Mucin model for group B type III streptococcal infection in mice

Fleming, D O

doi:10.1128/iai.27.2.449-454.1980

Cited by 12 publications

(10 citation statements)

References 16 publications

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“…Male C3H/HeN mice, 13-wk-old and ~30 g, were obtained from the National Cancer Institute. The mucin model of Fleming (9,10) was used in all experiments. A 10% (wt/vol) suspension of type II hog gastric mucin (Sigma Chemical Co.) in Dulbecco's balanced salt solution was prepared and autoclaved.…”

Section: Methodsmentioning

confidence: 99%

Protection of mice from experimental infection with type III group B Streptococcus using monoclonal antibodies.

Egan

Pritchard

Dillon

et al. 1983

The Journal of Experimental Medicine

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It is widely believed that antibodies to the group B streptococcal (GBS) typespecific polysaccharides are of major importance in human host defenses against GBS infection. All four of the type-specific polysaccharides elicit antibodies against at least two forms of the antigens: a complete antigen that contains Nacetylneuraminic acid (sialic acid) at the nonreducing ends of the side chains and an incomplete or nonsialated antigen (1-4). This was first demonstrated for the type II polysaccharide by Lancefield and Freimer (1) when they showed that rabbit antisera directed against either the complete or incomplete antigen would protect mice from a lethal challenge of live type II organisms. They were unable to carry out studies with type III GBS using similar passive protection tests because these organisms were not by themselves pathogenic for mice.The question of antibody specificity in protection against type III GBS infections remains controversial. There are conflicting reports regarding the protective properties of human and rabbit antibodies directed against the type III antigens and against the capsular polysaccharide of the type 14 pneumococcus, which cross-reacts with the incomplete GBS type III antigen (5). Although it is possible to select for certain specificities in anti-GBS serum by specific absorptions with purified antigens, as was done by Lancefield and Freimer (1), the polyclonal nature of antisera makes it difficult to clearly determine the immunoprotective effects of various specificities and different isotypes of the antibodies in question.Harris et al. (6) recently reported that mice could be protected against GBS types Ia, Ib, Ic, or II by antibody-producing tumors formed 2 wk after subscapular injection of hybridoma cells. The protection was serotype specific. Similar experiments could not be carried out using type III GBS because this serotype was not virulent in their mouse model. This report describes the production of mouse hybridoma antibodies of different isotypes directed against both sialated and nonsialated forms of the GBS type III polysaccharide. The protective properties of antibodies were examined under conditions where type III GBS were lethal for mice.

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Section: Methodsmentioning

confidence: 99%

Protection of mice from experimental infection with type III group B Streptococcus using monoclonal antibodies.

Egan

Pritchard

Dillon

et al. 1983

The Journal of Experimental Medicine

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“…1D), suggesting that the mucin-enhanced virulence in A. baumannii is not restricted to BALB/c mice. In this regard, other mouse strains, such as ICR-Swiss, Swiss White, and CF-1, previously have been used in similar models (16,18,19,26), although actual magnitudes of the enhancement in some of those studies had not been reported in detail.…”

Section: Resultsmentioning

confidence: 99%

“…Enhancement of in vivo bacterial virulence and infection by porcine mucin is not a phenomenon unique to A. baumannii. Indeed, mucin enhances the infection or virulence of a wide range of Gram-positive and -negative bacteria, although the magnitude of the effect varies from bacterium to bacterium and even from isolate to isolate (15)(16)(17)(18)(19). Apart from intraperitoneal inoculation, admixture of mucin with bacterial inoculum has also been applied to enhance other routes (intranasal [i.n.…”

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confidence: 99%

Potential Mechanisms of Mucin-Enhanced Acinetobacter baumannii Virulence in the Mouse Model of Intraperitoneal Infection

et al. 2019

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Porcine mucin has been commonly used to enhance the infectivity of bacterial pathogens, including Acinetobacter baumannii, in animal models, but the mechanisms for enhancement by mucin remain relatively unknown. In this study, using the mouse model of intraperitoneal (i.p.) mucin-enhanced A. baumannii infection, we characterized the kinetics of bacterial replication and dissemination and the host innate immune responses, as well as their potential contribution to mucin-enhanced bacterial virulence. We found that mucin, either admixed with or separately injected with the challenge bacterial inoculum, was able to enhance the tissue and blood burdens of A. baumannii strains of different virulence. Intraperitoneal injection of A. baumannii-mucin or mucin alone induced a significant but comparable reduction of peritoneal macrophages and lymphocytes, accompanied by a significant neutrophil recruitment and early interleukin-10 (IL-10) responses, suggesting that the resulting inflammatory cellular and cytokine responses were largely induced by the mucin. Depletion of peritoneal macrophages or neutralization of endogenous IL-10 activities showed no effect on the mucin-enhanced infectivity. However, pretreatment of mucin with iron chelator DIBI, but not deferoxamine, partially abolished its virulence enhancement ability, and replacement of mucin with iron significantly enhanced the bacterial burdens in the peritoneal cavity and lung. Taken together, our results favor the hypothesis that iron at least partially contributes to the mucin-enhanced infectivity of A. baumannii in this model.

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“…Bacterial strain variation in mouse lethality tests. Using the laboratory reference strain (SS620) from previous studies (10) and the clinical isolate (M732) of type III S. agalactiae, mucin was found to enhance the level of virulence for mice as measured by a reduction in the number of CFU required to produce an LD50. Although mucin lowered the LD50 significantly in both strains, M732 required more CFU (450) than the SS620 (93) ( Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…Unprotected mice were given an i.p. injection of 107 colony-forming units (CFU) of SS620 GBS serotype III in either Todd-Hewitt broth (Difco) or 5% mucin (10). Subsequently, blood cultures were obtained from each of two mice at intervals of 0.25, 0.5, 0.75, 1, 2, and 20 h by aspiration of the capillary plexus behind the eye.…”

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confidence: 99%

Mouse protection assay for group B streptococcus type III

Fleming¹

1982

Infect Immun

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The mucin model for group B Streptococcus (GBS) type III was used to assay the protective effect of sera against a type III challenge in mice. Hyperimmune rabbit sera, prepared by the Lancefield method against the laboratory reference strain (SS620) and a clinical isolate (M732), protected against a lethal challenge with either strain of GBS type III. Absorption of the sera with either of these type III strains removed the protective effect. Neither normal rabbit sera nor heterologous antisera (anti-Ia, SS615) provided protection; however, protection was obtained with pooled human gamma globulin. Sera from adult volunteers were tested to assay protective levels in the mouse model. Human sera enhanced the mouse lethality of the clinical isolate, M732, but not the laboratory reference strain, SS620. Sera from adults vaccinated with type III polysaccharide of GBS were also tested. The murine-mucin-GBS model may be developed as a screening test to measure protective antibody levels in the pre- and postvaccine treatment period. The model may also be used to measure protective antibody in pooled human gamma globulin for use in the passive immunization of high-risk individuals.

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Mucin model for group B type III streptococcal infection in mice

Cited by 12 publications

References 16 publications

Protection of mice from experimental infection with type III group B Streptococcus using monoclonal antibodies.

Protection of mice from experimental infection with type III group B Streptococcus using monoclonal antibodies.

Potential Mechanisms of Mucin-Enhanced Acinetobacter baumannii Virulence in the Mouse Model of Intraperitoneal Infection

Mouse protection assay for group B streptococcus type III

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