Kohler R B, Wheat L J, White A
J Clin Microbiol. 1980 Jul;12(1):39-43. doi: 10.1128/jcm.12.1.39-43.1980.
We assessed the ability of a solid-phase radioimmunoassay, modified to allow antigen detection in serum, to detect circulating antigens in granulocytopenic rabbits with Pseudomonas aeruginosa bacteremia. In vitro experiments with Pseudomonas lipopolysaccharide indicated that treatment of serum-lipopolysaccharide mixtures with heat, chloroform, or heparin improved the sensitivity for detecting lipopolysaccharide 8- to 16-fold. Chloroform treatment permitted antigen detection in serum or plasma of bacteremic rabbits in which antigen could be detected poorly or not at all in untreated specimens. However, chloroform-treated specimens occasionally caused dissolution of plastic tubes, resulting in nonspecific binding of 125I-labeled anti-Pseudomonas immunoglobulin G. Heating sera at 56 degree C for 30 min improved antigen detection both in both in lipopolysaccharide-serum mixtures and in bacteremic rabbits. Antigen was detected in the heated serum or plasma of 20% of 20 culture-positive granulocytopenic rabbits, none of 15 culture-negative granulocytopenic rabbits, and none of 38 normal rabbits. Antigen was detected in none of 15 rabbits with 2 to 300 colony-forming units of P. aeruginosa per ml of blood and in 4 of 5 rabbits with > 10(3) colony-forming units per ml. We conclude that circulating antigens are present in the blood of rabbits with high-level P. aeruginosa bacteremia and that these antigens can be detected by solid-phase radioimmunoassay. Further improvements in assay sensitivity will be required to detect antigens, if present, in animals with lower levels of P. aeruginosa bacteremia.
我们评估了一种经改良以能在血清中检测抗原的固相放射免疫测定法，用于检测患有铜绿假单胞菌血症的粒细胞减少兔体内循环抗原的能力。用铜绿假单胞菌脂多糖进行的体外实验表明，用热、氯仿或肝素处理血清 - 脂多糖混合物可使脂多糖检测灵敏度提高8至16倍。氯仿处理能在菌血症兔的血清或血浆中检测到抗原，而在未处理的标本中这些抗原很难检测到或根本检测不到。然而，经氯仿处理的标本偶尔会导致塑料管溶解，从而导致125I标记的抗铜绿假单胞菌免疫球蛋白G出现非特异性结合。将血清在56℃加热30分钟可改善脂多糖 - 血清混合物以及菌血症兔体内的抗原检测。在20只培养阳性的粒细胞减少兔中，20%经加热的血清或血浆中检测到了抗原；15只培养阴性的粒细胞减少兔中均未检测到；38只正常兔中也未检测到。在每毫升血液中有2至300个铜绿假单胞菌菌落形成单位的15只兔中均未检测到抗原，而在每毫升血液中有>10(3)个菌落形成单位的5只兔中，有4只检测到了抗原。我们得出结论，患有高水平铜绿假单胞菌血症的兔血液中存在循环抗原，并且这些抗原可用固相放射免疫测定法检测到。若要检测患有较低水平铜绿假单胞菌血症动物体内（如果存在的话）的抗原，则需要进一步提高检测灵敏度。
