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Updated: Oct 18, 2025
High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages
Published on: August 11, 2014
Immunomodulatory Responses of Two Synthetic Peptides against Salmonella Typhimurium Infection
Marco Antonio Ibarra-Valencia1, Gerardo Pável Espino-Solis2, Blanca Elisa Estrada2
1Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, A.P. 510-3, Cuernavaca 62250, Mexico.
Abstract:
In vitro assays of phagocytic activity showed that the peptide Pin2[G] stimulates phagocytosis in BMDM cells from 0.15 to 1.25 μg/mL, and in RAW 264.7 cells at 0.31 μg/mL. In the same way, the peptide FA1 induced phagocytosis in BMDM cells from 1.17 to 4.69 μg/mL and in RAW 264.7 cells at 150 μg/mL. Cytokine profiles of uninfected RAW 264.7 showed that Pin2[G] increased liberation TNF (from 1.25 to 10 μg/mL) and MCP-1 (10 μg/mL), and FA1 also increased the release of TNF (from 18.75 to 75 μg/mL) but did not increase the liberation of MCP-1. In RAW 264.7 macrophages infected with Salmonella enterica serovar Typhimurium, the expression of TNF increases with Pin2[G] (1.25-10 μg/mL) or FA1 (18.75-75 μg/mL). In these cells, FA1 also increases the expression of IL-12p70, IL-10 and IFN-γ when applied at concentrations of 37.5, 75 and 150 μg/mL, respectively. On the other hand, stimulation with 1.25 and 10 μg/mL of Pin2[G] promotes the expression of MCP-1 and IL-12p70, respectively. Finally, peptides treatment did not resolve murine gastric infection, but improves their physical condition. Cytokine profiles showed that FA1 reduces IFN-γ and MCP-1 but increases IL-10, while Pin2[G] reduces IFN-γ but increases the liberation of IL-6 and IL-12p70. This data suggests a promising activity of FA1 and Pin2[G] as immunomodulators of gastric infections in S. Typhimurium.
Insights
The peptides Pin2[G] and FA1 stimulate phagocytosis and modulate cytokine release in macrophages, suggesting potential as immunomodulators for gastric infections caused by Salmonella Typhimurium, though they did not resolve infection in mice.
Area of Science:
- Immunology
- Microbiology
- Pharmacology
Background:
- Gastric infections caused by Salmonella Typhimurium pose a significant health challenge.
- Understanding the host immune response and identifying novel immunomodulatory agents are crucial for effective treatment.
- Peptides are being explored for their therapeutic potential in infectious diseases.
Purpose of the Study:
- To investigate the immunomodulatory effects of peptides Pin2[G] and FA1 in vitro and in vivo.
- To assess the impact of these peptides on phagocytic activity and cytokine production in macrophages.
- To evaluate the efficacy of Pin2[G] and FA1 in a murine model of Salmonella Typhimurium gastric infection.
Main Methods:
- In vitro phagocytosis assays using Bone Marrow-Derived Macrophages (BMDM) and RAW 264.7 cells.
- Cytokine profiling (TNF, MCP-1, IL-12p70, IL-10, IFN-γ, IL-6) in uninfected and infected RAW 264.7 macrophages stimulated with peptides.
- In vivo assessment of peptide treatment in a murine model of Salmonella Typhimurium gastric infection, monitoring physical condition and cytokine profiles.
Main Results:
- Pin2[G] and FA1 stimulated phagocytosis in BMDM and RAW 264.7 cells at specific concentrations.
- Both peptides modulated cytokine release, with Pin2[G] increasing TNF, MCP-1, IL-6, and IL-12p70, and FA1 increasing TNF, IL-12p70, IL-10, and IFN-γ.
- While peptides did not resolve murine gastric infection, they improved the physical condition of infected mice. FA1 reduced IFN-γ and MCP-1 but increased IL-10; Pin2[G] reduced IFN-γ but increased IL-6 and IL-12p70.
Conclusions:
- Peptides Pin2[G] and FA1 exhibit immunomodulatory activities by enhancing phagocytosis and altering cytokine profiles.
- These peptides show promise as therapeutic agents for managing gastric infections caused by Salmonella Typhimurium.
- Further research is warranted to optimize peptide-based therapies for infectious diseases.
