Sjögren A M, Holmberg H, Krook A
Diagn Microbiol Infect Dis. 1987 Mar;6(3):239-48. doi: 10.1016/0732-8893(87)90018-6.
Crossreactions between bacteria occurring more or less frequently in the respiratory tract were investigated using an enzyme-linked immunosorbent assay (ELISA) developed for the detection of pneumococcal C-polysaccharide. A collection of 218 strains was investigated: 30 Streptococcus pneumoniae, 120 alpha-streptococci, and 68 strains representing other species. Strong crossreactions were observed with 36% of the alpha-streptococci and with two of 11 Staphylococcus aureus strains. The collection of alpha-streptococci consisted of 90 fresh clinical isolates and 30 stock strains. Almost all crossreactions of alpha-streptococci were found among the clinical isolates. Among the stock strains only one of four Streptococcus mitis strains was positive. Pneumococcal C-polysaccharide and phosphorylcholine inhibited the reactions in ELISA with monoclonal antibodies against pneumococcal C-polysaccharide, as well as with a polyclonal antiserum against pneumococcal C-polysaccharide. We suggest that the cross reactions between alpha-streptococci and pneumococci depend on the presence of phosphorylcholine as a common antigenic determinant. The crossreaction in the ELISA with some Staphylococcus aureus strains may be explained by the presence of protein A binding to the Fc portion of the antibodies. When the 10 alpha-streptococci that showed the strongest crossreactions and ten pneumococci representing different types were tested in different concentrations the absorbance values were lower for most alpha-streptococci compared with the pneumococci. This explains that false positive results with alpha-streptococci do not seem to constitute a practical problem in this ELISA developed for detection of pneumococcal C-polysaccharide in samples from patients with pneumonia.
利用一种为检测肺炎球菌C多糖而开发的酶联免疫吸附测定法（ELISA），对呼吸道中或多或少频繁出现的细菌之间的交叉反应进行了研究。对218株菌株进行了研究：30株肺炎链球菌、120株α-链球菌以及代表其他菌种的68株菌株。在36%的α-链球菌以及11株金黄色葡萄球菌中的2株中观察到了强烈的交叉反应。α-链球菌的菌株集合包括90株新鲜临床分离株和30株标准菌株。几乎所有α-链球菌的交叉反应都出现在临床分离株中。在标准菌株中，仅4株缓症链球菌中的1株呈阳性。肺炎球菌C多糖和磷酸胆碱抑制了ELISA中针对肺炎球菌C多糖的单克隆抗体以及针对肺炎球菌C多糖的多克隆抗血清的反应。我们认为，α-链球菌和肺炎球菌之间的交叉反应取决于作为共同抗原决定簇的磷酸胆碱的存在。ELISA中与一些金黄色葡萄球菌菌株的交叉反应可能是由于蛋白A与抗体的Fc部分结合所致。当对显示出最强交叉反应的10株α-链球菌和代表不同类型的10株肺炎球菌进行不同浓度测试时，与肺炎球菌相比，大多数α-链球菌的吸光度值较低。这说明在为检测肺炎患者样本中的肺炎球菌C多糖而开发的这种ELISA中，α-链球菌产生的假阳性结果似乎并不构成实际问题。
