López-Marín L M, Gautier N, Lanéelle M A, Silve G, Daffé M
Département des Glycoconjugués et Biomembranes du LPTF du CNRS, Toulouse, France.
Microbiology (Reading). 1994 May;140 ( Pt 5):1109-18. doi: 10.1099/13500872-140-5-1109.
Mycobacterium abscessus and Mycobacterium chelonae, two members of the Mycobacterium fortuitum complex, contain five major glycolipids. A combination of NMR spectroscopy, fast atom bombardment mass spectrometry and chemical degradation was used to elucidate their structures. All the compounds belong to the family of glycopeptidolipids. A 6-deoxy-alpha-L-talosyl unit, which may bear one or two acetyl groups, invariably occupies the site of glycosylation on the threonine residue in the various compounds. A 3,4-di-O-methyl- or 2,3,4-tri-O-methyl-alpha-L-rhamnosyl unit modifies the alaninol end of the diglycosylated molecules. Both species also contain a multiglycosylated compound consisting of alpha-L-rhamnosyl-(1-->2)-3,4-di-O-methyl-alpha-L-rhamnosyl linked to alaninol, which belongs to the class of new variants of glycopeptidolipids recently described. Using an ELISA, the latter glycolipid as well as the diglycosylated ones (not previously reported to be antigenic), were shown to react with the serum raised against the whole lipid antigens of M. chelonae. A comparative serologic study of the native and chemically modified glycopeptidolipid antigens allowed the identification of their epitope as the 3,4-di-O-methyl-alpha-L-rhamnosyl residue. Similar experiments conducted on the glycopeptidolipids isolated from the serologically cross-reacting species M. peregrinum led to the conclusion that the epitope identified in M. chelonae and M. abscessus was involved in the cross-reactions and demonstrated the existence of a second haptenic moiety in the glycolipids of M. peregrinum, the 3-O-methyl-alpha-L-rhamnosyl unit. In addition to this latter non-shared epitope, the recently described sulfated glycopeptidolipid antigen of M. peregrinum did not react with the M. chelonae serum, thus further explaining the difference in the seroreactivity within the complex.
脓肿分枝杆菌和龟分枝杆菌是偶然分枝杆菌复合体的两个成员，它们含有五种主要糖脂。采用核磁共振光谱、快原子轰击质谱和化学降解相结合的方法来阐明其结构。所有化合物均属于糖肽脂家族。一个6 - 脱氧 -α-L-塔罗糖基单元，可能带有一个或两个乙酰基，总是占据各种化合物中苏氨酸残基上的糖基化位点。一个3,4 - 二 -O-甲基 - 或2,3,4 - 三 -O-甲基 -α-L-鼠李糖基单元修饰双糖基化分子的丙氨醇末端。这两个菌种还含有一种多糖基化化合物，由α-L-鼠李糖基-(1→2)-3,4 - 二 -O-甲基 -α-L-鼠李糖基连接到丙氨醇组成，属于最近描述的糖肽脂新变体类别。使用酶联免疫吸附测定法（ELISA），发现后一种糖脂以及双糖基化糖脂（以前未报道具有抗原性）与针对龟分枝杆菌全脂抗原产生的血清发生反应。对天然和化学修饰的糖肽脂抗原进行的比较血清学研究确定其表位为3,4 - 二 -O-甲基 -α-L-鼠李糖基残基。对从血清学交叉反应菌种—— Peregrinum分枝杆菌中分离出的糖肽脂进行的类似实验得出结论，在龟分枝杆菌和脓肿分枝杆菌中鉴定出的表位参与了交叉反应，并证明在Peregrinum分枝杆菌的糖脂中存在第二个半抗原部分，即3 -O-甲基 -α-L-鼠李糖基单元。除了后一种非共享表位外，最近描述的Peregrinum分枝杆菌硫酸化糖肽脂抗原不与龟分枝杆菌血清反应，从而进一步解释了该复合体内血清反应性的差异。
