Effects of different immunomodulating liposome-based adjuvants and injection sites on immunogenicity in pigs.

Vaccine adjuvants, such as liposome-based cationic adjuvant formulations (CAFs), are able to boost immune responses and, by incorporation of distinct immunomodulators, steer immunity towards a desired direction in mice, non-human primates and humans, while less studied in pigs. Here we used commercial pigs to investigate polarizing adjuvant effects of CAFs with immunomodulators: C-type lectin receptor ligands trehalose-6,6'-dibehenate and monomycolyl glycerol, toll-like receptor 3 ligand Poly(I:C) or retinoic acid. Vaccines were formulated with a recombinant Chlamydia model protein antigen and administered via three injection routes. All adjuvants significantly increased antigen-specific IgG in serum, compared to non-adjuvanted antigen. Administering the vaccines through intramuscular and intraperitoneal routes induced significantly higher antigen-specific IgG and IgA serum antibodies, than the perirectal route. Although immunizations triggered cell-mediated immunity, no significant differences between adjuvants or injection sites were detected. Genes depicting T cell subtypes revealed only minor differences. Our findings suggest that specific signatures of the tested adjuvant immunomodulation do not translate well from mice to pigs in standard two-dose immunizations. This study provides new insights into immune responses to CAFs in pigs, and highlights that adjuvant development should ideally be carried out in the intended species of interest or in models with high predictive validity/translational value.

Retinoic acid modulates PTGDR promoter activity

Background and Objective: Vitamin A has been linked to the development of allergic diseases although its role is not fully understood, Retinoic acid (RA), a metabolite of Vitamin A, has been previously associated with the prostaglandin pathway, and PTGDR, a receptor of PGD2, has been proposed as a candidate gene in allergy and asthma. Considering the role of PTGDR in allergy, the goal of this study was o analyze the effect of RA on the activation of the promoter region of the PTGDR gene. Methods: A549 lung epithelial cells were transfected with 4 combinations of genetic variants of the PTGDR promoter and stimulated with all-trans RA (ATRA); luciferase assays were performed using the Dual Luciferase Reporter System, and real-time quantitative polymerase chain reaction was used to measure the expression of PTGDR, CYP26A1, RARA, RARB, RARG , and RXRA in basal A549 cell cultures and after ATRA treatment. We also performed an in silico analysis. Results: After ATRA treatment increased expression of CYP26A1 (12-fold) and RARB (4-fold) was detected. ATRA activated PTGDR promoter activity in transfected cells (P<.001) and RA response element sequences were identified in silico in this promoter region. Conclusions: RA modulated PTGDR promoter activity. Differential response to RA and to new treatments based on PTGDR modulation could depend on genetic background in allergic asthmatic patients (AU)

Introducción y Objetivo: La vitamina A se ha relacionado con el desarrollo de las enfermedades alérgicas, si bien su papel no se comprende en su totalidad. El ácido retinoico, un metabolito de la vitamina A, se ha asociado previamente con la ruta de las prostaglandinas. Además, PTGDR, uno de los receptores de PGD2, se ha propuesto como un gen candidato en la alergia y el asma. Considerando el papel de PTGDR en la alergia, el objetivo de este estudio fue analizar el efecto del ácido retinoico sobre la activación de la región promotora del gen PTGDR. Métodos: Se utilizó la línea celular A549 de epitelio de pulmón. Las células fueron transfectadas con cuatro combinaciones de las variantes génicas de PTGDR y fueron estimuladas con ácido retinoico todo-trans (ATRA). Los ensayos de Luciferasa se llevaron a cabo mediante el sistema Dual Luciferase Reporter System. Se realizaron análisis de RT-qPCR para medir la expresión basal de PTGDR, CYP26A1, RARA, RARB, RARG y RXRA de los cultivos de A549 tras el tratamiento con ATRA. Se realizaron también análisis bioinformáticos. Resultados: Se encontraron diferencias significativas en la actividad promotora entre las variantes haplotípicas tras la transfección en la línea celular A549. Tras el tratamiento con ATRA se detectó un incremento de la expresión de CYP26A1 (12 veces) y RARB (4 veces). El ácido retinoico activó la actividad promotora de PTGDR en las células transfectadas (p<0,001). Se identificaron secuencias de Elementos de Respuesta a Ácido Retinoico (RARE) in silico en la región promotora de PTGDR. Conclusiones: El ácido retinoico modula la actividad promotora de PTGDR . Esto podría explicar las diferencias en los efectos del ácido retinoico y en las respuestas a los nuevos tratamientos de la enfermedad alérgica basados en la modulación del receptor PTGDR (AU)