Download Anti-Viral Immunity in Coronary Heart Disease

Anti-Viral Immunity in Coronary Heart Disease
Santosh Murali1, Evgeniya Shmeleva2, Stephen Boag2, Jedrzej Hoffmann2, Ioakim Spyridopoulos2, Stephen Todryk1
1Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
2 Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE13BZ.
ABSTRACT
(CMV+),
Infection with cytomegalovirus (CMV), as indicated by CMV seropositivity
is
associated with increased incidence of coronary heart disease (CHD). It is believed that
CMV-specific T cells in CMV+ individuals may be highly stimulated and adhere to the
diseased blood vessels, especially during infection, ischemia and therapeutic reperfusion.
This project aims to characterize T cell responses in patients with CHD during an episode of
myocardial ischemia followed by reperfusion treatment at the Freeman Hospital, Newcastle
upon Tyne. CMV positive patients showed a greater fall in the concentration of terminally
differentiated CD8+ effector memory cells in peripheral blood compared to CMV- patients,
and this fall persisted for 3 months. The cells that reduced in number were specific for CMV,
secreted the pro-inflammatory cytokine gamma interferon, and possessed the programmed
cell death (PD-1) marker. Cells that subsequently recovered in circulation showed further
sings of exhaustion and senescence such as shorter Telomere length. These findings suggest a
need to develop therapeutics to reduce CMV infection, or its consequences, in patients with
CHD.
RESULTS
Fig.1Th1 helper cells are associated with CMV seropositivity but not the
Th2 and Th17 helper cells.
Fig.4 Among all the CD8 T cell subsets, the CD8
effector memory T cell expressing CD45RA (TEMRA)
showed the most decline in cell numbers in MI patients
after reperfusion. The CMV seropositive patients
showed a 3 fold drop in cell numbers than CMV
seronegative patients 30 minutes after reperfusion.
Fig.5The CD8 T cells expressing
high levels of PD-1 showed a
significant decrease in cell number
at 90 minutes post reperfusion.
METHODS
•
AIMS
•
•
•
To measure T cell
responses in patients
with
MI
receiving
treatment.
Compare
immune
responses at different
time points.
Examine T cell in terms
of
memory
and
exhaustion.
•
•
•
ELIspot- ex-vivo enzyme linked immunospot
assay was carried out to measure cytokine
produced by T cells stimulated with specific
antigens
ELISA- enzyme linked immunosorbent assay
was carried out to measure serum antibody
levels(IgG) in patient samples.
MSD- Mesoscale Discovery- a highly
sensitive ELISA that allows the measurement
of serum antibody levels of multiple cytokines.
Flow Cytometry- 8 colour flow cytometry
was used to study T cell apoptosis studies.
Fig. 2 The serum concentration of IFN-γ (pg/ml) measured in 15 patients
by MSD was significantly higher in CMV seropositive patients than in
CMV seronegative patients at all the time points.
Fig.7 The telomere length shortening was highest in
CD8 T cells due to the fact that these senescent lack the
costimulatory receptor CD28.
CONCLUSION
Schematic Representation
of ELIspot
Schematic Representation of
ELISA
Fig.3 The magnitude of Th1 cell response measured by the spot forming
cell/million (SFC/M) positively correlated with the total ischemic time
(r=0.87) in CMV seronegative patients but negatively correlated with
CMV seropositive patients (r=0.17).
Fig.6 There was a marked
decrease in percentage of late
apoptosis in cells with the PD-1
Block compared to the cells
cultured with no PD-1 block
which along with the earlier
results clearly indicate that hyperexpressed PD-1 on activated CD8
T cells lead to the apoptosis and
permanent loss of the CD8 T
cells.
1.
2.
3.
CD8 lymphocytes temporarily decrease by >40% in the
peripheral blood after reopening of the blocked coronary
artery in patients with acute myocardial infarction.
CD8 memory lymphocytes that are directed against
cytomegalovirus are selectively depleted from the blood
for >24 hours, most probably because of programmed
cell death (apoptosis) via programmed cell death-1
signaling.
This triggers reconstitution of cytomegalovirus-specific
cells, accelerates immunosenescence and leads to
reduced telomere length.
REFERENCES
•
•
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Hoffmann, J., et al. (2015). "Myocardial Ischemia and Reperfusion Leads to Transient CD8 Immune Deficiency and Accelerated Immunosenescence in CMV-Seropositive Patients." Circulation
research 116(1): 87-98
Shmeleva, E. V., et al. (2015). "Differences in immune responses between CMV‐seronegative and‐seropositive patients with myocardial ischemia and reperfusion." Immunity, Inflammation and
Disease.
Spyridopoulos, I., et al. (2009). "Accelerated Telomere Shortening in Leukocyte Subpopulations of Patients With Coronary Heart Disease Role of Cytomegalovirus Seropositivity." Circulation
120(14): 1364-1372.