Douglas J T, Steven L M, Hirsch D S, Fujiwara T, Nelson K E, Madarang M G, Cellona R V
University of Hawaii, Department of Microbiology, Honolulu 96822.
Lepr Rev. 1992 Sep;63(3):199-210.
In order to determine the frequency of occurrence of antibodies to semisynthetic antigens of Mycobacterium leprae in clinically healthy nonpatient populations and to establish a 'baseline' for comparison with antibody frequencies in both patients with a history of leprosy and their contacts, ELISAs were conducted using representative sera from two areas: a leprosy endemic area, Cebu City, Philippines and a nonendemic area for leprosy Chicago, Illinois, USA. These sera were tested, by an indirect IgM ELISA, for the presence of antibodies reacting with four semisynthetic antigens based on the phenolic glycolipid I antigen of M. leprae: ND-O-BSA (natural disaccharide with octyl linkage to bovine serum albumin), NT-O-BSA (natural trisaccharide with octyl linkage to BSA), ND-P-BSA (natural disaccharide with phenolic ring linkage to BSA) and NT-P-BSA (natural trisaccharide with phenolic ring linkage to BSA). Using an OD reading > or = 0.16 as positive, the antigen with the lowest background seroreactivity was ND-O-BSA, which reacted with 5/398 (1.3%) sera from Cebu, and 3/426 (0.7%) sera from Chicago. A total of 10 (2.5%) of 398 sera from the endemic area reacted with at least one antigen and 5 (1.3%) sera reacted with all four semisynthetic antigens. Of the 426 sera from Chicago, 12 (2.8%) were reactive with at least one antigen and 3 (0.7%) were reactive with all four semisynthetic antigens. Mean ELISA values for the 22 positive sera for each antigen ranged from 0.17 to 0.3 OD units, while the mean values for all sera in each area ranged from 0.01 to 0.04 OD units for all four antigens. Reactivity of 14 of the positive sera to some antigens, but not all four semisynthetic antigens, indicated that the carrier and linker arms might be associated with this background reactivity. Investigation of alternative linker arms and carriers is warranted. We conclude that nonspecific background reactivity to the semisynthetic antigens representing the PG-I molecule of M. leprae is 0.7-1.3%, based on a > or = 0.16 OD cutoff value. From these data it was concluded that reactivity in individuals free of leprosy was low enough to warrant use of these antigens in a diagnostic setting, such as screening household contacts and highly endemic populations. When incidence and prevalence of leprosy are low, testing with these antigens would not be cost effective, unless applied to high risk individuals.(ABSTRACT TRUNCATED AT 400 WORDS)
为了确定临床健康的非患者群体中麻风分枝杆菌半合成抗原抗体的出现频率，并建立一个“基线”，以便与有麻风病史的患者及其接触者的抗体频率进行比较，我们使用来自两个地区的代表性血清进行了酶联免疫吸附测定（ELISA）：一个麻风病流行地区，菲律宾宿务市；另一个非麻风病流行地区，美国伊利诺伊州芝加哥市。通过间接IgM ELISA检测这些血清中与基于麻风分枝杆菌酚糖脂I抗原的四种半合成抗原发生反应的抗体。这四种半合成抗原分别是：ND - O - BSA（与牛血清白蛋白有辛酯连接的天然二糖）、NT - O - BSA（与牛血清白蛋白有辛酯连接的天然三糖）、ND - P - BSA（与牛血清白蛋白有酚环连接的天然二糖）和NT - P - BSA（与牛血清白蛋白有酚环连接的天然三糖）。以光密度（OD）读数≥0.16为阳性，背景血清反应性最低的抗原是ND - O - BSA，它与来自宿务的5/398（1.3%）血清以及来自芝加哥的3/426（0.7%）血清发生反应。来自流行地区的398份血清中，共有10份（2.5%）与至少一种抗原发生反应，5份（1.3%）血清与所有四种半合成抗原发生反应。在来自芝加哥的426份血清中，12份（2.8%）与至少一种抗原发生反应，3份（0.7%）与所有四种半合成抗原发生反应。每种抗原的22份阳性血清的平均ELISA值在0.17至0.3 OD单位之间，而每个地区所有血清针对所有四种抗原的平均值在0.01至0.04 OD单位之间。14份阳性血清对某些抗原而非所有四种半合成抗原的反应性表明，载体臂和连接臂可能与这种背景反应性有关。有必要研究替代的连接臂和载体。我们得出结论，基于OD截止值≥0.16，对代表麻风分枝杆菌PG - I分子的半合成抗原的非特异性背景反应性为0.7 - 1.3%。从这些数据可以得出结论，麻风病患者个体中的反应性足够低，足以保证在诊断环境中使用这些抗原，例如筛查家庭接触者和高流行人群。当麻风病的发病率和患病率较低时，使用这些抗原进行检测可能不具有成本效益，除非应用于高危个体。（摘要截短至400字）
