents. Balb/c mice were administered with 3 doses by subcutaneous route. Further, mice were subjected to allergen aerosol challenge. Results: Specific IgG1 and IgG2a antibodies were induced by four vaccine variants. It was correlated with pro inflammatory cytokines balance Th1/Th2 both in lungs and lymphatic nodes. Formulation with lower PBS and Alum levels showed the highest IgG/IgE ratio at the end of vaccination schedule. This ratio shows in one variable the balance between potentially blocking and effector components. Mice injected with lower level of Alum showed a reduction of granuloma size in the site of vaccine administration. Conclusion: Decrease both alum and phosphate contents were a pharmaceutical improvement for antiallergic vaccines formulation. Safety and efficacy in this vaccine are crucial for future human clinical trials.

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RESUMO

The outer-membrane-derived proteoliposome (PL) of Neisseria meningitidis has been reported as a potent vaccine adjuvant, inducing a Th1-skewed response. This work aimed to assess the immunogenicity of a novel anti-allergic vaccine candidate based on allergens from Dermatophagoides siboney house dust mite and a combination adjuvant containing PL and Alum. In a preventative experimental setting, BALB/c mice were administered with three doses containing 2 µg of Der s1 and 0.4 µg Der s2 allergen, PL and Alum, at 7 days intervals, by subcutaneous route. Furthermore, mice were subjected to an allergen aerosol challenge for 6 consecutive days. Serum IgE, IgG1, and IgG2a allergen-specific antibodies were assessed by ELISA. Cytokine levels in supernatants of D. siboney stimulated lymphocyte cultures and in bronchoalveolar lavage (BAL) were measured by ELISA. Lung tissues were subjected to histological examination. The vaccine prevented the development of both, systemic (IgE) and local allergic responses (featuring lower IL-4, and IL-5 levels in BAL) upon allergen exposure by the inhalant route. Histological examination showed also a diminished allergic inflammatory response in the lungs. After the allergen challenge, cytokine levels in stimulated lymphocyte cultures showed lower values of IL-13 and augmented IFN-γ and IL-10. The vaccine induced a mixed IgG2a/IgG1 antibody response; although only IgG2a was PL-dependent. Both, IgG1/IgE and IgG2a/IgE ratios, showed significantly greater values in vaccinated mice. The findings support a preventative anti-allergic effect associated with the induction of a Th1-like IFN-γ/IL-10 response. IgG1/IgE and IgG2a/IgE ratios could be useful biomarkers for translation into clinical trials.