Fig. 3.

PMX-53 inhibits C5a-induced responses in HMC-1 and RBL-2H3 cells expressing CD88. A, HMC-1 cells were incubated with Indo-1AM and stimulated sequentially with 10 nM C5a and 10 nM C3a, and intracellular Ca²⁺ mobilization was determined. Cells were exposed to 10 nM PMX-53 (B), PMX-53C (C), or PMX-53S (D) 100 s before stimulation with C5a and C3a, and Ca²⁺ mobilization was determined. E, RBL-2H3 cells stably expressing CD88 were pretreated with vehicle or 10 nM PMX-53 and exposed to 1 nM C5a, and percentage degranulation (β-hexosaminidase release) was determined. Data shown are representative of three similar experiments. Data are mean ± S.E.M. of n = 3. Statistical significance was determined by two-way ANOVA with Bonferroni's post test. *, p < 0.05.