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Background: The osmotin from the medicinal plant Calotropis procera (CpOsm) has characteristics similar to adiponectin, a human protein with immunoregulatory actions., Purpose: This study aimed to investigate whether recombinant osmotin inclusion bodies from C. procera (IB/rCpOsm) produced in E. coli BL21(DE3) can prevent infection-induced inflammation. A virulent strain of Listeria monocytogenes was used as an infection model., Methods: Cells of E. coli BL21(DE3) carrying the plasmid pET303-CpOsm were used to express the recombinant osmotin, which accumulated at reasonable levels as inclusion bodies (IB/rCpOsm). IB/rCpOsm were purified from induced cells and SDS-polyacrylamide gel electrophoresis followed by mass spectrometry analyses confirmed the identity of the major protein band (23 kDa apparent molecular mass) as CpOsm. Peritoneal macrophages (pMØ) from Swiss mice were cultured with IB/rCpOsm (1 or 10 µg/ml) in 96-well plates and then infected with L. monocytogenes. IB/rCpOsm (0.1, 1 or 10 mg/kg) was also administered intravenously to Swiss mice, which were then infected intraperitoneally with L. monocytogenes., Results: Pretreatment of the pMØ with IB/rCpOsm significantly increased cell viability after infection and reduced the intracellular bacterial load. The infiltration of neutrophils into the peritoneal cavity of mice pretreated with IB/rCpOsm at 10 mg/kg (but not 0.1 and 1 mg/kg) was reduced after infection. In these mice, the bacterial load was high in the peritoneal fluid and the liver, but histological damage was discrete. The treatments with IB/rCpOsm at 10 mg/kg significantly increased the expression of the anti-inflammatory cytokine IL-10., Conclusion: This study shows that recombinant osmotin inclusion bodies from C. procera were bioactive and prompted anti-inflammatory actions at therapeutic dosages in the L. monocytogenes infection model., (Copyright © 2022. Published by Elsevier GmbH.)

Background: The lectin from Cratylia argentea (CFL) is able to modulate the immune system response and is thus a potential phytotherapeutic substance., Hypothesis/purpose: In this study, we investigated the role of CFL on control of bacterial infection caused by Listeria monocytogenes, the causative agent of human listeriosis., Study Design: Swiss mice were infected with L. monocytogenes and then treated with CFL., Methods: Adult Swiss mice weighing with 30-40 g were infected intraperitoneally with a bacterial suspension (0.2 ml; 1 × 10 7 CFU/ml). After 30 min, the mice were treated with CFL intravenously at concentrations of 0.1 or 10 mg/kg. Control mice received phosphate-buffered saline (PBS). The animals were euthanized 24 h after infection., Results: We observed that i.v. administration of CFL to Swiss mice did not cause acute toxicity, and reduced the leukocyte counts in the bloodstream 24 h after infection with virulent L. monocytogenes. There was a reduction in the bacterial burden within peritoneal macrophages after infection in CFL-treated mice. Accordingly, the bacterial counts in the bloodstream, spleen and liver also decreased in comparison with the PBS group. Histological damage in the spleen and liver was lower in mice that received CFL treatment. In vitro antimicrobial assays demonstrated that CFL does not inhibit the growth of L. monocytogenes. The mRNA expression of the anti-inflammatory cytokine IL-10 was enhanced with CFL treatment after infection., Conclusion: The lectin from C. argentea (CFL) has immunomodulatory and anti-infective properties of pharmacological interest for control of infectious diseases., (Copyright © 2021 Elsevier GmbH. All rights reserved.)