Specific immune response to Phleum pratense plant profilin in atopic patients and control subjects.
BACKGROUND
Phleum pratense (Phl p) pollen is a known cause of allergic disease worldwide. Profilins have been identified as functional plant pan-allergens. The role of Phl p profilin in the specific immune response in sensitized Phl p patients is unknown.


METHODS
Skin prick test and specific serum IgE levels were performed in 26 patients allergic to Phl p and in 18 nonallergic control donors. Peripheral blood mononuclear cells were isolated from both groups and stimulated with crude extract or highly purified Phl p profilin, and the production of type I and type II cytokines was determined in patients and controls stimulated with specific and polyclonal stimulus. T-cell lines specific to Phl p profilin were established from PBMCs and cross-reactivity with another highly purified profilin from Parietaria judaica (Pj) was evaluated.


RESULTS
Patients allergic to Phl p profilin showed increased T-cell-proliferative responses to this profilin compared with control subjects. The production of IL-4 and IFN-gamma in response to the specific stimulus was undetectable. However, the production of IL-4 and IFN-gamma in response to a polyclonal stimulus (PHA) was measurable and different for atopic patients and control subjects: IL-4 was higher (p < 0.001) in allergic patients and IFN-gamma lower (although not significant) in controls. Neither the T-cell responses nor the production of IL-4 in response to a polyclonal stimulus (PHA) correlated with the individual degree of cutaneous response to Phl p profilin or to the levels of specific Phl p IgE. The T-cell lines tested did not show any cross-reactivity with Pj profilin.


CONCLUSIONS
Phl p profilin is in part responsible for the T-cell mediated immunological response in patients allergic to Phl p. The response is very specific since Phl p profilin specific T-cell lines did not show cross-reactivity with a highly homologous profilin from Parietaria judaica (Pj). The lack of correlation between the proliferative T-cell response and polyclonal IL-4 production with allergen-specific serum IgE and SPT probably indicates that some of the responding T-cells may be involved in immune reactions other than the support of IgE production.
Benítez
D
D
Servei Immunologia, IDIBAPS, Hospital Clínic Barcelona.
García-Ortega
P
P
Picado
C
C
Milà
J
J
Vives
J
J
Martínez
J
J
Vilella
R
R
D000328:Adult; D000485:Allergens / Q000276:immunology*; D002460:Cell Line; D003285:Contractile Proteins; D003429:Cross Reactions; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000209:etiology / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008840:Microfilament Proteins / Q000276:immunology*; D010940:Plant Proteins / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D051304:Profilins; D006255:Rhinitis, Allergic, Seasonal / Q000209:etiology / Q000276:immunology*; D012882:Skin Tests; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism
D000485:Allergens; D003285:Contractile Proteins; D008840:Microfilament Proteins; D010940:Plant Proteins; D051304:Profilins; D015847:Interleukin-4; D007073:Immunoglobulin E; D007371:Interferon-gamma