Abstract:
:Strategies to limit complement deposition on Streptococcus pneumoniae are established as virulence features for invasive disease, but their role in respiratory tract infection requires further analysis. We evaluated complement C3 protein deposition on discordant S. pneumoniae isolates of the same serotype (6A) and their capacity to cause nasopharyngeal (NP) colonization and experimental otitis media (EOM) in an animal model. We compared C3 binding to five 6A isolates from asymptomatic NP carriers with five 6A strains that caused invasive disease, and we observed less C3 ( approximately 10-fold less fluorescence) binding to invasive isolates. We selected two high-level C3-binding carriage and two low-level C3-binding invasive 6A isolates for further study. In the EOM model, 11/12 (92%) ears challenged with a low-level C3-binding 6A strain became infected. Only 2/8 (25%) ears challenged with the discordant high-level C3-binding 6A isolate developed disease (P = 0.005). Results with the second discordant 6A isolate pair were comparable. Cobra venom factor (CoVF) treatment, which depletes C3 and consumes complement, restored virulence of the high-level C3-binding strain; 8/8 (100%) ears in CoVF-treated animals developed EOM compared to only 25% of ears in naïve animals (P = 0.007). These studies demonstrate the critical role for complement evasion in pneumococcal EOM. Colonization with carriage isolates that bound high levels of C3 caused EOM in fewer animals compared to low-level C3-binding invasive strains. Thus, limiting C3 deposition on the surface of S. pneumoniae correlates with increased incidence of EOM following NP colonization and barotrauma in the animal model.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Sabharwal V,Ram S,Figueira M,Park IH,Pelton SIdoi
10.1128/IAI.01148-08subject
Has Abstractpub_date
2009-03-01 00:00:00pages
1121-7issue
3eissn
0019-9567issn
1098-5522pii
IAI.01148-08journal_volume
77pub_type
杂志文章abstract::We have identified a Crp/Fnr-like transcriptional regulator of Streptococcus pyogenes that when inactivated attenuates virulence. The gene, named srv for streptococcal regulator of virulence, encodes a 240-amino-acid protein with 53% amino acid similarity to PrfA, a transcriptional activator of virulence in Listeria m...
journal_title:Infection and immunity
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journal_title:Infection and immunity
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doi:10.1128/IAI.1.5.468-473.1970
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doi:10.1128/IAI.61.3.1132-1135.1993
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abstract::Depressed Th1 responses are a prominent feature of human tuberculosis, but an enhanced Th2 response has not been detected in peripheral blood T cells stimulated in vitro with Mycobacterium tuberculosis. In disease due to Mycobacterium leprae, Th2 cells predominate in tissue lesions of patients with extensive disease b...
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doi:10.1128/IAI.64.4.1351-1356.1996
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abstract::Cell-mediated immunity is pivotal in host resistance to Blastomyces dermatitidis infection. Immunization of mice with the WI-1 adhesin enhances resistance against experimental pulmonary infection but elicits features of a mixed T-helper-cell immune response. Immune mice acquire delayed-type hypersensitivity (DTH) but ...
journal_title:Infection and immunity
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abstract::To identify potential vaccine candidates for the prevention of infection with the filarial nematode Onchocerca volvulus, we screened an O. volvulus L3 stage cDNA library with sera from putatively immune (PI) subjects, and a prominent immunogenic clone of 1,184 nucleotides was identified. It contained an open reading f...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.2.851-858.2002
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abstract::This study was undertaken to ascertain the relationship between complement-derived chemotactic factors and complement component 1 inactivator (C1INA) enhancement of neutrophil chemotaxis. Studies were also designed to determine whether the C1s- reactive or binding site on C1INA was functional in altering chemotactic r...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:
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abstract::Oligosaccharides (OSs) related to the pneumococcal type 14 capsular polysaccharide (Pn14PS) were studied for their ability to inhibit the binding between anti-PS14 antisera and native PS14. A synthetic tetrasaccharide corresponding to the repeating unit of the Pn14PS, a hexasaccharide mimic, and an octasaccharide frag...
journal_title:Infection and immunity
pub_type: 杂志文章
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.65.3.1088-1094.1997
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abstract::Lipoprotein I (OprI) is one of the major proteins of the outer membrane of Pseudomonas aeruginosa. OprI is a candidate for a vaccine against P. aeruginosa, because it cross-reacts antigenically in all serotype strains of the International Antigenic Typing Scheme. We recently cloned and expressed the gene coding for Op...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.58.7.2241-2244.1990
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abstract::Human gamma delta T cells are known to respond at high frequencies to pathogenic mycobacteria. Here we show that opportunistic strains of mycobacteria share with pathogenic mycobacteria the ability to trigger at high frequencies human V gamma 9V delta 2 T-cell-receptor-positive T lymphocytes. Stimulating ligands were ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.7.2753-2757.1992
更新日期:1992-07-01 00:00:00
abstract::Patients that have suffered a major injury may sustain a period of immunocompromise and altered Th1/Th2 cytokine balance that can predispose them to opportunistic infections. Pseudomonas aeruginosa is frequently a causative organism for nosocomial infections in critically ill patients and is associated with high morta...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.12.6892-6901.2004
更新日期:2004-12-01 00:00:00
abstract::Upon infection of a host, the pathogenic fungus Aspergillus fumigatus is attacked by the reactive oxygen species produced by phagocytic cells. Detoxification of hydrogen peroxide by catalases was proposed as a way to overcome this host response. A. fumigatus produces three active catalases; one is produced by conidia,...
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pub_type: 杂志文章
doi:10.1128/iai.71.6.3551-3562.2003
更新日期:2003-06-01 00:00:00
abstract::Survival of macrophage microbicidal activity is a prerequisite for invasive disease caused by the enteric pathogen Salmonella enterica serovar Typhimurium. Flavohemoglobins, such as those of Escherichia coli, Salmonella, and yeast, play vital roles in protection of these microorganisms in vitro from nitric oxide (NO) ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.8.4399-4405.2002
更新日期:2002-08-01 00:00:00
abstract::Mycoplasma hyorhinis organisms were fractionated into lipid, carbohydrate, and protein fractions by chemical and physiochemical procedures. When all fractions were tested for complement fixation and inhibition of growth inhibition activity, only the protein fractions possessed activity. Thus, it appears that the major...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.7.6.937-940.1973
更新日期:1973-06-01 00:00:00
abstract::Group A streptococci of M protein type 5 have been epidemiologically related to acute rheumatic fever in a number of reported outbreaks. Preliminary bacteriological evidence suggests that M5 may be an important "rheumatogenic" type in Santiago, Chile. To assess further the relationship of this streptococcal serotype t...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.38.2.573-579.1982
更新日期:1982-11-01 00:00:00
abstract::The effects of pathologically relevant concentrations (0.38 to 12.5 microM) of the proinflammatory, Pseudomonas aeruginosa-derived pigment 1-hydroxyphenazine (1-hp) on Ca2+ metabolism and intracellular cyclic AMP (cAMP) in N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP; 1 microM)-activated human neutrophils, as w...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.67.10.5157-5162.1999
更新日期:1999-10-01 00:00:00
abstract::Hemolytic-uremic syndrome (HUS) results from infection by Shiga toxin (Stx)-producing Escherichia coli and is the most common cause of acute renal failure in children. We have developed a mouse model of HUS by administering endotoxin-free Stx2 in multiple doses over 7 to 8 days. At sacrifice, moribund animals demonstr...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00592-08
更新日期:2008-10-01 00:00:00
abstract::High levels of Treponema denticola in subgingival dental plaque are associated with severe periodontal disease. T. denticola, along with Porphyromonas gingivalis and Bacteroides forsythus, are the only cultivatable oral microorganisms that produce significant amounts of "trypsin-like" peptidase activity. The ability o...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.10.6193-6200.2001
更新日期:2001-10-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.9.3930-3936.1994
更新日期:1994-09-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.06224-11
更新日期:2012-12-01 00:00:00
abstract::Lysogenic conversion of Shigella flexneri type antigens was studied with the aid of wild-type and thermosensitive mutant phages. With all wild-type phages, the appearance of glycosylated antigen was accompanied by the appearance of polyprenyl phosphate glucose synthetase activity. With some of the mutant phages, the a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.14.6.1290-1292.1976
更新日期:1976-12-01 00:00:00
abstract::Two extremely oxygen-sensitive strains of Clostridium sp., designated Clostridium E and P, were obtained from digestive microflora of conventional mice and found to constitute a barrier against Shigella flexneri SF-2 when associated in vivo with Escherichia coli K-12. These and other simplified fractions of the conven...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.17.2.415-424.1977
更新日期:1977-08-01 00:00:00
abstract::Toxoplasma gondii and Neospora caninum (both Apicomplexa) are closely related cyst-forming coccidian parasites that differ significantly in their host ranges and ability to cause disease. Unlike eutherian mammals, Australian marsupials (metatherian mammals) have long been thought to be highly susceptible to toxoplasmo...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00173-17
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.64.3.980-986.1996
更新日期:1996-03-01 00:00:00
abstract::Chronic helminth infections are known to be associated with the modulation of antigen-specific T-cell responses. Strongyloides stercoralis infection is characterized by the downmodulation of antigen-specific Th1 and Th17 responses and the upregulation of Th2 and Th9 responses. Immune homeostasis is partially maintaine...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00469-19
更新日期:2019-11-18 00:00:00
abstract::Francisella tularensis is a facultative intracellular bacterial pathogen and the causative agent of tularemia. After infection of macrophages, the organism escapes from its phagosome and replicates to high density in the cytosol, but the bacterial factors required for these aspects of virulence are incompletely define...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00822-12
更新日期:2013-03-01 00:00:00
abstract::Bordetella bronchiseptica is a Gram-negative bacterium that infects and causes disease in a wide variety of animals. B. bronchiseptica also infects humans, thereby demonstrating zoonotic transmission. An extensive characterization of human B. bronchiseptica isolates is needed to better understand the distinct genetic ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01453-13
更新日期:2014-04-01 00:00:00
abstract::It has been shown previously that serum from chronically infected patients with cystic fibrosis inhibits the phagocytosis of Pseudomonas aeruginosa by both normal and cystic fibrosis alveolar macrophages. In the present study, the ability of peripheral monocytes and polymorphonuclear leukocytes from normal volunteers ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.38.2.802-805.1982
更新日期:1982-11-01 00:00:00
abstract::The purpose of this study was to determine the effects of human monocytes, macrophages, and polymorphonuclear neutrophils (PMN) on the fungal pathogen Blastomyces dermatitidis in vitro. Peripheral blood monocyte monolayers significantly inhibited the replication of a virulent strain (V) and an avirulent strain (AV) of...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.36.1.297-303.1982
更新日期:1982-04-01 00:00:00