Transgender women (TW) are at increased risk for both human immunodeficiency virus (HIV) and cardiovascular disease (CVD). Antiretroviral therapy-treated HIV has been associated with a two-fold increased risk of CVD, potentially due to dysregulated Toll-like receptor (TLR)-induced immune activation. Use of estrogens in feminizing hormone therapy (FHT) may enhance inflammatory responses and the risk of cardiovascular mortality in TW. Despite this, the immunomodulatory effects of estrogen use in TW with HIV have been inadequately explored.
As an in vitro model for FHT, cryopreserved PBMCs (cryoPBMCs) from HIV negative (HIV-), HIV+ ART-suppressed (HIV+SP), and HIV+ ART-unsuppressed (HIV+USP) cisgender men were cultured overnight in the presence of 17-β estradiol or 17-α ethinylestradiol with and without the TLR4 agonist LPS or the TLR8 agonist ssPolyU. Monocyte activation (CD69, HLA-DR, CD38) was assessed by flow cytometry. Cytokine levels (IL-6, TNF-α, IL-1β, and IL-10) were measured in cell culture supernatants by Legendplex. Levels of phosphorylated TLR signaling molecules (JNK, MAPK p38) were assessed by Phosflow. Plasma levels of immune activation biomarkers (LPS-binding protein, monocyte activation markers sCD14 and sCD163, and inflammatory molecules IL-6 and TNF-α receptor I) were measured by ELISA.
PBMCs from people with HIV (PWH) produced greater levels of inflammatory cytokines following exposure to LPS or ssPolyU compared to levels from cells of HIV- individuals. While estrogen exposure alone induced mild changes in immune activation, LPS-induced TLR4 activation was elevated with estrogen in cisgender men (CM) with HIV, increasing monocyte activation and inflammatory cytokine production (IL-6, TNF-α). Interestingly, testosterone inhibited LPS-induced cytokine production in CM regardless of HIV status. Plasma markers of immune activation and microbial translocation (e.g., sCD14, sCD163, LPS-binding protein) were generally higher in PWH compared to HIV- CM, and these markers were positively associated with in vitro responsiveness to estrogen and LPS in CM with HIV.
Our in vitro data suggest that estrogen exposure may enhance innate immune activation in PWH. Further examination is needed to fully understand the complex interactions of FHT, HIV, and CVD in TW, and determine optimal FHT regimens or supplementary treatments aimed at reducing excess immune activation.
Copyright © 2022 Kettelhut, Bowman, Gabriel, Hand, Liyanage, Kulkarni, Avila-Soto, Lake and Funderburg.

This study aimed to investigate the possible relationship between the two biomarkers presepsin and procalcitonin (PCT) and monocyte immune function, and to explore their combination in mortality prediction in the early stage of sepsis. A total of 198 patients with bacterial infection and diagnosed with sepsis and 40 healthy control subjects were included. Blood samples were collected on admission within 24 h. Plasma concentrations of presepsin and PCT were measured. Expression of monocyte surface CD14, programmed cell death receptor ligand-1 (PD-L1) and human leucocyte Ag (HLA)-DR were determined using flow cytometry. Levels of plasma presepsin and PCT were significantly higher under septic conditions, and increased with the progression of sepsis. Monocyte CD14 and HLA-DR expression were decreased, while PD-L1 was overexpressed in sepsis compared to control. Presepsin and PCT concentrations were positively correlated with Sequential Organ Failure Assessment score, Acute Physiology and Chronic Health Evaluation System II score and PD-L1, while they were negatively correlated with CD14 and HLA-DR. Presepsin plus monocyte HLA-DR mean fluorescence intensity had the highest prognostic value over other parameters alone or in combination. Presepsin and PCT had a weak correlation with monocyte dysfunction during early sepsis. The combination of presepsin and monocyte HLA-DR could help improve prognostic value.

Receptor occupancy (RO) assays measure drug target engagement, and are used as pharmacodynamic (PD) biomarkers. RO assays are commonly performed by flow cytometry and often require multiplexing for assessment of multiple PD biomarkers when specimen volumes are limited. We present multiplexed RO assays for an IGF1R-EGFR bispecific antibody (Bs-Ab) and a CTLA4-Ig recombinant fusion protein to demonstrate key considerations for accurate RO assessment.
RO in cynomolgus monkeys was determined in whole blood using flow cytometry. Free and total receptors were measured using anti-receptor fluorescence-labeled detection reagents, competitive and noncompetitive to drug, respectively.
RO of IGF1R was examined as PD for Bs-Ab, since IGF1R was expressed on blood cells. Multiplexed measurements of free and total IGF1R showed that IGF1R expression measured by total receptor was highly variable, impacting interpretation of free-IGF1R. Normalization of free-over-total IGF1R measurements compensated for variability of receptor expression allowing for accurate RO assessment. RO of CTLA4-Ig, a recombinant fusion protein targeting CD80 and CD86 receptors, was multiplexed to simultaneously measure target engagements for both receptors. Both RO methods demonstrated specificity of receptor measurements without cross-reactivity to each other in multiplexed formats. RO methods were used for evaluation of PD activity of Bs-Ab and CTLA4-Ig in cynomolgus monkeys. In both cases, RO results showed dose-dependent target engagement, corresponding well to the pharmacokinetics.
Multiplexed RO methods allowed accurate assessment of PD activity for Bs-Ab and CTLA4-Ig, facilitating development of these biopharmaceuticals from preclinical to clinical stages.
© 2015 International Clinical Cytometry Society.

The ectoenzyme CD73 catalyzes the hydrolysis of AMP, and is one of the most important producers of extracellular adenosine. On regulatory T cells, CD73 is necessary for immunosuppressive functions, and on Th17 cells CD73-generated adenosine exerts anti-inflammatory effects. However, the expression and function of CD73 in pro-inflammatory M1 and in immunosuppressive M2 macrophages is largely unknown. Here we show that CD73 expression and enzyme activity were induced in in vitro polarized pro-inflammatory human M(LPS+TNF) monocytes/macrophages, while CD73 was absent from immunosuppressive M(IL-4+M-CSF)-polarized macrophages. Inhibition of CD73 activity with the inhibitor AMPCP did not affect the polarization of human monocytes. In mice, CD73 was present on resident peritoneal macrophages. In striking contrast, elicited peritoneal macrophages remained CD73 negative regardless of their polarization towards either a pro-inflammatory M(LPS) or anti-inflammatory M(IL-4c) direction. Finally, the ability of peritoneal macrophages to polarize to pro- and anti-inflammatory cells was perfectly normal in CD73-deficient mice in vivo. These data indicate that, in contrast to other major leukocyte subpopulations, CD73 activity on macrophages does not play a major role in their polarization and that in mice host CD73 on any cell type is not required in vivo for peritoneal macrophage polarization towards either a pro- or an anti-inflammatory direction.

Angiogenesis is a critical factor in the growth and dissemination of solid tumors. Indeed, tumor vasculature is abnormal and contributes to the development and spread of malignancies by creating a hostile microenvironment. The alternative SDF-1/CXCL12 receptor, CXCR7, is frequently and specifically expressed in tumor-associated vessels. In this study, we examine the role of endothelium-expressed CXCR7 in tumor vascular dysfunction by specifically examining the contribution of CXCR7 to endothelial cell (EC) proliferation. We demonstrate that CXCR7 expression is sufficient to drive post-confluent growth in EC cultures. Further, we provide a novel mechanism for CXCR7-mediated proliferation via proteasomal degradation of the tumor suppressor protein Rb. These findings identify a heretofore unappreciated role for CXCR7 in vascular dysfunction and confirm this receptor as a plausible target for anti-tumor therapy.