May cause loosening of the cell walls. Expressed in pollen (at protein level) (PubMed:18817975, PubMed:21231976, PubMed:20962534, PubMed:22832594, PubMed:25612605). Glycosylated. Causes an allergic reaction in human. Binds to IgE of patients allergic to the pollen of grasses (PubMed:18817975, PubMed:21231976, PubMed:20962534, PubMed:22832594, PubMed:25612605). Natural protein binds to IgE in all 21 patients tested strongly allergic to Bahia grass pollen (BaGP). Recombinant protein binds to IgE in 85% of the 55 BaGP-allergic patients tested. Lack of glycosylation does not affect IgE-binding activity (PubMed:18817975). Natural protein binds to IgE in 91% of the 51 BaGP-allergic patients tested (PubMed:20962534). Natural protein reacts with monoclonal antibody against pollen allergen Lol p 1 (PubMed:18817975 PubMed:21231976, PubMed:20962534, PubMed:25612605). Both natural and recombinant protein can up-regulate CD63 expression on the surface of patients basophils (PubMed:18817975 PubMed:21231976). IgE of patients allergic to this protein cross-reacts with pollen allergens Lol p 1 and Cyn d 1 (PubMed:21231976, PubMed:22832594). At least one of the three immunodominant T cell epitopes evoke peripheral blood mononuclear cell (PBMC) proliferation in 83% of the 18 BaGP-allergic patients tested. T cell epitopes can also induce secretion of cytokines IL-4, IL-5, IL-10, IFN-gamma and TNF-alpha in BaGP-allergic patients, but do not bind IgE (PubMed:22832594). This protein has potential use in diagnosis and specific immunotherapy (SIT) of grass pollen allergy for patients living in a subtropical climate (PubMed:18817975, PubMed:21231976, PubMed:20962534, PubMed:25612605). The diagnostic sensitivity and specificity is 92.4% and 93.1%, respectively, for the detection of Bahia grass pollen (BaGP) allergy in patients that have sensitivity level of 0.23 kU/l of IgE for this protein (PubMed:25612605). The immunodominant T cell epitopes may be suitable for safe SIT for individuals with severe allergic symptoms to BaGP (PubMed:22832594). Belongs to the expansin family. Expansin B subfamily.