Serology structure

A seminal review by Stacey in 1947 on Aspects of Immunochemistry, and a survey a year later on Chemistry of Immunopolysaccharides, pointed the way to much of his future research. Taken in toto, his chemical work laid a firm basis for correlating the chemical and serological approaches to structure determinations of antigenic polysaccharides. 

By 1945, Stacey speculated about the possibility of a structural relationship between Pneumococcus capsular polysaccharides and those produced by other organisms. With Miss Schliichterer, he had examined the capsular polysaccharide of Rhizobium radicicolum. This polysaccharide gave a precipitin reaction in high dilution, not only with Type III Pneumococcus antiserum, but also mixed with antisera from other Pneumococcus types. The chemical evidence indicated that the polysaccharide resembled the specific polysaccharides of Types I and II Pneumococcus. A decade later, the acidic capsular polysaccharide from Azoto-bacter chroococcum, a soil organism, was studied. It, too, produced serological cross-reactions with certain pneumococcal specific antisera. Although the molecular structure of the polysaccharide was not established, adequate evidence was accumulated to show a structural relationship to Type III Pneumococcus-specific polysaccharide. This was sufficiently close to account for the Type III serological cross-relationship. 

Another indicator that the SEs share similar structures is evidenced by cross-reactivity and neutralization with antibodies. Several years ago, when there were less SEs known, these molecules were considered serologically distinct entities as determined by antisera and relatively insensitive immunodiffusion assays. However, subsequent studies employing a more sensitive technique (ELISA) with polyclonal and monoclonal antibodies clearly reveal that common epitopes do indeed exist between these toxins. 

First, oligosaccharide 1 (see Table X) represents that structure shown by serological tests285 to be largely responsible for Le antigenic activity. Both this structure and the disaccharide N-acetyl-... 

Serological and enzymic techniques involving various glycosidases have been used for determining certain structural features of the secreted blood-group substances. Reviews of these data are available,241,285 and so these aspects will not be discussed. 

In Figure 1, the structures of the Ra to Re lipopolysaccharides have been indicated. These incomplete lipopolysaccharides which are devoid of O chains and parts of the core are formed by R mutant strains which are defective in the synthesis of the O chain (Ra) or of the core (Rb-Re) (reviewed by Luderitz et al., 1982). Ra to Re lipopolysaccharides represent intermediates in lipopolysaccharide biosynthesis. They express distinct serological specificities since the respective terminal sugar units act as the main immunodeterminant. The different R lipopolysaccharides and the respective R mutants, therefore, can be differentiated by serological methods. 

Block Synthesis. In contrast to this published work we have recently investigated the use of block synthesis to obtain a related frame shifted tetrasaccharide sequence, Rha(al 3)Rha (al 3)GlcNAc(f l-2)Rha(a)-0-R, previously unavailable to us. This structure was considered essential since serological screening had shown the trisaccharide Rha(al-3)Glct4Ac(f l-2)Rha(a)-0-R to possess higher activity than either of the previously synthesized tetrasaccharldes, Rha(al 2)Rha(al-3)Rha(al-3)GlcNAc(( )-0-R or... 

Vann, W.F. and Jann, K. (1979) Structure and serological specificity of the K13 poly-antigenic polysaccharide (K13 antigen) of urinary tract infective E.coli. Infect. Immun. 25 85-92... 

Gigg J, Gigg R, Payne S, Conant R (1986) Synthetic studies on the major serologically active glycolipid from Mycobacterium leprae, in Klein RA, Schmitz B (eds) Topics in lipid research — from structural elucidation to biological function, Royal Society of Chemistry p. 119... 

E. Romanowska, A. Romanowska, C. Lugowski, and E. Katzenellenbogen, Structural and serological analysis of CitroZiacter-036-specific polysaccharide, the homopolymer of (pi-2)-linked 4-deoxy-D-araWno-hexopyranosyl units, Eur. J. Biochem., 121 (1981) 119-123. 

The 8-O-acetyl-associated epitope of legionaminic acid was also found in P. fluorescens ATCC 49271, which has the same OPS structure 17 as L. pneumophila serogroup l32,56 (Fig. 5). This epitope, possibly along with other, yet uncharacterized cross-reactive epitopes, is likely responsible for the serological cross-reactivity exhibited by P. fluorescens and distantly related L. pneumophila. 

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