Evidence of immunostimulating lipoprotein existing in the natural lipoteichoic acid fraction.

Lipoteichoic acid (LTA) is a cell surface glycoconjugate of gram-positive bacteria and is reported to activate the innate immune system. We previously reported that purified LTA obtained from Enterococcus hirae has no immunostimulating activity, but a subfraction (Eh-AF) in an LTA fraction possesses activity. In this study, we established a mouse monoclonal antibody neutralizing the activity of Eh-AF and investigated its inhibitory effects. Monoclonal antibody (MAbEh1) was established by the immunization of BALB/c mice with Eh-AF, followed by hybridoma screening based on its inhibitory effect for the production of interleukin-6 (IL-6) induced by Eh-AF. MAbEh1 neutralized the production of IL-6 by LTA fraction from not only E. hirae but also Staphylococcus aureus, while it failed to block that of lipopolysaccharide, suggesting that the antibody recognized a common active structure(s) in LTA fractions. Synthetic glycolipids in these LTAs did not induce cytokine production, at least in our system. Interestingly, the antibody was found to inhibit the activity of immunostimulating synthetic lipopeptides, Pam(3)CSK(4) and FSL-1. These results suggest that MAbEh1 neutralizes the activity of lipoprotein-like compounds which is responsible for the activity of the LTA fraction of E. hirae and S. aureus.

Efficacy of levocabastine hydrochloride ophthalmic suspension in the conjunctival allergen challenge test in Japanese subjects with seasonal allergic conjunctivitis.

BACKGROUND: This study was conducted to investigate the efficacy and safety of 0.025% levocabastine hydrochloride in Japanese subjects with seasonal allergic conjunctivitis and its duration of action using the conjunctival allergen challenge (CAC) test. METHODS: Twenty-four asymptomatic subjects were randomized to instill 0.025% levocabastine ophthalmic suspension in one eye and vehicle in the other eye 10 minutes before the CAC test. Signs and symptoms of allergic conjunctivitis were scored 10, 15, and 25 minutes after the CAC test. The duration of drug effects was also evaluated by allergen rechallenge 4 hours after levocabastine administration. The itching score for each eye as the primary efficacy endpoint was assessed 15 minutes after the CAC test using a 5-point scale. RESULTS: The mean itching score in the levocabastine-treated group was 0.08 +/- 0.06, which was significantly lower than the mean score of 1.98 +/- 0.16 in the vehicle group (P < 0.0001). The redness and chemosis of the conjunctiva were also improved significantly compared with the vehicle group. Levocabastine showed prolonged efficacy in inhibiting itching (0.42 +/- 0.12 vs 0.94 +/- 0.17, P < 0.0002) and redness (1.04 +/- 0.18 vs 1.42 +/- 0.22, P < 0.01) of the conjunctiva upon the rechallenge test. No significant topical or systemic adverse safety findings were observed in the levocabastine group. CONCLUSIONS: The results indicate that 0.025% levocabastine ophthalmic suspension is effective and safe in the treatment of allergic conjunctivitis with a duration of action of at least 4 h.