Capsular antigens, containing

Not all capsular polysaccharides of uropathogenic and invasive coli bacteria contain KDO. Some of the non-KDO capsular polysaccharides are shown in Figure 12 (11-16). These are the Kl, K2, K5 and K51 polysaccharides. The Kl polysaccharide is a poly-a-2.8-N-acetyl-neuraminic acid and has been known as colominic acid since many years (11). Its structure which is identical with that of the capsular antigen of Neisseria meningitidis B has first been reported by McGuire and Binkley... 

Pneumococcal polysaccharide vaccine (Pneumovax 23 and Pnu-Immune 23) is a mixture of highly purified capsular polysaccharides from 23 of the most prevalent or invasive types of S. pneumoniae seen in the Umted States. Serotypes included are 1,2, 3, 4, 5, 6B, 7F, 8, 9N, 9V lOA, 12F, 14, 15B, 17F, 18C, 19A, 20, 22F, 23F, and 33F. These 23 types represent 85% to 90% of all blood isolates and 85% of pneumococcal isolates from other generally sterile sites seen in the United States. The vaccine is administered intramuscularly or subcutaneously as a single 0.5-mL dose. Each 0.5-mL dose of vaccine contains 25 meg of each polysaccharide type dissolved in isotonic saline solution (for a total of 575 meg polysaccharide) and 0.25% phenol as preservative. Significant cross-reactivity with other pneumococcal capsular antigens not represented in the vaccine does not... 

Constit. of the capsular antigen of certain types of Klebsiella where the mannose unit contains a 4,6-pyruvic acetal, e.g. K5. Also present in the repeating unit of the acidic polysaccharide from Mycobacterium lacticolum where the mannose unit is substituted at 0(4) by a (5)-l-carbox-yethyl group. 

The first report of the occurrence of KDO in a structure other than LPS was that of Taylor47 on the capsular polysaccharide (K-antigen) of a clinical isolate, Escherichia coli LP1092. Almost simultaneously, Bhattachaijee and coworkers83 described an exopolysaccharide from Neisseria meningitidis serogroup 29e. This material contains KDO... 

Modem subunit vaccines contain one or more selected antigenic subunits that have been found to provide protection against a particular pathogen. They are better defined from a physicochemical aspect and have fewer side effects than vaccines, which contain intact cells, whether inactivated or attenuated. Current subunit antigens include viral and bacterial proteins as well as bacterial capsular polysaccharides. 

B. L. Reuhs, R. W. Carlson, and J. S. Kim, Rhizobium fredii and Rhizobium meliloti produce 3-deoxy-D-marmo-2-octulosonic acid-containing polysaccharides that are structurally analogous to group II K antigens (capsular polysaccharides) found in Escherichia coli, J. Bacteriol., 175 (1993) 3570-3580. 

It is interesting that polysaccharides obtained from O inagglutinable, capsular strains (having K antigens) were reported to contain uronic acid neutral sugars were also present, however, and 0 antigen specificity was also detected in the products. 

Pneumococcal vaccine is composed of a saline solution containing the purified capsular polysaccharides of 23 types of Streptococcus pneumoniae. The improved 23-valent vaccine, which replaced a 14-valent vaccine at the beginning of the 1980s, contains antigens to pneumococcal types that are responsible for about 85% of bacteremic pneumococcal pneumonia. 

A variety of glycans with important stmctural and functional roles are produced as part of bacteria cell walls. Capsular polysaccharides (CPS), teichoic acids, and lipopolysaccharides (LPS) are the three most important and represent the bacterial first line of defense against complement and bacteriophages. The carbohydrate portion of this glycoconjugate contains the major antigenic determinants that distinguish various serotypes of bacteria [1]. 

Salmonella typhi contain antigen O (somatic) and antigen H (flagellar) which give rise to host antibodies. The antigens are lipopolysaccharides which are located in the outer membrane of Salmonella baciUi. Salmonella typhi is further identified by the additional presence of antigen Vi (capsular). A fourfold or over rise of antibody titers to O and H antigens. A 2-weeks apart in paired samples is indicative of typhoid fever. 

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