title: Potential therapeutic recombinant proteins comprised of peptides containing recombined T cell epitopes.
abstract: The complete primary structure of Fel d I2 has been determined and shown to be comprised of two separate polypeptide chains (designated chain 1 and 2). Overlapping peptides covering the entire sequence of both chains of Fel d I have been used to map the major areas of human T cell reactivity. The present study describes three non-contiguous T cell reactive regions of < 30 aa in length that were assembled in all six possible configurations using PCR and recombinant DNA methods. These six recombinant proteins comprised of defined non-contiguous T cell epitope regions artificially combined into single polypeptide chains have been expressed in E. coli, highly purified, and examined for their ability to bind to human cat-allergic IgE and for human T cell reactivity. Several of these recombined T cell epitope-containing polypeptides exhibit markedly reduced IgE binding as compared to the native Fel d I. Importantly, the human T cell reactivity to individual T cell epitope-containing regions is maintained even though each was placed in an unnatural position as compared to the native molecule. In addition, T cell responses to potential junctional epitopes were not detected. It was also demonstrated in mice that s.c. injection of T cell epitope-containing polypeptides inhibits the T cell response to the individual peptides upon subsequent challenge in vitro. Thus, these recombined T cell epitope-containing polypeptides, which harbor multiple T cell reactive regions but have significantly reduced reactivity with allergic human IgE, constitute a novel potential approach for desensitization to important allergens.
authors.affiliation: ImmuLogic Pharmaceutical Corporation, Waltham, MA 02154.
authors.forename: B L
authors.initials: BL
authors.lastname: Rogers
authors.forename: J F
authors.initials: JF
authors.lastname: Bond
authors.forename: S J
authors.initials: SJ
authors.lastname: Craig
authors.forename: A K
authors.initials: AK
authors.lastname: Nault
authors.forename: D B
authors.initials: DB
authors.lastname: Segal
authors.forename: J P
authors.initials: JP
authors.lastname: Morgenstern
authors.forename: M S
authors.initials: MS
authors.lastname: Chen
authors.forename: C B
authors.initials: CB
authors.lastname: Bizinkauskas
authors.forename: C M
authors.initials: CM
authors.lastname: Counsell
authors.forename: A M
authors.initials: AM
authors.lastname: Lussier
mesh_terms: D000485:Allergens / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002415:Cats / Q000276:immunology; D003888:Desensitization, Immunologic / Q000379:methods*; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000485:Allergens; D000939:Epitopes; D006023:Glycoproteins; D007376:Interleukin-2; D011994:Recombinant Proteins; D007073:Immunoglobulin E; C059296:Fel d 1 protein, Felis domesticus