Characterization of human memory CD4(+) T-cell responses to the dog allergen Can f 4.

Background: The recently identified dog lipocalin allergen Can f 4 is an important respiratory allergen.

Objective: We sought to comprehensively characterize the memory CD4(+) T-cell responses of allergic and nonallergic subjects to Can f 4.

Methods: Can f 4-specific CD4(+)CD45RO(+) T-cell lines (TCLs) from allergic and healthy subjects were established and characterized by their functional and phenotypic properties.

Human CD4+ T cell responses to the dog major allergen Can f 1 and its human homologue tear lipocalin resemble each other.

Lipocalin allergens form a notable group of proteins, as they contain most of the significant respiratory allergens from mammals. The basis for the allergenic capacity of allergens in the lipocalin family, that is, the development of T-helper type 2 immunity against them, is still unresolved. As immunogenicity has been proposed to be a decisive feature of allergens, the purpose of this work was to examine human CD4+ T cell responses to the major dog allergen Can f 1 and to compare them with those to its human homologue, tear lipocalin (TL).

Immunotherapeutic potential of the immunodominant T-cell epitope of lipocalin allergen Bos d 2 and its analogues.

Lipocalin allergens, which contain most of the important animal-derived respiratory sensitizers, induce T helper type 2 (Th2) deviation, but the reasons for this are not clear. To explore the prospects for peptide-based allergen immunotherapy and to elucidate the characteristics of the immunodominant epitope of Bos d 2, BALB/c mice were immunized with a peptide containing the epitope, peptides containing its analogues, peptides from the corresponding regions of other lipocalin proteins, and peptides with a homologous sequence. We observed that murine spleen cells recognized the immunodominant epitope of Bos d 2, p127-142, in almost the same way as human Bos d 2-specific T cells did.

Use of multiple peptides containing T cell epitopes is a feasible approach for peptide-based immunotherapy in Can f 1 allergy.

We have previously shown that the major dog allergen Can f 1 contains seven T cell epitope regions, none of which was preferentially recognized. To identify the immune characteristics of Can f 1 epitopes and to verify their suitability for peptide-based allergen immunotherapy, short-term T cell lines were generated with epitope-containing peptides from peripheral blood mononuclear cells of Can f 1 skinprick test-positive allergic and healthy control subjects. The lines were examined for their proliferative capacity and cytokine production upon stimulation with the allergen peptide, a homologous peptide from human tear lipocalin (TL) and Can f 1 and TL proteins.