Antiallergic Effect of Anti–Siglec-F through Reduction of Eosinophilic Inflammation in Murine Allergic Rhinitis

Abstract

Sialic acid-binding Ig-like lectin-F (Siglec-F) in mice and its functional paralog Siglec-8 in humans are transmembrane receptors that play a role in the apoptosis of eosinophils. We aimed to evaluate the therapeutic potential of anti-Siglec-F antibodies in a murine model of allergic rhinitis. Twenty-eight BALB/c mice were used. In group A (control group, n = 7), mice were sensitized and challenged with saline. In group B (ovalbumin [OVA] challenge group, n = 7), OVA was used for i.p. sensitization and intranasal challenge. Mice in group C (control IgG group, n = 7) or those in group D (anti-Siglec-F group, n = 7) had been given rabbit control IgG or anti-Siglec-F antibody injections, respectively. We assessed the number of nose-scratching events; serum total/OVA-specific IgE; the number of eosinophils, neutrophils, and lymphocytes in bronchoalveolar lavage (BAL) fluid; histopathological changes in nasal cavity tissues; and the levels of IL-4, IL-5, and IL-13 in BAL fluid. Mice in group D had significantly less nose scratching. Serum total and OVA-specific IgE were not significantly changed. The number of eosinophils in BAL fluid and in the lamina propria of the nasal cavity mucosa was significantly decreased with anti-Siglec-F antibody treatment. The levels of Th2 cytokines such as IL-4, IL-5, and IL-13 were also significantly decreased with anti-Siglec-F antibody treatment. Anti-Siglec-F antibody has beneficial effects in a mouse model of experimental allergic rhinitis.