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.

Purpose: There are a significant number of patients with asymptomatic hormone-resistant prostate cancer who have increasing prostate-specific antigen (PSA) levels but little or no evaluable disease. The immunogenicity and minimal toxicity associated with cell-based vaccine therapy makes this approach attractive for these patients. Experimental Design:We have evaluated a vaccine comprising monthly intradermal injection of three irradiated allogeneic prostate cell lines (8 Â 10 6 cells each) over 1year. The first two doses were supplemented with bacille Calmette-Gue¤ rin as vaccine adjuvant. Twenty-eight hormoneresistant prostate cancer patients were enrolled. Patients were assessed clinically and PSA levels were measured monthly. Radiologic scans (X-ray, computed tomography, and bone scan) were taken at baseline and at intervals throughout the treatment period. Comprehensive monthly immunologic monitoring was undertaken including proliferation studies, activation markers, cytokine protein expression, and gene copy number. This longitudinal data was analyzed through predictive modeling using artificial neural network feed-forward/back-propagation algorithms with multilayer perceptron architecture. Results: Eleven of the 26 patients showed statistically significant, prolonged decreases in their PSA velocity (PSAV). None experienced any significant toxicity. Median time to disease progression was 58 weeks, compared with recent studies of other agents and historical control values of around 28 weeks. PSAV-responding patients showed a titratable T H 1 cytokine release profile in response to restimulation with a vaccine lysate, while nonresponders showed a mixed T H 1 and T H 2 response. Furthermore, immunologic profile correlated with PSAV response by artificial neural network analysis. We found predictive power not only in expression of cytokines after maximal stimulation with phorbol 12-myristate 13-acetate, but also the method of analysis (qPCR measurement of IFN-g > qPCR measurement tumor necrosis factor-a > protein expression of IFN-g