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Antigen-presenting function of human peritoneum mesothelial cells
M T Valle1, M L Degl'Innocenti, R Bertelli
1Department of Immunology, San Martino Hospital, University of Genoa, Italy.
Abstract:
Mesothelial cells (MC) from human peritoneal omentum fragments obtained during surgical insertion of peritoneal catheters for continuous peritoneal dialysis in end stage renal failure (ESRF) patients were cultured in vitro. MC exhibited a phenotype different from macrophages, but MHC class II molecules were well expressed. Therefore MC lines were tested for antigen-presenting capacity by pulsing with soluble antigens (tetanus toxoid and purified protein derivative (PPD)) or with a corpusculate antigen (Candida albicans bodies). Autologous peripheral blood mononuclear cells (PBMC) depleted of adherent monocytes and cloned T cells generated from an individual matched for the MHC class II antigen DR2 were used to test antigen-presenting function. MC effectively presented the soluble and corpusculate antigens to autologous and MHC-compatible allogeneic lymphocytes, indicating that they are endowed with both endocytic/phagocytic activity and with processing/presenting capacity. Preincubation of MC with human recombinant interferon-gamma (IFN-gamma) up-regulated MHC class II and intercellular adhesion molecule-1 (ICAM-1) expression, but the effect on antigen-presenting function was not consistent. Since MC are an important component of the peritoneal environment, they may participate, along with macrophages, in activation of specific T cells and in the generation of local cell-mediated immunity to various pathogens.
Insights
Human mesothelial cells (MC) effectively present antigens to immune cells, suggesting a role in local immunity within the peritoneal cavity. These cells demonstrate antigen-presenting capacity, similar to macrophages, contributing to immune responses against pathogens.
Area of Science:
- Immunology
- Cell Biology
- Nephrology
Background:
- Mesothelial cells (MC) line the peritoneal cavity and play a role in immune surveillance.
- Patients with end-stage renal failure (ESRF) undergoing peritoneal dialysis have indwelling peritoneal catheters, providing access to peritoneal MC.
- The immune function of peritoneal MC, particularly their antigen-presenting capacity, is not fully understood.
Purpose of the Study:
- To investigate the antigen-presenting capacity of human peritoneal mesothelial cells (MC) in vitro.
- To determine if MC can process and present both soluble and particulate antigens to lymphocytes.
- To assess the effect of interferon-gamma (IFN-gamma) on MC antigen presentation.
Main Methods:
- Human peritoneal MC were cultured from omentum fragments of ESRF patients.
- MC were pulsed with soluble antigens (tetanus toxoid, PPD) or particulate antigens (Candida albicans).
- Antigen presentation was tested using autologous peripheral blood mononuclear cells (PBMC) and MHC-compatible allogeneic T cells.
Main Results:
- Cultured MC expressed MHC class II molecules and demonstrated effective antigen presentation of both soluble and particulate antigens.
- MC possess both endocytic/phagocytic activity and antigen processing/presenting capacity.
- IFN-gamma upregulated MHC class II and ICAM-1 on MC, but its effect on antigen presentation was inconsistent.
Conclusions:
- Human peritoneal MC possess significant antigen-presenting capabilities, comparable to macrophages.
- MC may contribute to local cell-mediated immunity in the peritoneal cavity by activating T cells.
- These findings highlight the immunological role of mesothelial cells in the peritoneal environment.