Synthesis and immunologic properties in mice of vaccines composed of Staphylococcus aureus type 5 and type 8 capsular polysaccharides conjugated to Pseudomonas aeruginosa exotoxin A.

Epidemiological, serological and in vitro phagocytosis experiments provide evidence that the newly discovered type 5 and type 8 capsular polysaccharides (CPs) are both virulence factors and protective antigens for bacteremia caused by Staphylococcus aureus. Neither type 5 nor type 8 CP elicited serum antibodies when injected into mice. These two CPs were bound to Pseudomonas aeruginosa exotoxin A (ETA) to form conjugates by using the synthetic scheme devised for the CP (Vi) of Salmonella typhi and of pneumococcus type 12F (A. Fattom, W. F. Vann, S. C. Szu, A. Sutton, X. Li, D. Bryla, G. Schiffman, J. B. Robbins, and R. Schneerson, Infect. Immun. 56:2292-2298, 1988; S. C. Szu, A. L. Stone, J. D. Robbins, R. Schneerson, and J. B. Robbins, J. Exp. Med. 166:1510-1524, 1987). Both S. aureus CP-ETA conjugates elicited a rise in CP antibodies. As components of conjugates, both S. aureus CPs acquired T-cell-dependent properties, as shown by their ability to respond to carrier priming and to stimulate booster responses. The conjugate-induced antibodies facilitated type-specific opsonization of S. aureus by human polymorphonuclear leukocytes. The conjugates also induced ETA antibodies which neutralized the native toxin in vitro. Clinical studies of these two conjugates for active or passive immunization of patients at risk for S. aureus bacteremia are planned.

Immunochemical analysis of a Smith-like antigen isolated from two human strains of Staphylococcus aureus.

A surface antigen consisting of aminoglucuronic acid and N-acetyl-L-alanine was isolated from the culture filtrates of two human strains of Staphylococcus aureus. Double diffusion analysis in agar suggested that the antigen is immunologically similar to the alanyl-aminoglucuronic acid capsule of the Smith strain of S. aureus. Quantitative precipitin inhibition studies indicated that N-acetyl-L-alanine is the immunodominant determinant of the acidic antigen. In addition, conjugates consisting of N-acetyl-L-alanine coupled to bovine serum albumin gave a significant precipitin reaction with anti-staphylococcal serum which is rich in alanyl-aminoglucuronic acid polymer antibodies. Antibodies with N-acetyl-L-alanine specificity were isolated from N-acetyl-L-alanine-Sepharose immunoabsorbent columns. Double diffusion analysis in agar indicated that the eluted antibodies were serologically reactive and belonged to the IgG class of immunoglobulins.

Immunochemistry of an acidic antigen isolated from a Staphylococcus aureus.

Staphylococcus aureus, strain 7007, was shown to possess an anti-phagocytic surface antigen. This surface antigen was separated from the species-specific teichoic acid by a combination of DEAE-cellulose chromatography and Bio-Gel filtration. Chemical analyses indicated that the 7007 surface antigen consisted of aminomannuronic acid and fucosamine. Immunochemical analyses suggested that this polymer, although consisting of the same components as the staphylococcal T-antigen described by Wu and Park was, in fact, immunologically distinct from the T-antigen. Antibodies directed against the surface antigen were isolated from anti-7007 rabbit serum by affinity chromatography. These antibodies were shown to belong to the IgG class of immunoglobulins and were effective in enhancing in vitro phagocytosis of 7007 cells by polymorphonuclear leukocytes.

Filamentous capsulated streptococci from the human respiratory tract. II. Antigenic structure of provisional capsular types 89 and 83-89.

Two immunologically distinct polysaccharides have been isolated from the filamentous alpha-hemolytic streptococcus of provisional capsular type 89, recovered from the human respiratory tract. Chemical analyses indicate that the capsular polysaccharide consists of glucose, galactose, and a small amount of rhamnose, whereas the cell wall-associated polymer contains galactosamine, glucosamine, glucose, and phosphorus. Immunological studies suggest that the capsular polysaccharide is type specific and that the cell wall-associated carbohydrate, which cross-reacts with the C(8), or cell wall-like capsular polysaccharide of pneumococcus, may be group specific. A noncapsulated variant of the prototypic streptococcus of provisional type 89 was shown to possess the same cell wall-associated carbohydrate as the strain from which it was derived, but it proved to be poorly antigenic in rabbits. A filamentous capsulated streptococcus reacting with antisera to filamentous streptococci of both provisional capsular types 83 and 89 has been found to produce two capsular polysaccharides, each of which reacts with antibody to one of the aforementioned unitypic strains and represents an unusual binary capsulated streptococcus.

Filamentous capsulated streptococci from the human respiratory tract. I. Antigenic attributes of provisional capsular type 83 and its relationship to streptococci of so-called group M.

Two immunologically reactive polysaccharides have been isolated from the cell walls and from culture filtrates of a filamentous alpha-hemolytic streptococcus provisionally designated capsular type 83. Both polysaccharides were purified by diethylaminoethyl-cellulose chromatography. Analysis indicates that the capsular polysaccharide consists of galactose and phosphorus, whereas the cell wall polysaccharide contains galactosamine, glucosamine, glucose, and phosphorus. On the basis of immunochemical experiments, it is suggested that the capsular polysaccharide is composed of galactose-phosphate units with terminal galactose residues at the nonreducing end. It has also been found that the capsular antigen of streptococcus type 83 is shared by a number of streptococcal strains classified in Lancefield's group M. The cell wall polysaccharide of streptococcus type 83 cross-reacts with antibody to the C(s), or cell wall-like capsular, polysaccharide of Diplococcus pneumoniae, and this cross-reactivity may be a reflection that the streptococcal antigen possesses certain structural features which are similar to those of pneumococcal C and C(s) polysaccharides.

Filamentous capsulated streptococci from the human respiratory tract. 3. Immunochemical studies of the cross-reactivity between the cell wall antigens of a filamentous streptococcus and of pneumococcus.

A cell wall-associated polysaccharide has been isolated from a noncapsulated mutant, 89R50, of the alpha-hemolytic filamentous streptococcus of provisional capsular type 89. Chemical analysis of the polysaccharide indicates that it consists of galactosamine, glucosamine, glucose, and phosphorus. Immunological cross-reactivity was observed between the streptococcal cell wall antigen and antibody to the cell wall-like capsular polysaccharide of pneumococcus. This cross-reactivity appears attributable to similarities in the teichoic acid moieties rather than in the mucopeptide moieties of the two polymers. No chemical or immunological differences were observed in the cell wall carbohydrate of the noncapsulated streptococcus, 89R50, and that of its capsulated progenitor. It is suggested that antibody to this cell wall polysaccharide might serve as a basis for grouping other filamentous strains of streptococci of diverse capsular types, the cell wall antigens of which show similar cross-reactivity with that of pneumococcus.