An In Vitro Model of Blood-Brain Barrier for Studies on HIV Neuroinflammation and CNS Antibody Penetration.

The blood-brain barrier (BBB) is one of several barriers between the brain and the peripheral blood system to maintain homeostasis. Understanding the interactions between infectious agents such as human immunodeficiency virus type 1 (HIV-1), which are capable of traversing the BBB and causing neuroinflammation requires modeling an authentic BBB in vitro. Such an in vitro BBB model also helps develop means of targeting viruses that reside in the brain via natural immune effectors such as antibodies. The BBB consists of human brain microvascular endothelial cells (HBMECs), astrocytes, and pericytes. Here we report in vitro methods to establish a dual-cell BBB model consisting of primary HBMECs and primary astrocytes to measure the integrity of the BBB and antibody penetration of the BBB, as well as a method to establish a single cell BBB model to study the impact of HIV-1 infected medium on the integrity of such a BBB.

Tracking fluorescently labeled IL-15 and anti-PD-1 in the tumor microenvironment and draining lymph nodes.

Understanding the dynamics of the tumor microenvironment (TME) has become vital in discovering new targets for effective immunotherapies and enhancing current treatments. However, localization and distribution of immune cells and treatment biomolecules are poorly characterized to date. In this study, a murine Luminal B mammary adenocarcinoma model received a combinatorial treatment of fluorescently labeled anti-PD-1-Cy3 and IL-15 complex-Cy5 injected interperitoneally and intratumorally, respectively. Fluorescent labeling allowed for the visualization of the distribution of IL-15 complexes and anti-PD-1, as well as their localization to immune cells in the TME and tumor-draining lymph node. Using fluorescent microscopy and light sheet microscopy of whole-clarified tumors and draining lymph nodes, the localization of IL-15 complexes was found to be distributed around the periphery of the tumor at 4 h post injection and medially located at the center of the tumor at 24 h post injection, corresponding with high densities of CD8 cells in the tumor present at 48 h and 72 h post injection. Anti-PD-1 was distributed around the perimeter of the tumor and colocalized to IL-15 in the draining lymph nodes 24 h post injection. Colocalization of IL-15 was also established with NK cells, CD8+ T cells, and macrophages. This study develops a novel method to spatiotemporally track fluorescently labeled immunotherapeutic biomolecules in vivo, with implications for optimizing and further understanding the pharmacokinetics of clinical immunotherapies.

Bulk IgG glycosylation predicts COVID-19 severity and vaccine antibody response.

Although vaccination efforts have expanded, there are still gaps in our understanding surrounding the immune response to SARS-CoV-2. Measuring IgG Fc glycosylation provides insight into an infected individual's inflammatory state, among other functions. We set out to interrogate bulk IgG glycosylation changes from SARS-CoV-2 infection and vaccination, using plasma from mild or hospitalized COVID-19 patients, and from vaccinated individuals. Inflammatory glycans are elevated in hospitalized COVID-19 patients and increase over time, while mild patients have anti-inflammatory glycans that increase over time, including increased sialic acid correlating with RBD antibody levels. Vaccinated individuals with low RBD antibody levels and low neutralization have the same IgG glycan traits as hospitalized COVID-19 patients. In addition, a small vaccinated cohort reveals a decrease in inflammatory glycans associated with peak IgG concentrations and neutralization. This report characterizes the bulk IgG glycome associated with COVID-19 severity and vaccine responsiveness and can help guide future studies into SARS-CoV-2 protective immunity.