Cat allergen peptide immunotherapy reduces CD4(+) T cell responses to cat allergen but does not alter suppression by CD4(+) CD25(+) T cells: a double-blind placebo-controlled study.
BACKGROUND
We have previously described both modification of allergen immunotherapy using peptide fragments, and reduced regulation of allergen stimulated T cells by CD4(+) CD25(+) T cells from allergic donors when compared with nonallergic controls. It has been suggested that allergen immunotherapy induces regulatory T cell activity: we hypothesized that allergen peptide immunotherapy might increase suppressive activity of CD4(+) CD25(+) T cells.


OBJECTIVE
To examine cat allergen-stimulated CD4 T cell responses and their suppression by CD4(+) CD25(+) T cells before and after cat allergen peptide immunotherapy in a double-blind placebo-controlled study.


METHODS
Peripheral blood was obtained and stored before and after peptide immunotherapy or placebo treatment. CD4(+) and CD4(+) CD25(+) were then isolated by immunomagnetic beads and cultured with allergen in vitro.


RESULTS
Comparing cells from blood taken before with that after peptide immunotherapy there was a significant reduction in both proliferation and IL-13 production by allergen-stimulated CD4+ T cells, whereas no change was seen after placebo. CD4(+) CD25(+) T cells suppressed both proliferation and IL-13 production by CD4(+) CD25(-) T cells before and after therapy but peptide therapy was not associated with any change in suppressive activity of these cells.


CONCLUSIONS
Allergen peptide immunotherapy alters T cell response to allergen through mechanisms other than changes in CD4(+) CD25(+) T cell suppression.
Smith
T R F
TR
Department of Allergy and Clinical Immunology, National Heart and Lung Institute and Leukocyte Biology Section, Biomedical Sciences Division, Faculty of Medicine, Imperial College London, UK.
Alexander
C
C
Kay
A B
AB
Larché
M
M
Robinson
D S
DS
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000276:immunology* / Q000628:therapy; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002415:Cats; D003888:Desensitization, Immunologic / Q000379:methods*; D004306:Dose-Response Relationship, Immunologic; D004311:Double-Blind Method; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D018793:Interleukin-13 / Q000276:immunology; D008875:Middle Aged; D010455:Peptides / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D006023:Glycoproteins; D018793:Interleukin-13; D010455:Peptides; D015375:Receptors, Interleukin-2; C059296:Fel d 1 protein, Felis domesticus