Qualitative differences in the innate and adaptive responses elicited by different HIV vaccine candidates have not been thoroughly investigated. We tested the ability of the Aventis Pasteur live recombinant canarypox vector (ALVAC)–SIV, DNA–SIV and Ad26–SIV vaccine prime modalities together with two ALVAC–SIV + gp120 protein boosts to reduce the risk of SIVmac251 acquisition in rhesus macaques. We found that the DNA and ALVAC prime regimens were effective, but the Ad26 prime was not. The activation of hypoxia and the inflammasome in CD14+CD16− monocytes, gut-homing CCR5-negative CD4+ T helper 2 (TH2) cells and antibodies to variable region 2 correlated with a decreased risk of SIVmac251 acquisition. By contrast, signal transducer and activator of transcription 3 activation in CD16+ monocytes was associated with an increased risk of virus acquisition. The Ad26 prime regimen induced the accumulation of CX3CR1+CD163+ macrophages in lymph nodes and of long-lasting CD4+ TH17 cells in the gut and lungs. Our data indicate that the selective engagement of monocyte subsets following a vaccine prime influences long-term immunity, uncovering an unexpected association of CD14+ innate monocytes with a reduced risk of SIVmac251 acquisition.

Acute myeloid leukemia (AML) is a bone marrow derived blood cancer where intercellular communication in the leukemic bone marrow participates in disease development, progression and chemoresistance. Tunneling nanotubes (TNTs) are intercellular communication structures involved in transport of cellular contents and pathogens, also demonstrated to play a role in both cell death modulation and chemoresistance. Here we investigated the presence of TNTs by live fluorescent microscopy and identified TNT formation between primary AML cells and in AML cell lines. We found that NF-κB activity was involved in TNT regulation and formation. Cytarabine downregulated TNTs and inhibited NF-κB alone and in combination with daunorubicin, providing additional support for involvement of the NF-κB pathway in TNT formation. Interestingly, daunorubicin was found to localize to lysosomes in TNTs connecting AML cells indicating a novel function of TNTs as drug transporting devices. We conclude that TNT communication could reflect important biological features of AML that may be explored in future therapy development.

A pproximately 2 to 3% of human T cell leukemia virus type 1 (HTLV-1)-infected individuals develop adult T-cell leukemia/lymphoma (ATL) and another 2 to 3% develop HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) in their lifetimes (1-4). In addition to HAM/TSP (5, 6), HTLV-1 is also associated with other inflammatory conditions, such as uveitis (6) Sjögren's syndrome (7), bronchoalveolitis and arthritis (8), and polymyositis (9). It is noteworthy that some patients present with more than one of these inflammatory conditions (10). HTLV-1 primarily infects CD4 ϩ and CD8 ϩ effector and memory T cells and regulatory CD4 ϩ CD25 ϩ T cells (11,12). A high viral DNA burden in peripheral blood mononuclear cells (PBMCs) is a risk factor for HAM/TSP (13) and ATL development (14-16), and patients with HAM/TSP have a higher virus level in the cerebrospinal fluid (CSF) than in the peripheral blood (12). The virus level alone is not sufficient to differentiate symptomatic patients from healthy carriers, suggesting the importance of other factors, including the host immune response (16)(17)(18)(19)(20). HAM/TSP patients present diverse immunological alterations, such as increased levels of spontaneous lymphocyte proliferation (21, 22), tax-specific cytotoxic CD8 ϩ T cell expansion, and the production of high levels of inflammatory cytokines (23)(24)(25). Several studies have also suggested that monocytes are involved in immune reg-