An immune response study of oakmoss absolute and its constituents atranol and chloroatranol.

BACKGROUND: Atranol and chloroatranol are the main allergens of oakmoss absolute. However, the immune responses induced by these substances are poorly characterized. OBJECTIVES: To characterize immune responses induced by atranol, chloroatranol and oakmoss absolute in mice. METHODS: Mice were sensitized and challenged with various concentrations of atranol, chloroatranol, and oakmoss absolute. The immune responses were analysed as B cell infiltration, T cell proliferation in the draining lymph nodes, and expression of interleukin (IL)-18, IL-1ß and tumour necrosis factor-α in skin. The cytotoxicity of atranol and chloroatranol against keratinocytes was determined. RESULTS: Sensitization experiments showed that atranol, chloroatranol and oakmoss induced sensitization when applied in high concentrations. Challenge experiments showed that even low concentrations of atranol and chloroatranol induced sensitization. In parallel, atranol and chloroatranol elicited challenge reactions following sensitization with oakmoss. The magnitude of the immune response to the three allergens increased in the following order: atranol, chloroatranol, and oakmoss. The expression of proinflammatory cytokines was induced by chloroatranol and oakmoss, but not by atranol. Chloroatranol was found to be more cytotoxic than atranol against keratinocytes. CONCLUSIONS: Atranol and chloroatranol can elicit both sensitization and challenge reactions, but the mixture of allergens in oakmoss absolute is more potent than atranol and chloroatranol alone.

Enhanced sensitization and elicitation responses caused by mixtures of common fragrance allergens.

BACKGROUND: Perfumes are complex mixtures composed of many fragrance ingredients, many of which are known to be only weak allergens when tested individually. It is therefore surprising that fragrance contact allergy is one of the most common forms of contact allergy. OBJECTIVES: To investigate whether mixing different fragrance allergens leads to increased sensitization potency, and to examine the difference in the challenge response to one chemical in mice sensitized either with the mixture of allergens or with only the relevant allergen. METHODS: CBA mice were sensitized with three different concentrations of three fragrance allergens alone or as a mixture. The sensitization and elicitation responses were measured by ear thickness plus infiltration of B and T cells and T cell proliferation in the draining lymph nodes. RESULTS: We found a dose-dependent sensitization response for each of the allergens. An increased response was seen when the allergens were mixed. A stronger challenge response to cinnamal was seen in mice sensitized with the allergen mixture than in mice sensitized with cinnamal alone. CONCLUSIONS: Our findings suggest that mixtures of allergens increase the primary response that potentiates the generation of memory T cells in response to the specific allergen. Thus, allergen mixtures enhance both induction and elicitation of contact allergy.

Polymorphisms of the T cell receptor CD3delta and CD3epsilon chains affect anti-CD3 antibody binding and T cell activation.

T cell receptor (TCR) structure and function have been thoroughly studied for decades. Production and analyses of knock-out and knock-in mice with mutations in the CD3 chains have contributed significantly to these studies. The generation of such gene-modified mice relies on the availability of suitable embryonic stem (ES) cell lines. Traditionally, ES cell lines from the 129 mouse strains have been used followed by backcrossing to the C57BL/6 strain. In the present study, we demonstrate the existence of polymorphisms in the CD3 genes from mice of the 129 and C57BL/6 strains. These polymorphisms result in amino acid substitutions in the ectodomains of both the CD3delta and CD3epsilon chains in 129 mice compared to C57BL/6 mice. The amino acid substitutions do not change the stoichiometry or surface expression level of the TCR complex in 129 T cells but cause reduced anti-CD3 antibody binding to 129 T cells. Further, when stimulated with mitogenic anti-CD3 antibodies, T cells from the 129 strains show reduced expression of the activation marker CD69, Ca(2+) flux, IL-2 production and proliferative responses compared to C57BL/6 T cells. These findings demonstrate that polymorphisms of the CD3delta and epsilon ectodomains exist in mice, and that some of these polymorphisms lead to amino acid substitutions which cause structural changes and affect anti-CD3 antibody binding. Thus, functional T cell studies should be interpreted with caution when anti-CD3 antibodies are used for stimulation of T cells derived from gene-modified mice originating from 129 ES cell lines.