A method is described for estimating quantitatively the frequency of transformation of pneumococci to new capsular types. It is found that, when S-(III) cells are exposed to deoxyribonucleic acid (DNA) from wild-type I strains, transformation to SI occurs at a frequency 20 to 60 times that of transformation to the binary type SI-III. SI markers on DNA isolated from binary strains behave qualita...

Bacteroides is an abundant genus of bacteria of the human intestinal microbiota. Bacteroides species synthesize a large number of capsular polysaccharides (PS), a biological property not shared with closely related oral species, suggesting importance for intestinal survival. Bacteroides fragilis, for example, synthesizes eight capsular polysaccharides per strain, each of which phase varies via ...

The relative lack of memory for IgG antipolysaccharide responses is believed to be secondary to the inability of polysaccharides to associate with MHC class II molecules and thus a failure to recruit cognate CD4+ T cell help. However, little is known concerning the role of T cells and the generation of memory for antipolysaccharide Ig responses to intact extracellular bacteria. We used heat-kil...

There is controversy on the role of IgM memory and switched memory B lymphocytes in the Ab response to T cell-independent and T cell-dependent Ags. We transplanted SCID/SCID mice with human B lymphocyte subsets and immunized them with heat-inactivated Streptococcus pneumoniae or with a pneumococcal vaccine. Inactivated S. pneumoniae and soluble pneumococcal capsular polysaccharides elicited an ...

Methods are described for the separation of the C or cell wall polysaccharide from the C(s) or soluble C-like capsular polysaccharide of C(s) pneumococcal strains. Immunologic analysis has shown that both the C and C(s) polysaccharides of a variety of pneumococcal strains are heterogeneous and that the dissimilarities appear to reside in the mucopeptide portion of the molecule or in the region ...

Group B streptococcal infection is a major cause of neonatal mortality. Antibody to the capsular polysaccharide protects against invasive neonatal disease, but immunization with capsular polysaccharides fails to elicit protective antibody in many recipients. Conjugation of the polysaccharide to tetanus toxoid has been shown to increase immune response to the polysaccharide. In animal models, C ...

1. An organism has been isolated from peat soil which decomposes the specific capsular polysaccharide of Type III Pneumococcus. 2. The isolation has been made possible by the use of a synthetic mineral medium containing the specific polysaccharide as sole source of carbon. By repeated transfers in this medium the potential capacity of the organism to decompose the specific substance has been pr...

Numerous studies have suggested that cryptococcal capsular polysaccharide could induce an immunological paralysis. To investigate this possibility, mice were given various concentrations of purified cryptococcal polysaccharide and then 14 days later were challenge-immunized with the same material in Freund's incomplete adjuvant. Anticryptococcal agglutinin titers were determined at various peri...

We resolved previous conflicting results concerning the presence of 3-hydroxybutyryl substituents on the extracellular acidic polysaccharide from Rhizobium trifolii 0403. These substituents were indeed present in the polysaccharide and in the oligosaccharide fragments obtained by hydrogen fluoride solvolysis of the extracellular and capsular polysaccharides of the bacteria grown on plates. The ...

The polysaccharide capsule of Bacteroides fragilis has been shown to be important in the virulence of the organism. The capsular polysaccharide (CP) of B. fragilis has been extensively purified. Using a murine model of intraabdominal abscess formation, we have been able to demonstrate cellular immunity to the capsular polysaccharide of B. fragilis. Immunization of C57BL/10J mice with the CP ove...