Baughn R E, Demecs M, Taber L H, Musher D M
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.
Infect Immun. 1996 Jul;64(7):2457-66. doi: 10.1128/iai.64.7.2457-2466.1996.
The antigenicity of the 15-kDa lipoprotein of Treponema pallidum (Tpp15 or TpN15) was comprehensively evaluated in epitope-scanning studies with overlapping deca- and octapeptides and polygonal rabbit and human infant immunoglobulins (Igs) and antisera. This approach enabled us to identify potentially important regions and to determine the optimal dilutions of Igs or antisera for use in further studies. IgM and IgG from both species were capable of recognizing multiple, continuous epitopes. A total of 13 peptides, principally clustered in the central regions of the protein, were recognized by all syphilitic sera and Ig fractions. On the basis of window analyses, frequency profiles, and alanine substitution studies, five heptapeptides were selected for mimetic studies. Two of these five immunodominant, continuous epitopes initially appeared to be species specific; however, antisera elicited against mimetics of all five epitopes were polyspecific, recognizing similar motifs on several other treponemal proteins, including those of avirulent organisms. The only mimetic which yielded positive reactions with infant IgM and syphilitic sera in the absence of cross-reactions with rabbit antisera to avirulent treponemes was the variant of the VMYASSG motif. These findings are relevant to the development of simple, inexpensive assays for the serodiagnosis of active syphilis.
采用重叠十肽和八肽以及多克隆兔和人类婴儿免疫球蛋白（Ig）及抗血清进行表位扫描研究，全面评估了梅毒螺旋体15 kDa脂蛋白（Tpp15或TpN15）的抗原性。这种方法使我们能够识别潜在的重要区域，并确定用于进一步研究的Ig或抗血清的最佳稀释度。两种物种的IgM和IgG都能够识别多个连续表位。所有梅毒血清和Ig组分都识别出总共13种肽，主要集中在该蛋白的中央区域。基于窗口分析、频率分布和丙氨酸替代研究，选择了5种七肽进行模拟研究。这5个免疫显性连续表位中的2个最初似乎具有物种特异性；然而，针对所有5个表位模拟物产生的抗血清具有多特异性，可识别其他几种梅毒螺旋体蛋白上的相似基序，包括无毒力生物体的蛋白。在不与针对无毒力梅毒螺旋体的兔抗血清发生交叉反应的情况下，唯一与婴儿IgM和梅毒血清产生阳性反应的模拟物是VMYASSG基序的变体。这些发现与开发用于活动性梅毒血清诊断的简单、廉价检测方法相关。
