Development and preliminary clinical evaluation of a peptide immunotherapy vaccine for cat allergy

J Allergy Clin Immunol. 2011 Jan;127(1):89-97, 97.e1-14. doi: 10.1016/j.jaci.2010.11.029.

Abstract

Background: Allergic sensitization to cat allergens is common and represents a major risk factor for asthma. Specific immunotherapy (SIT) is effective but cumbersome and associated with IgE-dependent adverse events. Immunotherapy targeting allergen-specific T cells, with synthetic peptides representing T-cell epitopes, might improve safety and reduce the duration of treatment.

Objective: We sought to define major T-cell epitopes of Fel d 1 for peptide immunotherapy, generate a peptide vaccine, and evaluate its safety and tolerability in subjects with cat allergy.

Methods: We determined the binding affinities of Fel d 1 peptides for 10 commonly expressed HLA-DR molecules. Functionally immunodominant peptides were identified by means of proliferation and cytokine secretion. Histamine-releasing activity was assessed, and a peptide vaccine was formulated. Safety and tolerability were evaluated in a dose-ranging phase IIa clinical trial.

Results: MHC-binding sequences were identified throughout Fel d 1. Some regions contained multiple overlapping T-cell epitopes that bound multiple MHC molecules. Immunodominant sequences were identified on the basis of proliferative and cytokine (IFN-γ, IL-10, and IL-13) responses. Cat allergen extract, but not peptides, induced histamine release in blood basophils. A single administration of peptide vaccine was safe and well tolerated. The dose of vaccine resulting in the greatest inhibition of the late-phase skin response to intradermal whole allergen challenge was 3 nmol.

Conclusions: Fel d 1 contains multiple overlapping MHC-binding motifs. A peptide vaccine comprising the immunodominant regions of the allergen was safe and well tolerated when given to subjects with cat allergy as a single dose. The dose of vaccine resulting in the greatest reduction in late-phase skin response was defined for future clinical development.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cats
  • Double-Blind Method
  • Epitopes, T-Lymphocyte / immunology
  • Glycoproteins / immunology
  • Glycoproteins / therapeutic use
  • HLA-DR Antigens
  • Humans
  • Hypersensitivity / immunology
  • Hypersensitivity / prevention & control*
  • Immunodominant Epitopes
  • Immunotherapy / methods*
  • Molecular Sequence Data
  • Vaccines, Subunit / immunology*
  • Vaccines, Subunit / therapeutic use

Substances

  • Epitopes, T-Lymphocyte
  • Glycoproteins
  • HLA-DR Antigens
  • Immunodominant Epitopes
  • Vaccines, Subunit
  • Fel d 1 protein, Felis domesticus