Analysis of the CD4⁺ T cell responses to house dust mite allergoid

Abstract

The reduced stimulatory potential of HDM-GA results mainly from a loss of certain Th cell epitopes, rather than impaired allergen uptake and presentation, or induction of suppressive factors. Varying frequencies of allergoid-nonreactive HDM-specific Th cells may result in differential responses of individual patients to immunotherapy.

Chemical Modification of Birch Allergen Extract Leads to a Reduction in Allergenicity as well as Immunogenicity

“…4). This suggests that the chemical modifications of the allergen hamper the uptake or processing mechanisms that lead to peptide presentation regardless of the type of APC involved in the process, which is supporting the data from Kalinski et al [16]. …”

“…3) [16,17,18], it has been speculated that DC or macrophages present in tissue rather than monocytes or B cells obtained from peripheral blood are the relevant APC to use in the T cell assay system [18, 19]. This issue was put forward by Kahlert et al [18, 19], who initially reported that T cell responses to grass allergoids were markedly reduced when compared to intact allergens.…”

“…On the other hand, in vitro T cell responses to allergoids have been reported to be markedly reduced compared to responses to intact allergens [16,17,18], even though other reports seem to suggest that this mainly depended on the type of APC used [18, 19]. …”

“…Later, the same group reported that recognition of allergoids by T cell clones was enhanced when DC were used as APC. However, Kalinski et al [16], working with mite allergens, reported that mite allergen-specific T cell clones responded equally well whether PBMC or DC were used as APC and concluded that a selective loss of individual T cell epitopes was leading to a reduction in T cell activation. In the present work with birch allergens, similar responses to the individual allergen preparations were found when T cell lines from 4 birch-allergic patients were activated with allergen and allergoid preparations using PBMC or DC as APC (fig.…”

Characterization of Modified Allergen Extracts by in vitro β-Hexosaminidase Release from Rat Basophils

“…The higher the molecular weight, the lower the risk of side effects [16]. Allergoids have been compared with native allergens in in vitro studies, showing that the inter- and intramolecular bridging only slightly decreases the availability of T-cell epitopes [17, 18], but affects the way proteins are presented to the immune system. Allergoids are preferably presented to T cells by professional antigen-presenting cells and less by B cells such as native allergens [19].…”