IgA response in serum and gut secretion in sensitized mice fed with the dust mite Dermatophagoides pteronyssinus extract

Abstract

Induced oral tolerance to mucosal-exposed antigens in immunized animals is of particular interest for the development of immunotherapeutic approaches to human allergic diseases. This is a unique feature of mucosal surfaces which represent the main contact interface with the external environment. However, the influence of oral tolerance on specific and natural polyreactive IgA antibodies, the major defense mechanism of the mucosa, is unknown. We have shown that oral administration of an extract of the dust mite Dermatophagoides pteronyssinus (Dp) to primed mice caused down-regulation of IgE responses and an increase in tumor growth factor-ß secretion. In the present study, we observed that primed inbred female A/Sn mice (8 to 10 weeks old) fed by gavage a total weight of 1.0-mg Dp extract on the 6th, 7th and 8th days post-immunization presented normal secretion of IL-4 and IL-10 in gut-associated lymphoid tissue and a decreased production of interferon gamma induced by Dp in the draining lymph nodes (13,340 ± 3,519 vs 29,280 ± 2,971 pg/ml). Mice fed the Dp extract also showed higher levels of serum anti-Dp IgA antibodies and an increase of IgA-secreting cells in mesenteric lymph nodes (N = 10), reflecting an increase in total fecal IgA antibodies (N = 10). The levels of secretory anti-Dp IgA antibodies increased after re-immunization regardless of Dp extract feeding. Oral tolerance did not interfere with serum or secretory IgA antibody reactivity related to self and non-self antigens. These results suggest that induction of oral tolerance to a Dp extract in sensitized mice triggered different regulatory mechanisms which inhibited the IgE response and stimulated systemic and secretory IgA responses, preserving the natural polyreactive IgA antibody production.

Evaluation of Bioadhesive Capacity and Immunoadjuvant Properties of Vitamin B12-Gantrez Nanoparticles

“…Faecal samples were collected and analysed as described previously (17). Pooled fresh pelleted faeces from each group of mice were put into microtubes on 0, 1, 2, 4, 6 weeks post administration and weighed.…”

Phage Display–Derived Ligand for Mucosal Transcytotic Receptor GP-2 Promotes Antigen Delivery to M Cells and Induces Antigen-Specific Immune Response

“…15 Five days after the last immunization, serum and fecal extracts were collected to monitor EGFP-specific systemic IgG and mucosal IgA as described by Hackett et al 16 Since IgA in fecal extracts is rapidly degraded by the proteases from enteric bacteria, 1 mM phenylmethyl sulfonyl fluoride (PMFS) protease inhibitor was included in the extraction cocktail. 17 Ab titers were expressed as the reciprocal log2 of the highest sample dilutions that gave an OD 450 of 0.08, which was the value of the PBS blank.…”