Differential recognition of recombinant Phl p 5 isoallergens by Phl p 5-specific T cells.
BACKGROUND
At present, recombinant allergens are considered for the diagnosis and treatment of atopic allergies. To evaluate the theoretical impact of isoallergen variation on the selection of isoallergens for specific allergy vaccination, we characterized the T-cell response of allergic patients to the Phleum pratense major allergen, Phl p 5, and five of its recombinant isoallergens.


METHODS
Phl p 5-specific T cell lines (TCLs) were isolated from the peripheral blood of 3 allergic rhinitis patients, and their reactivity patterns were studied in detail.


RESULTS
The TCLs were highly crossreactive with related grasses. The crossreactivity with Poa pratensis was more extensive than with Lolium perenne, directly reflecting the sequence identity between Phl p 5, Poa p 5, and Lol p 5. The TCLs produced IFN-gamma and IL-4 simultaneously, resembling a Th0-like cytokine production profile. Interestingly, when T cell clones were tested with natural Phl p 5 and five rPhl p 5 isoallergens, a differential recognition pattern was found. One of the TCLs exclusively reacted with Phl p 5b, another reacted with all isoforms tested, and the third reacted strongly with native purified Phl p 5, but only weakly with all five recombinant isoallergens.


CONCLUSIONS
These results indicate that Phl p 5-specific T cells are highly heterogeneous, and that they differentially recognize isoallergens. This indicates that when recombinant Phl p 5 is considered for allergy vaccination, a mixture of isoallergens representing the different isoallergen groups may clinically prove to be more effective than single isoallergens.
van Neerven
R
R
ALK ABELLO Group, Horsholm, Denmark. jvn.dk@chr-hansen.com
Wissenbach
M
M
Ipsen
H
H
Bufe
A
A
Arnved
J
J
Würtzen
P A
PA
D000485:Allergens; D000595:Amino Acid Sequence; D017951:Antigen Presentation; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D016056:Immunodominant Epitopes; D007519:Isoantigens / Q000276:immunology; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology*; D011058:Pollen; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012260:Ribonucleases / Q000235:genetics / Q000276:immunology*; D016415:Sequence Alignment; D013601:T-Lymphocytes / Q000276:immunology*
D000485:Allergens; D016056:Immunodominant Epitopes; D007519:Isoantigens; D010940:Plant Proteins; D011994:Recombinant Proteins; C102306:Phl p Vb protein, Phleum pratense; D012260:Ribonucleases