The present invention relates to the discovery, identification and characterization of nucleic acids that 
encode a 
novel protein differentially expressed within the TH2 
cell subpopulation (hereinafter referred to as STIF). The invention encompasses STIF nucleotides, host 
cell expression systems, STIF proteins, fusion proteins, polypeptides and peptides, antibodies to the STIF 
protein, transgenic animals that express a STIF 
transgene, or recombinant knock-out animals that do not express the STIF 
protein, and compounds that modulate STIF 
gene expression or STIF activity that can be used for diagnosis, 
drug screening, 
clinical trial monitoring, and / or used to treat STIF based disorders, such as proliferative disorders and T-
lymphocyte-related disorders including, but not limited to, chronic inflammatory diseases and disorders, such as Crohn's 
disease, reactive 
arthritis, including 
Lyme disease, 
insulin-dependent diabetes, organ-specific 
autoimmunity, including 
multiple sclerosis, Hashimoto's 
thyroiditis and Grave's 
disease, 
contact dermatitis, 
psoriasis, 
graft rejection, 
graft versus host disease, 
sarcoidosis, atopic conditions, such as 
asthma and 
allergy, including allergic rhinitis, gastrointestinal allergies, including food allergies, 
eosinophilia, conjunctivitis, glomerular 
nephritis, certain 
pathogen susceptibilities such as helminthic (e.g., 
leishmaniasis) and certain viral infections, including HIV, and bacterial infections, including 
tuberculosis and lepromatous 
leprosy.