Laursen A L, Andersen P L
Department of Infectious Diseases, Marselisborg Hospital, University of Aarhus, Denmark.
Scand J Infect Dis. 1998;30(5):495-9. doi: 10.1080/00365549850161511.
IgG antibodies against Pneumocystis carinii (P. carinii) were detected by an ELISA method using urea-extracted material from human and rat P. carinii as the antigen. Carbohydrate formed a major part of the antigen responsible for reactivity in the ELISA assay, since periodate treatment reduced the reactivity of most sera tested. Cross-reactivity between human and rat P. carinii was detected. However, human serum recognized antigens specific for human P. carinii. With the ELISA method IgG antibody levels were compared between blood donors (n = 40), asymptomatic HIV-antibody positive patients (n = 30) and AIDS patients with (n=22) and without previous P. carinii pneumonia (PCP) (n=21). HIV-infected patients had significantly lower antibody reactivity against the microorganism compared with blood donors. Among HIV-antibody positive patients the highest antibody reactivity was seen in PCP patients. The antibody response to PCP was impaired, since an equal number of patients had an increase and a decrease in antibody reactivity. In conclusion, carbohydrate formed an important part of the P. carinii immunogenic antigen. Cross-reactivity between rat and human P. carinii was demonstrated, but reactivity was somewhat lower using antigen from rats. The antibody level was lower in HIV-infected patients and the ability to mount an antibody response to the infection was impaired, suggesting that the poor antibody response may contribute to the liability of HIV-infected patients to have PCP.
采用酶联免疫吸附测定（ELISA）法，以从人和大鼠卡氏肺孢子虫中提取的尿素提取物为抗原，检测抗卡氏肺孢子虫的IgG抗体。碳水化合物是ELISA检测中产生反应性的主要抗原成分，因为高碘酸盐处理会降低大多数检测血清的反应性。检测到人和大鼠卡氏肺孢子虫之间存在交叉反应性。然而，人血清可识别出人类卡氏肺孢子虫特有的抗原。采用ELISA法，比较了40名献血者、30名无症状HIV抗体阳性患者、22名曾患卡氏肺孢子虫肺炎（PCP）的艾滋病患者以及21名未患过PCP的艾滋病患者的IgG抗体水平。与献血者相比，HIV感染患者对该微生物的抗体反应性显著降低。在HIV抗体阳性患者中，PCP患者的抗体反应性最高。由于抗体反应性增加和降低的患者数量相同，因此对PCP的抗体反应受损。总之，碳水化合物是卡氏肺孢子虫免疫原性抗原的重要组成部分。已证实大鼠和人类卡氏肺孢子虫之间存在交叉反应性，但使用大鼠抗原时反应性略低。HIV感染患者的抗体水平较低，且对感染产生抗体反应的能力受损，这表明抗体反应不佳可能导致HIV感染患者易患PCP。
