目的 研究不同灭菌次数处理后磷酸铝佐剂的理化性质，并评估不同灭菌次数处理的磷酸铝佐剂对6A型肺炎球菌多糖破伤风类毒素（tetanus toxoid，TT）结合物（6A-TT）在小鼠中免疫原性的影响。方法 将自制磷酸铝佐剂分别灭菌1、2和3次，考察其粒径大小及分布、pH、等电点、游离磷酸根离子含量、磷铝摩尔比和蛋白吸附率。通过免疫CD1小鼠，评估经不同灭菌次数处理的磷酸铝佐剂与6A-TT配伍后对实验动物产生的特异性抗体滴度的影响。结果 磷酸铝佐剂灭菌1、2和3次后的50%分布粒径（Dv50）分别为5.04、5.22和5.12 μm，Dv90分别为9.20、9.87和10.60 μm，pH分别为4.6、4.3和4.3，等电点分别为5.48、5.36和5.29，游离磷酸根离子含量分别为4.12%、4.79%和4.86%，磷铝摩尔比分别为1.012、0.972和0.944，对TT的吸附率分别为92.7%、87.8%和85.7%，对6A-TT的吸附率分别为93.8%、91.6%和90.1%。磷酸铝佐剂在灭菌1、2和3次后分别吸附6A-TT，均能诱导小鼠产生抗体，其几何平均滴度分别为1 213、985和1 056。结论 灭菌次数的增加会导致磷酸铝佐剂的等电点和pH下降，游离磷酸根含量升高，磷铝摩尔比和蛋白吸附率降低，并可能影响6A-TT中抗原在小鼠体内的免疫原性。

Objective To investigate the physicochemical properties of aluminum phosphate adjuvants subjected to different numbers of autoclaving cycles and to evaluate the effect of aluminum phosphate adjuvant with varying autoclaving cycles on immunogenicity of type 6A pneumococcal polysaccharide-tetanus toxoid (TT) conjugate (6A-TT).Methods Self-prepared aluminum phosphate adjuvants were autoclaved 1, 2, and 3 times, respectively. The particle size and distribution, pH, isoelectric point, free phosphate content, phosphorus-to-aluminum molar ratio, and protein adsorption rate were examined. Additionally, the effect of aluminum phosphate adjuvants treated with different autoclaving cycles, when combined with 6A-TT, on the specific antibody titers in mice was assessed.Results After autoclaving 1, 2, and 3 times, the 50% particle distribution diameters (Dv50s) of aluminum phosphate adjuvant were 5.04, 5.22, and 5.12 μm, while Dv90s were 9.20, 9.87, and 10.60 μm, respectively. The pH values were 4.6, 4.3, and 4.3, while the isoelectric points were 5.48, 5.36, and 5.29, respectively. The free phosphate content were 4.12%, 4.79%, and 4.86%, and the phosphorus-to-aluminum molar ratios were 1.012, 0.972, and 0.944, respectively. The adsorption rates of aluminum adjuvant to TT were 92.7%, 87.8%, and 85.7%, and to 6A-TT were 93.8%, 91.6%, and 90.1%, respectively. The aluminum phosphate adjuvant, after autoclaving 1, 2, and 3 times, was able to adsorb 6A-TT and induce antibody production in mice, with geometric mean titers of 1 213, 985, and 1 056, respectively.Conclusions Increasing the number of autoclaving cycles leads to decrease in the isoelectric point and pH of the aluminum phosphate adjuvant, increase in free phosphate content, and reduction in the phosphorus-to-aluminum molar ratios and protein adsorption rate. It may also have an effect on the immunogenicity of 6A-TT pneumococcal polysaccharide antigen in mice.