Abstract: Peptide compositions comprising a dimeric peptide which combines two peptide monomers, each independently comprising the amino acid sequence: Asp-X1-X2-Asn-Tyr-Ile-Thr-X3 wherein: X1 is selected from the group consisting of Cys and a Cys derivative; X2 is selected from the group consisting of Cys and a Cys derivative; and X3 is selected from the group consisting of Arg and Glu-Leu-Arg, provided that at least one of X1 and X2 is Cys, whereby a mol percentage of the dimeric peptide in the composition is at least 50 mol percents, or at least 99 mol percents, are disclosed. Further disclosed are processes of preparing such peptide compositions and uses thereof in the treatment of allergic disorders.

Abstract: Peptides corresponding partially to positions 55-64 of the sequence of the complement component peptide C3a are capable of preventing and treating mast cell- and basophil-mediated disorders by inhibiting IgE- or IgG-mediated triggering and/or by inhibiting the Fc?RI- and/or Fc?R-induced secretory response, while obviating the anaphylatoxic response. These peptides are useful for prevention and/or treatment of allergic disorders where mucosal-type and/or serosal-type mast cells and/or basophils are involved such as asthma, allergic dermatosis, and gastrointestinal allergies.

Abstract: Peptides corresponding partially or entirely to positions 50-77 of the sequence of the complement-derived peptide C3a and analogs thereof are capable of inhibiting IgE-mediated triggering and/or the Fc&egr;RI-induced secretory response of mucosal mast cells. These peptides are useful for prevention and/or treatment of allergic disorders caused by IgE mediated (Type I) hypersensitivity where mucosal-type mast cells are involved, such as hay fever, asthma, some cases of urticaria or allergic conjunctivitis.

Abstract: An isolated DNA sequence encoding a mammalian mast cell function-associated antigen (MAFA) is provided. A soluble derivative of the MAFA is obtained by culturing a host cell transformed by a recombinant expression vector comprising a sequence of said DNA encoding a form of soluble MAFA, and may be used for screening potential ligands of the MAFA. The ligands, alone or in combination with the MAFA, may be used in pharmaceutical compositions for the prevention of inflammatory and allergic reactions.

Abstract: As assay for the measurement of direct binding of a peptide that is a T-cell epitope to gene products of the major histocompatibility complex (MHC), classes I and II, on the surface of intact living antigen-presenting cells, is provided. The assay comprises incubating the labelled peptide with the cells, and monitoring the extent of binding by the addition of a probe that reacts with the ligand used to label the peptide. The assay is suitable for autoimmune diseases and other immunological disorders. Peptides having a sequence corresponding to a stretch of the sequence of the antigen relevant to an immunological disorder, or modifications thereof, which bind to gene products of MHC, but do not stimulate T-cells, are also useful for the treatment of said disorders.

Abstract: Substantially pure cromolyn binding protein is prepared by means of affinity chromatography of cromolyn derivatives bound to insoluble matrices. Aminocromolyn is prepared by a six-step synthesis and amine derivatives thereof are prepared by conventional means. Obtaining a compound having an amine group instead of the OH group at the 2-carbon of the propane link of cromolyn permits many kinds of reactions without interfering with the portion of the cromolyn molecule with causes its pharmacological activity. The cromolyn derivatives can be conjugated to proteins such as BSA by means of glutaraldehyde cross-linking and such conjugates can be covalently bound to agarose beads. Cromolyn binding protein can be isolated by passing lysates of RBL-2H3 cells through chromatographic columns packed with such beads. The cromolyn binding protein can be further purified by means of lectin-agarose columns.

Abstract: According to the present invention there is provided an essentially pure protein found in nature in mast cells and in basophiles, which protein is involved in the transfer of calcium into such cells. Such a protein has an isoelectric point of about 3.9 and a MW about 60,000.+-.2,000, and has an amino acid composition as herein defined. There are also provided processes for the preparation of such purified protein. Such protein is of use in blocking histamine release from cells.