IDEHU   05542
INSTITUTO DE ESTUDIOS DE LA INMUNIDAD HUMORAL PROF. RICARDO A. MARGNI
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PLGA-OVA microparticles induced an increase of specific IgG asymmetric antibodies in an experimental model of allergen immunotherapy
Autor/es:
APICELLA C; REY ROLDÁN E; CHIAPETTA D; DOKMETJIAN J; GENTILE T
Lugar:
Buenos Aires Argentina
Reunión:
Congreso; World Allergy Congress; 2009
Resumen:
&lt;!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} p.MsoBodyText, li.MsoBodyText, div.MsoBodyText {margin:0cm; margin-bottom:.0001pt; text-align:justify; text-justify:inter-ideograph; mso-pagination:widow-orphan; mso-layout-grid-align:none; text-autospace:none; font-size:12.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; color:black; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&gt; Specific immunotherapy (SIT) is the only potentially curative treatment for those allergic processes mediated by IgE, and it is associated with quantitative and qualitative changes in the specific IgG response. It is also known that asymmetric antibodies (AAbs) behave as antigen blocking due to the presence of a mannose-rich oligosaccharide residue in one of the Fab fragments of the molecule. Futhermore, immunization with particulate antigens increases the proportion of AAbs Mice (balb/c) were sensitised with 3 injections i.p. of ovoalbumin (OVA) adsorbed to Al (OH)3; the allergic status was verified by determination of specific IgE (ELISA) and by the cutaneous anaphylaxis test (PCA). Then mice were subjected to SIT with: 1) OVA entrapped in particles of poly D,L-lactic-co-glycolic acid  (PLGA-OVA), 2) Soluble OVA (OVA-sol) and 3) Polymerised OVA (OVA-pol). After treatment serum levels of specific IgE, IgG1, IgG2a were assessed by ELISA and asymmetric IgG by Concanavalin A affinity chromatography and differential ELISA. Also, we performed the PCA (with and without adsortion of AAbs) and IL-10, IFNγ and IL-4 levels in culture supernatants of splenocytes challenged with OVA were determined by ELISA. Mice treated with PLGA-OVA had higher levels of asymmetric antibodies than non-desensitized mice (39,2± 0.9 % vs 26,7±1.7  % p<0,01). The treatment with soluble OVA did not render an increase in the percentage of specific asymmetric IgG (29.9 ± 2.5%). Nevertheless, no differences in the levels of specific asymmetric IgG were found between mice injected with PLGA or saline and mice before treatment. In PLGA-OVA group a low IgG1 (DO 490 nm IgG1: 1.118 ± 0.067 vs 1.506 ± 0.044 p<0.05) and high IgG2a level (D0 490 nm 0869 ± 0.043 vs 0.625 ± 0.039 p<0.05) was observed together with inhibitory effect in the PCA reaction that reversed in the absence of asymmetric IgG. No significant differences were found in the levels of IgE. IL-10 and IFNγ levels were higher in splenocytes culture supernatants of animals treated with one dose of PLGA-OVA and 3 dosis OVA-sol than those obtained from non-desensitised controls (IL-10= PLGA-OVA 1039 ± 91.7 pg/ml vs control PLGA 471 ± 28 pg/ml, p< 0.01; OVA-sol 932 ± 82.5 pg/ml vs control saline solution: 308 ± 68.66 p<0.01; INFγ=: PLGA-OVA 51,59±17.07 pg/ml vs control PLGA 12.77 ± 1.15 pg/ml p<0.01, OVA-sol 42.66 ± 3.0 pg/ml vs control saline 10.41 ± 5.2 pg/ml p< 0.01).  Our results suggest that among the different SITs evaluated, PLGA-OVA is the one that best showed an increase in the asymmetric IgG molecules, which would block the allergen, and an effective deviation of the immune response. Furthermore, the increase in the proportion of asymmetric antibodies would be of importance when designing new vaccination strategies for allergy.