Non-allergenic antigen in allergic sensitization: responses to the mite ferritin heavy chain antigen by allergic and non-allergic subjects.
BACKGROUND
The majority of house dust mite proteins are non-allergenic. There is, however, no information on the type of immune responses produced to these proteins and if the responses are affected by allergic sensitization.


OBJECTIVE
To identify and produce a non-allergenic antigen of the house dust mite and compare antibody and T cell responses with the responses to allergens in sensitized and non-sensitized individuals.


RESULTS
Ferritin heavy chain was cloned from a cDNA library as a candidate non-allergen of the house dust mite. It bound IgG but not IgE in the sera of allergic and non-allergic subjects and induced high T cell proliferative responses that correlated highly with the responses to the major allergen Der p 2. The cytokine response to the non-allergen was characterized by the release of high levels of both Th1 and Th2 cytokines from the PBMC of both allergic and non-allergic subjects. In contrast, the response to Der p 2 showed the expected high level of Th2 cytokine release from the PBMC of allergic subjects, while the Th2 cytokine production from PBMC of non-allergic subjects was low and even lower than that induced by ferritin heavy chain. The levels of IFN-gamma release were similar for all groups. Der p 2 induced significantly more IL-10 than ferritin in the non-allergic group.


CONCLUSIONS
The T cell responses to a non-allergenic protein of the house dust mite were high and strongly correlated with the response to the major allergen. The non-allergenic protein induced high levels of Th1 and Th2 cytokine in both allergic and non-allergic subjects, while the allergen induced high levels of Th2 cytokine in allergic subjects and low levels in non-allergic subjects. The responses to the allergen were thus independently up- and down-regulated with no evidence of bystander regulation.
Epton
M J
MJ
Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, Perth, Australia.
Smith
W
W
Hales
B J
BJ
Hazell
L
L
Thompson
P J
PJ
Thomas
W R
WR
D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000235:genetics / Q000276:immunology*; D060829:Arthropod Proteins; D001483:Base Sequence; D016022:Case-Control Studies; D016207:Cytokines / Q000276:immunology; D005293:Ferritins / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013601:T-Lymphocytes / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D016207:Cytokines; C451163:Dermatophagoides pteronyssinus antigen p 2; D007143:Immunoglobulin Heavy Chains; D005293:Ferritins