Latex protein extracts from Calotropis procera with immunomodulatory properties protect against experimental infections with Listeria monocytogenes

详细信息    查看全文

• 作者：Danielle Cristina de Oliveira Nascimento^a ; Maria Taciana Ralph^a ; Jacqueline Ellen Camelo Batista^a ; Diogo Manoel Farias Silva^b ; Manoel Adriã ; o Gomes-Filho^b ; Nylane Maria Alencar^c ; Nilma Cintra Leal^d ; Má ; rcio Viana Ramos^e ; Jose Vitor Lima-Filho^a ; ^{jvitor@db.ufrpe.br" class="auth_mail" title="E-mail the corresponding author} ; ^{jvitormlf@yahoo.com.br" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Laticifer fluid ; Experimental infections ; Cytokines ; Intracellular infection
• 刊名：Phytomedicine
• 出版年：2016
• 出版时间：15 June 2016
• 年：2016
• 卷：23
• 期：7
• 页码：745-753
• 全文大小：2565 K

文摘

The latex from the medicinal plant Calotropis procera is often used in folk medicine against infectious and inflammatory diseases.

Purpose

In this study, we investigate a protein fraction with immunomodulatory properties, named LP_PI, against experimental infections, in vitro and in vivo, with a virulent strain of Listeria monocytogenes.

Study design

LP_PI was exposed to cultured macrophages or Swiss mice and then challenged with L. monocytogenes.

Methods

Peritoneal macrophages were obtained from Swiss mice, and cultured in 96-well microplates. Soluble latex proteins (LP) were subjected to fractionation by ion-exchange chromatography. The major peak (LP_PI) was added into wells at 10 or 100 µg/ml. Albumin (100 µg/ml) was used for comparison between protein treatments. After incubation for 1 h at 5% CO₂/ 37°C, the supernatant was discarded and 0.2 ml of L. monocytogenes overnight culture was added in the wells. Following 4 h and 24 h infection, the cytokine mRNA expression was evaluated as well as the number of intracellular colony forming units. Swiss mice (n = 16) were injected intraperitoneally (i.p.) with LP_PI (5 and 10 mg/kg) while the control mice received albumin (10 mg/kg) or LP (10 mg/kg). After 24 h, all animal groups were challenged with L. monocytogenes (10⁶ CFU/ ml), also by i.p. route.

Results

LP_PI was not toxic to uninfected macrophages (pMØ) and significantly increased mRNA expression of TNF-α, IL-6, IL-1β and iNOS. Following infection, cell viability was reduced by 50% in albumin-treated pMØ (control); but only 17% in pMØ treated with LP_PI at 100 µg/ml. In this case, LP_PI increased expression of TNF-α and IL-6 whereas the number of bacterial colony-forming units was reduced 100-fold in comparison to control groups. Swiss mice pretreated with LP_PI showed dose-dependent survival rates that reached 80%, while mice that received albumin died 1–3 days after infection. After 24 h infection, leukocyte migration to the infectious foci was high in LP_PI-treated mice whereas the number of viable bacteria in the peritoneal fluid, liver and bloodstream were significantly reduced.

Conclusion

We conclude that LP_PI present immunomodulatory properties that are beneficial for prevention of systemic bacterial infections caused by the intracellular bacteria L. monocytogenes.