The use of peptide–human histocompatibility leukocyte antigen (HLA) class I tetrameric complexes to identify antigen-specific CD8+ T cells has provided a major development in our understanding of their role in controlling viral infections. However, questions remain about the exact function of these cells, particularly in HIV infection. Virus-specific cytotoxic T lymphocytes exert much of their activity by secreting soluble factors such as cytokines and chemokines. We describe here a method that combines the use of tetramers and intracellular staining to examine the functional heterogeneity of antigen-specific CD8+ T cells ex vivo. After stimulation by specific peptide antigen, secretion of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1β, and perforin is analyzed by FACS® within the tetramer-positive population in peripheral blood. Using this method, we have assessed the functional phenotype of HIV-specific CD8+ T cells compared with cytomegalovirus (CMV)-specific CD8+ T cells in HIV chronic infection. We show that the majority of circulating CD8+ T cells specific for CMV and HIV antigens are functionally active with regards to the secretion of antiviral cytokines in response to antigen, although a subset of tetramer-staining cells was identified that secretes IFN-γ and MIP-1β but not TNF-α. However, a striking finding is that HIV-specific CD8+ T cells express significantly lower levels of perforin than CMV-specific CD8+ T cells. This lack of perforin is linked with persistent CD27 expression on HIV-specific cells, suggesting impaired maturation, and specific lysis ex vivo is lower for HIV-specific compared with CMV-specific cells from the same donor. Thus, HIV-specific CD8+ T cells are impaired in cytolytic activity.

ContextThe worldwide epidemic of diabetes mellitus is increasing the burden of cardiovascular disease, the leading cause of death among persons with diabetes. The independent effect of diabetes on mortality following acute coronary syndromes (ACS) is uncertain.Objective To evaluate the influence of diabetes on mortality following ACS using a large database spanning the full spectrum of ACS. Design, Setting, and PatientsA subgroup analysis of patients with diabetes enrolled in randomized clinical trials that evaluated ACS therapies. Patients with ACS in 11 independent Thrombolysis in Myocardial Infarction (TIMI) Study Group clinical trials from 1997 to 2006 were pooled, including 62 036 patients (46 577 with ST-segment elevation myocardial infarction [STEMI] and 15 459 with unstable angina/ non-STEMI [UA/NSTEMI]), of whom 10 613 (17.1%) had diabetes. A multivariable model was constructed to adjust for baseline characteristics, aspects of ACS presentation, and treatments for the ACS event.Main Outcome Measures Mortality at 30 days and 1 year following ACS among patients with diabetes vs patients without diabetes.

We developed an AIDS vaccine based on attenuated VSV vectors expressing env and gag genes and tested it in rhesus monkeys. Boosting was accomplished using vectors with glycoproteins from different VSV serotypes. Animals were challenged with a pathogenic AIDS virus (SHIV89.6P). Control monkeys showed a severe loss of CD4+ T cells and high viral loads, and 7/8 progressed to AIDS with an average time of 148 days. All seven vaccinees were initially infected with SHIV89.6P but have remained healthy for up to 14 months after challenge with low or undetectable viral loads. Protection from AIDS was highly significant (p = 0.001). VSV vectors are promising candidates for human AIDS vaccine trials because they propagate to high titers and can be delivered without injection.

No abstract