Heat-Shock Protein 60-Reactive CD4 ⁺ CD28 ^null T Cells in Patients With Acute Coronary Syndromes

Abstract

Background-CD4ϩ CD28 null T cells are present in increased numbers in the peripheral blood of patients with acute coronary syndrome (ACS) compared with patients with chronic stable angina (CSA). The triggers of activation and expansion of these cells to date remain unclear. Methods and Results-Twenty-one patients with ACS and 12 CSA patients with angiographically confirmed coronary artery disease and 9 healthy volunteers were investigated. Peripheral blood leukocytes were stimulated with human cytomegalovirus (HCMV), Chlamydia pneumoniae, human heat-shock protein 60 (hHSP60), or oxidized LDL (ox-LDL). CD4 ϩ CD28 null cells were separated by flow cytometry and assessed for antigen recognition using upregulation of interferon-␥ and perforin mRNA transcription as criteria for activation. CD4ϩ CD28 null cells from 12 of 21 patients with ACS reacted with hHSP60. No response was detected to HCMV, C pneumoniae, or ox-LDL. Incubation of the cells with anti-MHC class II and anti-CD4 antibodies but not anti-class I antibodies blocked antigen presentation, confirming recognition of the hHSP60 to be via the MHC class II pathway. Patients with CSA had low numbers of CD4 ϩ CD28 null cells. These cells were nonreactive to any of the antigens used. Circulating CD4 ϩ CD28 null cells were present in 5 of the 9 healthy controls. None reacted with hHSP60. Conclusions-We have shown that hHSP60 is an antigen recognized by CD4ϩ CD28 null T cells of ACS patients. Endothelial cells express hHSP60 either constitutively or under stress conditions. Circulating hHSP60-specific CD4 ϩ CD28 null cells may, along other inflammatory mechanisms, contribute to vascular damage in these patients.

Differential Pathways Govern CD4+CD28− T Cell Proinflammatory and Effector Responses in Patients with Coronary Artery Disease

“…These T cells differ from classic CD4 ϩ CD28 ϩ T cells regarding gene expression and function, including their ability to produce high levels of IFN-␥ and perforin (5)(6)(7). CD4 ϩ CD28 Ϫ cells, alongside other proinflammatory mechanisms, are therefore considered to play an important role in the events leading to coronary artery plaque destabilization (8).…”

“…ϩ CD28 Ϫ cells were reactive to autologous human heat shock protein (hHSP)60, prompting IFN-␥ and perforin responses on exposure to target cells pulsed with this Ag (7). In this study, we present a comprehensive investigation into the pathways instigating these responses using CD4 ϩ CD28 Ϫ clones and analyzing the role of KIR2DS2 and other activating KIRs in killing hHSP60-presenting autologous cells.…”

“…PBMCs were separated by Lymphoprep (Nycomed), and hHSP60 stimulation was conducted, as we previously described (7). CD4 ϩ CD28 Ϫ and CD4 ϩ CD28 ϩ fractions were then separated either magnetically using MACS CD4 ϩ isolation kit on LS and MS columns, according to the manufacturer's instructions (Miltenyi Biotec), or by FACS sorting, as we previously described (7).…”

“…CD4 ϩ CD28 Ϫ and CD4 ϩ CD28 ϩ fractions were then separated either magnetically using MACS CD4 ϩ isolation kit on LS and MS columns, according to the manufacturer's instructions (Miltenyi Biotec), or by FACS sorting, as we previously described (7). Cellular RNA was then extracted from each fraction using the TRIzol reagent, followed by cDNA synthesis with Superscript II reverse transcriptase and random hexamers (Life Technologies) (7).…”

Erratum: Inflammatory processes in cardiovascular disease: a route to targeted therapies

“…However, the higher systemic frequency of activated T lymphocytes in patients with AMI compared with those with stable angina 53,54 suggests that the adaptive immune system is also activated. In particular, CD4 + CD28 null T-effector cells are increased in the peripheral blood of patients after AMI 55 , and release proinflammatory cytokines (such as interferon-γ), activating monocytes and tissue macrophages, with the level of increase positively correlated with the risk of future acute coronary events 56 . Conversely, CD4 + CD25 + regulatory T cells (T REG ) release anti-inflammatory cytokines, such as IL-10.…”