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HLA-DR regulation and the influence of GM-CSF on transcription, surface expression and shedding.

Perry SE, Mostafa SM, Wenstone R, Shenkin A, McLaughlin PJ - Int J Med Sci (2004)

Bottom Line: Results: Higher levels of shed HLA-DR were found in the plasma of septic patients compared to healthy controls.The level of HLA-DR mRNA was significantly lower in septic patients compared to healthy controls, however an increased intracellular HLA-DR expression was observed.GM-CSF was shown to regulate HLA-DR at all these levels.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Immunology, University of Liverpool, Liverpool, UK.

ABSTRACT
Low surface HLA-DR expression is a feature in sepsis. However, the mechanisms that regulate HLA-DR expression have not been elucidated. The current study investigates regulation of HLA-DR gene transcription, post transcriptional events and shedding of surface HLA-DR, as well as the regulation of HLA-DR by GM-CSF and an immunomodulatory cytokine. Plasma and PBMC were collected from septic patients and healthy volunteers. An ELISA was developed to measure soluble HLA. PCR techniques were used to determine HLA-DR mRNA levels, and flow cytometry and fluorescent microscopy were used for measurement of surface expressed and intracellular HLA-DR. Septic patients fulfilling the criteria of the American College of Chest Physicians (ACCP) for sepsis were recruited for the study (n=70). HLA-DR was measured on three consecutive days, days seven and fourteen. Patients were excluded from the study if on immunosuppressive therapy. Results: Higher levels of shed HLA-DR were found in the plasma of septic patients compared to healthy controls. The level of HLA-DR mRNA was significantly lower in septic patients compared to healthy controls, however an increased intracellular HLA-DR expression was observed. When HL-60 cells were treated with GM-CSF, gene transcription, surface expression and shedding of HLA-DR were all up-regulated. These results indicate that the mechanisms involved in the regulation of HLA-DR in sepsis include shedding of HLA-DR from the cell surface and regulation of HLA-DR gene transcription. Post-translational processing of HLA-DR was also seen to be compromised. GM-CSF was shown to regulate HLA-DR at all these levels.

No MeSH data available.


Related in: MedlinePlus

The intracellular: surface expression ratio of HLA-DR. A value above 1 shows a higher intracellular expression of HLA-DR compared to surface expression. Septic patients show a significantly higher number of PBMC expressing HLA-DR when intracellular expression is measured, compared to surface expression, p=0.01. (MFI: Median Fluorescent intensity)
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Figure 2: The intracellular: surface expression ratio of HLA-DR. A value above 1 shows a higher intracellular expression of HLA-DR compared to surface expression. Septic patients show a significantly higher number of PBMC expressing HLA-DR when intracellular expression is measured, compared to surface expression, p=0.01. (MFI: Median Fluorescent intensity)

Mentions: Intracellular HLA-DR was measured in permeabilised cells to investigate the presence of HLA-DR retained within the PBMC population. Flow cytometric measurement of HLA-DR expression in permeabilised cells measures both intracellular and surface. A comparison to the surface value allowed an estimate of intracellular versus extracellular expression of HLA-DR. Healthy controls (n=6) had lower expression of intracellular HLA-DR than septic patients. Figure 2 shows the intracellular and surface expression of HLA-DR from septic patients and healthy controls. In septic patients the intracellular expression was significantly higher than the corresponding surface expression, P=0.01. For healthy controls the level of intracellular expression was not statistically different to the surface expression, p=0.85, (paired Students T Test). Septic patients had a higher intracellular expression of HLA-DR than healthy controls.


HLA-DR regulation and the influence of GM-CSF on transcription, surface expression and shedding.

Perry SE, Mostafa SM, Wenstone R, Shenkin A, McLaughlin PJ - Int J Med Sci (2004)

The intracellular: surface expression ratio of HLA-DR. A value above 1 shows a higher intracellular expression of HLA-DR compared to surface expression. Septic patients show a significantly higher number of PBMC expressing HLA-DR when intracellular expression is measured, compared to surface expression, p=0.01. (MFI: Median Fluorescent intensity)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1074707&req=5

Figure 2: The intracellular: surface expression ratio of HLA-DR. A value above 1 shows a higher intracellular expression of HLA-DR compared to surface expression. Septic patients show a significantly higher number of PBMC expressing HLA-DR when intracellular expression is measured, compared to surface expression, p=0.01. (MFI: Median Fluorescent intensity)
Mentions: Intracellular HLA-DR was measured in permeabilised cells to investigate the presence of HLA-DR retained within the PBMC population. Flow cytometric measurement of HLA-DR expression in permeabilised cells measures both intracellular and surface. A comparison to the surface value allowed an estimate of intracellular versus extracellular expression of HLA-DR. Healthy controls (n=6) had lower expression of intracellular HLA-DR than septic patients. Figure 2 shows the intracellular and surface expression of HLA-DR from septic patients and healthy controls. In septic patients the intracellular expression was significantly higher than the corresponding surface expression, P=0.01. For healthy controls the level of intracellular expression was not statistically different to the surface expression, p=0.85, (paired Students T Test). Septic patients had a higher intracellular expression of HLA-DR than healthy controls.

Bottom Line: Results: Higher levels of shed HLA-DR were found in the plasma of septic patients compared to healthy controls.The level of HLA-DR mRNA was significantly lower in septic patients compared to healthy controls, however an increased intracellular HLA-DR expression was observed.GM-CSF was shown to regulate HLA-DR at all these levels.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Immunology, University of Liverpool, Liverpool, UK.

ABSTRACT
Low surface HLA-DR expression is a feature in sepsis. However, the mechanisms that regulate HLA-DR expression have not been elucidated. The current study investigates regulation of HLA-DR gene transcription, post transcriptional events and shedding of surface HLA-DR, as well as the regulation of HLA-DR by GM-CSF and an immunomodulatory cytokine. Plasma and PBMC were collected from septic patients and healthy volunteers. An ELISA was developed to measure soluble HLA. PCR techniques were used to determine HLA-DR mRNA levels, and flow cytometry and fluorescent microscopy were used for measurement of surface expressed and intracellular HLA-DR. Septic patients fulfilling the criteria of the American College of Chest Physicians (ACCP) for sepsis were recruited for the study (n=70). HLA-DR was measured on three consecutive days, days seven and fourteen. Patients were excluded from the study if on immunosuppressive therapy. Results: Higher levels of shed HLA-DR were found in the plasma of septic patients compared to healthy controls. The level of HLA-DR mRNA was significantly lower in septic patients compared to healthy controls, however an increased intracellular HLA-DR expression was observed. When HL-60 cells were treated with GM-CSF, gene transcription, surface expression and shedding of HLA-DR were all up-regulated. These results indicate that the mechanisms involved in the regulation of HLA-DR in sepsis include shedding of HLA-DR from the cell surface and regulation of HLA-DR gene transcription. Post-translational processing of HLA-DR was also seen to be compromised. GM-CSF was shown to regulate HLA-DR at all these levels.

No MeSH data available.


Related in: MedlinePlus