Heat shock cognate 70 protein like-2 protein in camphor pollen is one of the major culprits of asthma.

Abstract

In recent decades, Cinnamomum camphora have gradually become the main street trees in Shanghai. This study aims to investigate the allergenicity of camphor pollen. A total of 194 serum samples from patients with respiratory allergy were collected and analyzed. Through protein profile identification and bioinformatics analysis, we hypothesized that heat shock cognate protein 2-like protein (HSC70L2) is the major potential allergenic protein in camphor pollen. Recombinant HSC70L2 (rHSC70L2) was expressed and purified, and a mouse model of camphor pollen allergy was established by subcutaneous injection of total camphor pollen protein extract (CPPE) and rHSC70L2. Specific IgE was found in the serum of 5 patients in response to camphor pollen and three positive bands were identified by Western blotting. Enzyme-linked immunosorbent assay (ELISA), Immune dot blot and Western blot experiments confirmed that CPPE and rHSC70L2 can cause allergies in mice. Moreover, rHSC70L2 induces polarization of peripheral blood CD4+ T cells to Th2 cells in patients with respiratory allergies and mice with camphor pollen allergy. Finally, we predicted the T cell epitope of the HSC70L2 protein, and through the mouse spleen T cell stimulation experiment, we found that the 295EGIDFYSTITRARFE309 peptide induced T cells differentiation to Th2 and macrophages differentiation to the alternatively activated (M2) state. Moreover, 295EGIDFYSTITRARFE309 peptide increased the serum IgE levels in mice. The identification of HSC70L2 protein can provide novel diagnostic and therapeutic targets for allergies caused by camphor pollen.