Unique and cross-reactive T cell epitope peptides of the major Bahia grass pollen allergen, Pas n 1.

Abstract

BACKGROUND:

Bahia grass pollen (BaGP) is a major cause of allergic rhinitis. Subcutaneous allergen-specific immunotherapy is effective for grass pollen allergy, but is unsuitable for patients with moderate to severe asthma due to the risk of anaphylaxis. T cell-reactive but IgE nonreactive peptides provide a safer treatment option. This study aimed to identify and characterize dominant CD4(+) T cell epitope peptides of the major BaGP allergen, Pas n 1.

METHODS:

Pas n 1-specific T cell lines generated from the peripheral blood of BaGP-allergic subjects were tested for proliferative and cytokine response to overlapping 20-mer Pas n 1 peptides. Cross-reactivity to homologous peptides from Lol p 1 and Cyn d 1 of Ryegrass and Bermuda grass pollen, respectively, was assessed using Pas n 1 peptide-specific T cell clones. MHC class II restriction of Pas n 1 peptide T cell recognition was determined by HLA blocking assays and peptide IgE reactivity tested by dot blotting.

RESULTS:

Three Pas n 1 peptides showed dominant T cell reactivity; 15 of 18 (83%) patients responded to one or more of these peptides. T cell clones specific for dominant Pas n 1 peptides showed evidence of species-specific T cell reactivity as well as cross-reactivity with other group 1 grass pollen allergens. The dominant Pas n 1 T cell epitope peptides showed HLA binding diversity and were non-IgE reactive.

CONCLUSIONS:

The immunodominant T cell-reactive Pas n 1 peptides are candidates for safe immunotherapy for individuals, including those with asthma, who are allergic to Bahia and possibly other grass pollens.

• Authors: Tamara Etto, Carmela de Boer, Sara Prickett, Leanne M Gardner, Astrid Voskamp, Janet M Davies, Robyn E O'Hehir, Jennifer M Rolland
• Journal: International archives of allergy and immunology (Int Arch Allergy Immunol) Vol. 159 Issue 4 Pg. 355-66 ( 2012) ISSN: 1423-0097 [Electronic] Switzerland
• PMID: 22832594 (Publication Type: Journal Article)
• Copyright: Copyright © 2012 S. Karger AG, Basel.

Chemical References

• Allergens
• Antigens, Plant
• Epitopes, T-Lymphocyte
• Oligopeptides
• Pas n 1 allergen, Bahia grass
• Plant Proteins
• Immunoglobulin E

Topics

• Adult
• Allergens (chemistry, immunology)
• Amino Acid Sequence
• Antigens, Plant (chemistry, immunology)
• Asthma (complications, drug therapy, immunology)
• CD4-Positive T-Lymphocytes (chemistry, immunology)
• Clone Cells
• Cross Reactions
• Cynodon (chemistry, immunology)
• Desensitization, Immunologic
• Epitopes, T-Lymphocyte (chemistry, immunology)
• Female
• Humans
• Immunoglobulin E (immunology)
• Lolium (chemistry, immunology)
• Male
• Middle Aged
• Molecular Sequence Data
• Oligopeptides (chemistry, immunology, therapeutic use)
• Paspalum (chemistry, immunology)
• Plant Proteins (chemistry, immunology)
• Pollen (chemistry, immunology)
• Rhinitis, Allergic, Seasonal (complications, drug therapy, immunology)