Abstract:
:Many of the virulence factors associated with fulminant group A streptococci (GAS) infection are expressed under in vitro exponential growth conditions. However, the survival of GAS in tissue and intracellularly, as well as colonization of asymptomatic carriers, has been reported for GAS. The bacteria associated with these niches may encounter high-density, low-nutrient-flowthrough conditions that may more closely mimic in vitro stationary-phase conditions than exponential growth. Therefore, the behavior of GAS in stationary-phase culture was examined. We observed that after 24 h in stationary phase, GAS serotypes M49 and M2 developed a unstable colony dimorphism of typical large and atypical small colonies. Between days 4 and 5, we isolated stabilized atypical small colonies which remained stable for up to nine passages (approximately 200 generations) on fresh medium before fully reverting to the large-colony phenotype. Upon analysis, the small colonies showed no difference in cell number per colony, growth rate, survival in prolonged stationary-phase culture, or antibiotic sensitivity. However, the small colonies showed decreased transcription of hyaluronic acid capsule, the global positive virulence factor regulator gene mga, the mga-regulated emm mRNA (M-protein structural gene), and speB (cysteine protease). Accordingly, the small colonies were completely sensitive in a traditional phagocytosis assay. The production of virulence factors and phagocytosis resistance of the small-colony isolates was recovered when, after several passages on fresh medium, the colony morphology began to revert.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Leonard BA,Woischnik M,Podbielski Adoi
10.1128/IAI.66.8.3841-3847.1998subject
Has Abstractpub_date
1998-08-01 00:00:00pages
3841-7issue
8eissn
0019-9567issn
1098-5522journal_volume
66pub_type
杂志文章abstract::It was previously determined that the type II secretion system (T2SS) promotes the ability of Legionella pneumophila to grow in coculture with amoebae. Here, we discerned the stage of intracellular infection that is potentiated by comparing the wild-type and T2SS mutant legionellae for their capacity to parasitize Aca...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00374-19
更新日期:2019-10-18 00:00:00
abstract::Intestinal mucus is postulated to play a role in preventing colonization of the gastrointestinal tract by microbial pathogens. To evaluate the ability of both crude mucus and purified mucin, a glycoprotein of goblet cell origin, to inhibit mucosal adherence of enteric pathogens, we examined whether mucus and mucin der...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.9.2437-2442.1988
更新日期:1988-09-01 00:00:00
abstract::A recombinant 23-kDa protein (rBPI23) derived from human bactericidal/permeability-increasing protein (BPI) possesses potent endotoxin-neutralizing abilities in vitro and in vivo. Binding of rBPI23 to those endotoxins (lipopolysaccharides [LPSs]) encountered clinically would be a prerequisite for efficacy in decreasin...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.8.3564-3567.1994
更新日期:1994-08-01 00:00:00
abstract::The antigenicities of Mycobacterium bovis strain BCG and an isoniazid (INH) - resistant mutant were compared. Sonic extracts of heat-killed, washed bacteria were injected into rabbits, and antisera were produced (anti-BCG and anti-BCG-R). The sonic extracts were also subjected to ultracentrifugation, and test antigens...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.3.4.524-529.1971
更新日期:1971-04-01 00:00:00
abstract::We have previously reported that a wild strain of Francisella tularensis is much less efficiently killed by human polymorphonuclear leukocytes than is an attenuated strain. In the present study, the killing of the attenuated strain was found to be strictly oxygen dependent. The wild and the attenuated strains both ind...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.43.2.730-734.1984
更新日期:1984-02-01 00:00:00
abstract::Metastatic infection after hematogenous dissemination of Candida species is presumably dependent on the fungus traversing the vascular endothelium. An in vitro model of the earliest events of metastatic Candida infection was developed with whole vascular strips. Freshly obtained porcine blood vessels were secured in a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.42.1.374-384.1983
更新日期:1983-10-01 00:00:00
abstract::Guinea pigs sensitized by repeated skin testing with potent, merthiolated coccidioidin, equal to Smith standard, exhibited erythema, edema, and an induration-like reaction to intradermal injection of the preparation. No statistically significant migration inhibition of peritoneal exudate macrophages from these animals...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.7.2.226-230.1973
更新日期:1973-02-01 00:00:00
abstract::Aspergillus species are saprophytic molds causing life-threatening invasive fungal infections in the immunocompromised host. Innate immune recognition, in particular, the mechanisms of opsonization and complement activation, has been reported to be an integral part of the defense against fungi. We have shown that the ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00032-13
更新日期:2013-05-01 00:00:00
abstract::We investigated the role of bacterial adherence and hemolysin production from Escherichia coli parent and genetically cloned strains as to their effects on histamine release from rat mast cells and leukotriene generation from human polymorphonuclear granulocytes. These mediators were involved in the induction of infla...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.50.1.271-278.1985
更新日期:1985-10-01 00:00:00
abstract::The purpose of this investigation was to examine gamma interferon potentiation of lipopolysaccharide (LPS) responses in human monocytes by using phenol-water-extracted (unfractionated) and highly purified LPS preparations isolated from Bacteroides intermedius and Salmonella typhimurium. Phenol-water-extracted LPS prep...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.59.1.398-406.1991
更新日期:1991-01-01 00:00:00
abstract::Fourteen freshly isolated strains of Streptococcus sanguis were obtained from the dental plaque of five healthy adults. Whole saliva was collected concomitant with the plaque isolates from the five subjects, and a second whole saliva sample was collected 10 weeks later. All possible combinations of the first five sali...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.26.3.1104-1110.1979
更新日期:1979-12-01 00:00:00
abstract::The purpose of the present study was to evaluate the effectiveness of an attenuated Salmonella enterica serovar Typhimurium vaccine strain expressing the saliva-binding region (SBR) of the Streptococcus mutans antigen I/II adhesin, either alone or linked with the mucosal adjuvant cholera toxin A2 and B subunits (CTA2/...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.4.2154-2161.2001
更新日期:2001-04-01 00:00:00
abstract::Staphylococcus aureus is an important pathogen of humans and other animals, causing bacteremia, abscesses, endocarditis, and other infectious syndromes. A signature-tagged mutagenesis (STM) system was adapted for use in studying the genes required for in vivo survival of S. aureus. An STM library was ultimately create...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.66.2.567-572.1998
更新日期:1998-02-01 00:00:00
abstract::Spirochetes have been implicated as potential etiologic agents of periodontitis in humans. Murine monoclonal antibodies (MAbs) specific for a serogroup of Treponema denticola, an oral spirochete, were developed and characterized in this study. Antibodies secreted by clone IAA11 were judged to be the most useful, since...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.1.60-63.1988
更新日期:1988-01-01 00:00:00
abstract::In this work we immunized mice with DNA encoding full-length Tc52 or its amino- or carboxy-terminal (N- and C-term, respectively) domain carried by attenuated Salmonella as a DNA delivery system. As expected, Salmonella-mediated DNA delivery resulted in low antibody titers and a predominantly Th1 response, as shown by...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.02190-14
更新日期:2014-10-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.31.1.487-494.1981
更新日期:1981-01-01 00:00:00
abstract::Sixty-one Burkholderia cepacia isolates from patients with cystic fibrosis (CF) and four plant isolates were screened for production of the siderophores salicylic acid (SA), pyochelin, cepabactin, and ornibactins and fingerprinted by a PCR-based randomly amplified polymorphic DNA (RAPD) method. Of the 24 RAPD types de...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.66.2.874-877.1998
更新日期:1998-02-01 00:00:00
abstract::The genetic determinants of the 120-kDa cytotoxin of Actinobacillus pleuropneumoniae serotype 2 were isolated from a lambda DNA library by a plaque immunoblot technique. Expression of the 120-kDa polypeptide was confirmed by Western immunoblot analysis of infected Escherichia coli cell lysates, which were shown to be ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.7.2726-2732.1992
更新日期:1992-07-01 00:00:00
abstract::We have previously demonstrated the existence of Klebsiella pneumoniae clinical isolates deficient in the lipopolysaccharide O side chain, the major factor for resistance to complement-mediated killing in this bacterial species. These isolates are complement resistant, and their mechanisms to resist complement were in...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.68.2.953-955.2000
更新日期:2000-02-01 00:00:00
abstract::We investigated a possible cause-and-effect relationship between sensitization against Actinomyces viscosus Nyl and destructive periodontal disease in RIC-Sprague-Dawley rats. Germfree rats (66) were either immunized with A. viscosus Nyl (day 20) or orally infected with A. viscosus Nyl (days 38 and 39) or both. We mea...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.31.3.971-977.1981
更新日期:1981-03-01 00:00:00
abstract::Immunoprecipitation of radiolabeled antigens with bovine antisera indicated that many Babesia bigemina and Babesia bovis merozoite proteins contain isolate-common epitopes, while at least 16 B. bigemina and 8 B. bovis proteins contain species-cross-reactive epitopes. One immunogenic, isolate-common, and species-specif...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.6.1658-1660.1988
更新日期:1988-06-01 00:00:00
abstract::Trypanosoma musculi produces a chronic infection with a consistently elevated parasitemia in nude mice. Thymic reconstitution of nude mice restores immunity to the infection. ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.16.2.715-716.1977
更新日期:1977-05-01 00:00:00
abstract::Streptococcus pneumoniae cell wall and pneumolysin are important contributors to pneumococcal pathogenicity in some animal models. To further explore these factors in middle ear inflammation caused by pneumococci, penicillin-induced inflammatory acceleration was studied by using three closely related pneumococcal stra...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.64.4.1140-1145.1996
更新日期:1996-04-01 00:00:00
abstract::Synthetic peptides and murine monoclonal antibodies were used to map cross-reactive chlamydial epitopes. A species-specific epitope in the central region of variable sequence region 4 abuts the amino-terminal end of a B-serogroup-specific or F/G-serogroup-specific epitope, which in turn abuts known serovar-specific ep...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.64.7.2839-2841.1996
更新日期:1996-07-01 00:00:00
abstract::Utilization of heme-hemopexin as a source of heme by Haemophilus influenzae type b is dependent on expression by this bacterium of the 100-kDa HxuA protein, which is both present on the bacterial cell surface and released into the culture supernatant (L. D. Cope, R. Yogev, U. Muller-Eberhard, and E. J. Hansen, J. Bact...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:
更新日期:1998-09-01 00:00:00
abstract::The recently introduced choleragen-induced rat foot edema model has been employed as a bioassay for evaluating the immunogenicity of three purified preparations containing cholera exo-enterotoxin antigen, choleragen, choleragenoid, and Formalin-treated choleragen (formagen). The results indicated that choleragen evoke...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.1.5.468-473.1970
更新日期:1970-05-01 00:00:00
abstract::Conjugated polysaccharide vaccines protect against serogroup C meningococci. However, this approach cannot be applied to serogroup B, which is still a major cause of meningitis. We evaluated the immunogenicity of three surface-exposed proteins from serogroup B Neisseria meningitidis (App, NhhA, and NadA) identified du...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.7.4052-4060.2004
更新日期:2004-07-01 00:00:00
abstract::Pathogenic Leptospira spp. are likely to encounter higher concentrations of reactive oxygen species induced by the host innate immune response. In this study, we characterized Leptospira interrogans catalase (KatE), the only annotated catalase found within pathogenic Leptospira species, by assessing its role in resist...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00466-12
更新日期:2012-11-01 00:00:00
abstract::Anopheles gambiae is the major African vector of Plasmodium falciparum, the most deadly species of human malaria parasite and the most prevalent in Africa. Several strategies are being developed to limit the global impact of malaria via reducing transmission rates, among which are transmission-blocking vaccines (TBVs)...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00864-06
更新日期:2007-04-01 00:00:00
abstract::Several Shigella flexneri mutants with defects in aromatic amino acid and/or purine biosynthesis have been evaluated as vaccines in humans or in animal models. To be suitable as a vaccine, a mutant has to show virulence attenuation, minimal reactogenicity, and a good immunogenic potential in animal models. With this a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.71.12.7002-7013.2003
更新日期:2003-12-01 00:00:00