Potencial de peptidases extraídas do látex da Calotropis procera como agente imunoterápico contra Salmonella ssp

Abstract

Proteases isolated from the latex of the medicinal plant of Calotropis procera have been investigated in different models of inflammation. Considering previous studies that indicated anti-inflammatory properties of a mixture of proteases called LPp2, in this work, a mixture of proteases called LPp3 was investigated in an experimental salmonellosis model. Thus, macrophage cultures were exposed to different concentrations of LPp3 and infected with Salmonella enterica Sor. Typhimurium. In another infection model, Swiss mice were infected intraperitoneally with S. Typhimurium and then treated (intravenously) with LPp3. The results showed that LPp3 has no direct antibacterial action against Salmonella in vitro and was unable to increase the cell viability of infected macrophages. In the in vivo assays, after 6 h of infection, animals treated with LPp3 (10 mg/kg) had a higher bacterial load in the spleen and liver compared to untreated control (PBS) or Dexamethasone-administered groups. Treatments with LPp3 (1, 5 and 10 mg/kg) inhibited the recruitment of leukocytes to the infectious site after Salmonella inoculum in the peritoneal cavity. However, gene expression levels of inflammatory cytokines measured in the spleen, such as TNF-alpha and IL1-beta, were significantly increased in animals treated with 10 mg/kg relative to infected/untreated animals. It was concludedthat LPp3, as already demonstrated for LPp2, is rich in enzymes with strong anti-inflammatory action, which could explain the lower elimination of bacteria at higher doses.