Isolation and characterization of the serotype g carbohydrate moiety from an enzyme lysate of Streptococcus mutans 6715 cell walls

Haptenated streptococcal antigens elicit either T cell-dependent type 1 or T cell-independent type 2 immune responses

Antigens of Streptococcus mutans 6715 (alternatively designated serotype g Streptococcus sobrinus), including whole cells (WC g), cell walls (CW g), peptidoglycan (PG g) and serotype carbohydrate (Ml g) were coupled with trinitrophenyl (TNP), and the nature of the immune response to each immunogen was determined in normal and X-linked immunodeficient (xid) murine spleen cell cultures. Responses to TNP-WC g, -CW g and -PG g and to the classical type 1 antigen TNP-Brucella abortus occurred in both xid and normal splenic cultures, while TNP-Ml g only triggered immune responses in normal spleen cell cultures, suggesting that the former three antigens are type 1 and the latter type 2. Further support for the type 2 nature of TNP-Ml g was the finding that Peyer's patch cell cultures from both xid (which contain mature B cells) and normal mice supported responses to TNP-Ml g and TNP-Ficoll, while xid splenic cultures failed to support responses to either type 2 antigen. The three type 1 TNP-S. mutans antigens induced responses in nude spleen cell and in purified splenic B cell cultures, but required T cells for in vitro responses to lower doses of immunogen. On the other hand, TNP-Ml g induced anti-TNP PFC responses at several antigen concentrations in purified B cell cultures, without requirement for added T cells. These studies show that the intact S. mutans cell, as well as CW g and PG g, acts as a T cell-dependent (TD) type 1 antigen, while the serotype carbohydrate (Ml g) induces a T cell-independent (TI) type 2 response. Thus, the intact bacterium is a TD type 1 antigen, whereas its purified components are either type 1 or type 2 antigens and differ significantly in terms of their T cell dependence.

Biological monitoring of nickel

Measurements of nickel in body fluids, excreta, and tissues from humans with occupational, environmental, and iatrogenic exposures to nickel compounds are comprehensively reviewed. Correlations between levels of human exposures to various classes of nickel compounds via inhalation, oral, or parenteral routes and the corresponding concentrations of nickel in biological samples are critically evaluated. The major conclusions include the following points: Measurements of nickel concentrations in body fluids, especially urine and serum, provide meaningful insights into the extent of nickel exposures, provided these data are interpreted with knowledge of the exposure routes, sources, and durations, the chemical identities and physical-chemical properties of the nickel compounds, and relevant clinical and physiological information, such as renal function. Nickel concentrations in body fluids should not, at present, be viewed as indicators of specific health risks, except in persons exposed to nickel carbonyl, for whom urine nickel concentrations provide prognostic guidance on the severity of the poisoning. In persons exposed to soluble nickel compounds (e.g., NiCl2, NiSO4), nickel concentrations in body fluids are generally proportional to exposure levels; absence of increased values usually indicates non-significant exposure; presence of increased values should be a signal to reduce the exposure. In persons exposed to less soluble nickel compounds (e.g., Ni3S2,NiO), increased concentrations of nickel in body fluids are indicative of significant nickel absorption and should be a signal to reduce the exposures to the lowest levels attainable with available technology; absence of increased values does not necessarily indicate freedom from the health risks (e.g., cancers of lung and nasal cavities) associated with exposures to certain relatively insoluble nickel compounds.

Purification and immunochemical properties of a protein antigen from serotype g Streptococcus mutans

A proteinaceous antigen (PAg) was purified from the culture supernatant of Streptococcus mutans 6715 (serotype g) by ultrafiltration, ammonium sulfate precipitation, DEAE-Sephacel ion-exchange chromatography, Phenyl-Sepharose CL-4B hydrophobic chromatography, and subsequent Sephacryl S-300 gel filtration. A yield of 0.1 mg of PAg was obtained from a liter of culture supernatant. The isoelectric point and molecular weight of PAg were pH 4.6 and 210,000, respectively. It contained 35% sugar, which was identified as glucose by gas-liquid chromatography. Amino acid analysis revealed that PAg contains 28% acidic and 11% basic amino acid residues. PAg retained its antigenicity after heating at 80 C for 10 min in deionized water, or after treatment with 0.1 M HC1 or 0.1 M NaOH at 37 C for 1 hr. Immunodiffusion and immunoelectrophoresis analyses revealed that PAg is serologically distinct from other cell-surface antigens such as serotype-specific polysaccharide and lipoteichoic acid. A cross-reaction between PAg and a protein antigen similarly prepared from serotype c S. mutans was observed in immunodiffusion tests.

Antigen analyses of serotypes of streptococcus mutans using a monoclonal antibody elaborated against serotype g polysaccharide antigen

A hybridoma (F4B) which produced a monoclonal antibody (mAb) specific for serotype g carbohydrate antigen (RRg) of Streptococcus mutans 6715 was obtained. The F4B mAb cross-reacted with purified carbohydrate antigens of serotype d (RRd) and serotype h (TCAh). In immunodiffusion tests, F4B mAb produced a stable precipitin band with RRg, while the band developed between the mAb and RRd/TCAh in the cold disappeared when incubated at room temperature. The immunoprecipitin reaction between F4B mAb and RRg was strongly inhibited upon addition of lactose.

Immunochemical characteristics of Streptococcus mutans serotype h carbohydrate antigen

Serotype h carbohydrate antigen was prepared from cell walls of Streptococcus mutans strain MFe28 of monkey origin. The h antigen was extracted from the cell walls with 5% trichloracetic acid at 4 C, and purified by DEAE-Sephadex A-25 ion exchange chromatography followed by Sephacryl S-300 gel filtration. The purified antigen was composed of galactose (75%), glucose (16%), and rhamnose (3%). Although the antiserum against whole cells of S. mutans MFe28 gave a strong cross reaction with serotype d S. mutans, serotype h-specific antiserum could be obtained by adequate adsorption. The precipitin reactions and hapten inhibition test using serotype h-specific antiserum showed that galactose, glucose, and their derivative sugars were markedly potent inhibitors. It was concluded that the serotype h antigen is immunologically distinguishable from the known serotypes of S. mutans, although it is closely related to serotype d antigen of S. mutans.