scholarly journals Hemocyte Changes During Immune Melanization in Bombyx Mori Infected with Escherichia coli

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 301 ◽  
Author(s):  
Tian Li ◽  
Dengfeng Yan ◽  
Xiaohui Wang ◽  
Liang Zhang ◽  
Ping Chen
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Bombyx Mori ◽  
Circulatory System ◽  
Fourth Instar ◽  
Physiological Process ◽  
Immune Challenge ◽  
Escherichia Coli Infection ◽  
Independent Process

Hemolymph melanization is a conserved immune response in insects and other arthropods. However, the physiological process of the hemolymph system in the melanization response is hardly studied. Here, alterations of hemocytes in immune melanization were observed by Escherichia coli infection in Bombyx mori. Results first showed that there were cells aggregating into clusters. However, it vanished, and only part of clustered hemocytes were melanized during the period of intense immunity. The hemocyte numbers immediately decreased following an immune challenge, slowly increased to a peak, then reduced and finally returned to normalization. Granulocytes participated in cells aggregation at the early and later immune stage, while plasmatocytes were responsible for hemocytes agglomerate and melanization for the longest time, and more oenocytoids appeared at the peak stage of melanization. Moreover, hemocytes played a crucial role in resisting invasion of pathogens by agglomerate and melanization, and the circulatory system maintained higher hemocyte numbers and stronger antibacterial activity in fifth than fourth instar larvae after infection. In vitro immune melanization was most likely preferentially implemented in an independent process. These were the main characteristics reflecting the physiological process of hemolymph immune melanization, which provided an important foundation for further study of the complete mechanisms in the immunity of silkworm.

scholarly journals MATURATION OF THE IMMUNE RESPONSE IN VITRO

1972 ◽  
Vol 136 (2) ◽  
pp. 353-368 ◽  
Author(s):  
Alberto J. L. Macario ◽  
Everly Conway de Macario ◽  
Claudio Franceschi ◽  
Franco Celada
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Lymph Node ◽  
Association Constant ◽  
Secondary Response ◽  
Antibody Specificity ◽  
Affinity Selection ◽  
Immune Response In Vitro ◽  
Selection Of

We have cultivated lymph node microfragments from ß-D-galactosidase (Escherichia coli) primed rabbits and have measured their secondary response directed towards the whole molecule (precipitating antibodies) and to a single determinant (activating antibodies) of the antigen. By decreasing the size of the fragments to 105 cells, we began to observe heterogeneity among identical cultures in terms of positivity of response, antibody specificity, and titers. The affinity of "early" activating antibodies was inversely proportional to the dose of challenge. While no maturation was seen in low and excessive challenge, in all cultures receiving intermediate doses the association constant was raised several orders of magnitude within periods of 20 days. The relevance of these data to the mechanism of affinity selection of antigen-sensitive cells is discussed.

scholarly journals Ribonuclease 7 Shields the Kidney and Bladder from Invasive Uropathogenic Escherichia coli Infection

2019 ◽  
Vol 30 (8) ◽  
pp. 1385-1397 ◽  
Author(s):  
Tad Eichler ◽  
Kristin Bender ◽  
Matthew J. Murtha ◽  
Laura Schwartz ◽  
Jackie Metheny ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Transgenic Mice ◽  
Urothelial Cells ◽  
Bladder Urothelium ◽  
Functional Studies ◽  
Escherichia Coli Infection ◽  
Study Participants

BackgroundEvidence suggests that antimicrobial peptides, components of the innate immune response, protect the kidneys and bladder from bacterial challenge. We previously identified ribonuclease 7 (RNase 7) as a human antimicrobial peptide that has bactericidal activity against uropathogenic Escherichia coli (UPEC). Functional studies assessing RNase 7’s contributions to urinary tract defense are limited.MethodsTo investigate RNase 7’s role in preventing urinary tract infection (UTI), we quantified urinary RNase 7 concentrations in 29 girls and adolescents with a UTI history and 29 healthy female human controls. To assess RNase 7’s antimicrobial activity in vitro in human urothelial cells, we used siRNA to silence urothelial RNase 7 production and retroviral constructs to stably overexpress RNase 7; we then evaluated UPEC’s ability to bind and invade these cells. For RNase 7 in vivo studies, we developed humanized RNase 7 transgenic mice, subjected them to experimental UTI, and enumerated UPEC burden in the urine, bladder, and kidneys.ResultsCompared with controls, study participants with a UTI history had 1.5-fold lower urinary RNase 7 concentrations. When RNase 7 was silenced in vitro, the percentage of UPEC binding or invading human urothelial cells increased; when cells overexpressed RNase 7, UPEC attachment and invasion decreased. In the transgenic mice, we detected RNase 7 expression in the kidney’s intercalated cells and bladder urothelium. RNase 7 humanized mice exhibited marked protection from UPEC.ConclusionsThese findings provide evidence that RNase 7 has a role in kidney and bladder host defense against UPEC and establish a foundation for investigating RNase 7 as a UTI prognostic marker or nonantibiotic-based therapy.

scholarly journals Stability of recombinant 2 S albumin allergens in vitro

2002 ◽  
Vol 30 (6) ◽  
pp. 913-915 ◽  
Author(s):  
G. J. Murtagh ◽  
M. Dumoulin ◽  
D. B. Archer ◽  
M. J. Alcocer
Keyword(s):  
Immune Response ◽  
Circulatory System ◽  
Gastric Fluid ◽  
Low Ph ◽  
Simulated Gastric Fluid ◽  
Brazil Nut

Two well known 2 S albumins, Ber e 1 from brazil nut and sunflower 2 S albumin 8 (SFA-8), have been expressed in a eukaryotic system and purified. Analysis of recombinant versions of Ber e 1 and SFA-8 revealed them to be significantly more resistant to digestion by pepsin than BSA, and to be stable for up to 30 min in simulated gastric fluid. Unfolding monitored by CD indicated that both proteins were also very resistant to denaturation induced by heat and low pH. These results suggest that, although the ability of 2 S albumins to reach the circulatory system may be a prerequisite for the allergenicity of this group of proteins, stability is just one of a number of characteristics that provoke a selective immune response.

scholarly journals Metalloproteinases TACE and MMP-9 Differentially Regulate Death Factors on Adult and Neonatal Monocytes After Infection with Escherichia coli

2019 ◽  
Vol 20 (6) ◽  
pp. 1399 ◽  
Author(s):  
Stephan Dreschers ◽  
Christopher Platen ◽  
Andreas Ludwig ◽  
Christian Gille ◽  
Natascha Köstlin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Surface Expression ◽  
Cell Contact ◽  
Infected Adult ◽  
Escherichia Coli Infection ◽  
Factor Α ◽  
Necrosis Factor

Background: Cleaving ligands and receptors of the tumor necrosis factor (TNF) superfamily can critically regulate the induction of apoptosis. Matrix metalloproteinases (MMPs) such as MMP-9 and tumor necrosis factor-α-converting enzyme (TACE) have been shown to cleave CD95-Ligand (CD95L) and TNF/(TNF receptor-1) TNFR1 which induce phagocytosis induced cell death (PICD) in adult monocytes. This process is reduced in neonatal monocytes. Methods: Here we tested in vitro, whether Escherichia coli infection mounts for activation of MMP-9 and TACE in monocytes and whether this process regulates PICD. Results: The surface expression of TACE was most prominent on infected adult monocytes. In contrast, surface presentation of MMP-9 was highest on infected neonatal monocytes. Selective blocking of MMP-9 decreased CD95L secretion, while inhibition of TACE left CD95L secretion unaltered. Blocking of MMP-9 increased surface CD95L (memCD95L) expression on infected neonatal monocytes to levels comparable to infected adult monocytes. Moreover, MMP-9 inhibition raised PICD of infected neonatal monocytes to levels observed for infected adult monocytes. In contrast, TACE inhibition decreased PICD in infected monocytes. Addition of extracellular TNF effectively induced memCD95L presentation and PICD of adult monocytes and less of neonatal monocytes. Conclusion: MMP-9 activity is crucial for downregulating cell-contact dependent PICD in E. coli infected neonatal monocytes. By this mechanism, MMP-9 could contribute to reducing sustained inflammation in neonates.

scholarly journals Interleukin-6 is required for a protective immune response to systemic Escherichia coli infection.

1996 ◽  
Vol 64 (8) ◽  
pp. 3231-3235 ◽  
Author(s):  
S A Dalrymple ◽  
R Slattery ◽  
D M Aud ◽  
M Krishna ◽  
L A Lucian ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Interleukin 6 ◽  
Protective Immune Response ◽  
Escherichia Coli Infection
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