Related Experiment Video
Updated: Jun 28, 2026
On-Chip Endothelial Inflammatory Phenotyping
Published on: July 21, 2012
Evaluation of CD86/CD28 and CD40/CD154 pathways in regulating monocyte-derived CD80 expression during their
Insights
Monocyte-derived CD80 expression on the cell surface is upregulated in the presence of T cells during immune responses. This upregulation is independent of CD86/CD28 and CD40/CD154 pathways, suggesting novel therapeutic targets for allograft transplantation.
Area of Science:
- Immunology
- Cell Biology
Background:
- Monocytes play a crucial role in immune responses, particularly in allogeneic settings.
- CD80 is a key costimulatory molecule involved in T cell activation.
- Understanding the regulation of monocyte-derived CD80 is vital for managing immune responses, such as in transplantation.
Purpose of the Study:
- To investigate the role of monocyte-derived CD80 in costimulating CD4+ T cells.
- To determine if CD86/CD28 and CD40/CD154 pathways regulate monocyte-derived CD80 expression during allogeneic immune responses.
Main Methods:
- Co-culture of human endothelial cells (EC) with purified monocytes, with or without CD4+ cells.
- Analysis using real-time quantitative polymerase chain reaction (RT-PCR) and fluorescence-activated cell scanning (FACS).
- Evaluation of lymphocyte proliferation using mixed lymphocyte-EC reaction (MLER) with costimulation blockade.
Main Results:
- EC-stimulated monocytes showed increased CD80 transcripts without T cells, but no surface expression.
- Surface CD80 expression on monocytes was restored in the presence of CD4+ T cells.
- Blockade of CD86/CD28 and CD40/CD154 pathways did not inhibit monocyte-derived CD80 upregulation.
Conclusions:
- Monocyte-derived CD80 surface expression is upregulated by T cells via a pathway independent of CD86/CD28 and CD40/CD154.
- CD80 blockade partially inhibited T cell proliferation, indicating its costimulatory role.
- Targeting monocyte activation pathways may be necessary for successful allograft transplantation.
Abstract:
This study was designed to examine the role of monocyte-derived CD80 in providing costimulation to CD4+ cells, and to determine whether monocyte-derived CD80 expression is regulated by CD86/CD28 and CD40/CD154 pathways during allogeneic immunoresponses. Human endothelial cells (EC) and purified monocytes cocultured with or without CD4+ cells were analyzed by real-time quantitative polymerase chain reaction (RT-PCR) and florescence-activated cell scanning (FACS). Peripheral blood mononuclear cells (PBMC)-EC cocultures with or without costimulation blockade were analyzed by FACS. The effects of CD154 and CD28 blockade to inhibit lymphocyte proliferation were evaluated by mixed lymphocyte-EC reaction (MLER). RT-PCR demonstrated upregulation of CD80 transcripts in EC-stimulated monocytes in the absence of CD4+ cells. However, the surface expression of CD80 was undetectable. The expression of CD80 was restored in the presence of CD4+ cells. Additionally, CD80 blockade partially inhibited CD4+ cell proliferation induced by EC-conditioned monocytes. Monocytes demonstrated upregulation of CD80 on the surface during PBMC-EC interaction. CD86, CD28, and CD154 blockade did not prevent upregulation of monocyte-derived CD80 expression. CD28 and CD154 blockade partially inhibited lymphocyte proliferation of MLER. In summary, EC-stimulated monocytes upregulated CD80 expression at the transcript level but not on their surface in the absence of T cells. The surface expression of monocyte-derived CD80 is upregulated on EC-stimulated monocytes in the presence of T cells. CD154/CD40 and CD28/CD86 blockade cannot prevent monocyte-derived CD80 expression, suggesting that CD80 upregulation is through a CD154- or CD86-independent pathway. Specific therapy to prevent monocyte activation may be required for successful allograft transplantation.
