Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) poses a public health threat for which preventive and therapeutic agents are urgently needed. Neutralizing antibodies are a key class of therapeutics which may bridge widespread vaccination campaigns and offer a treatment solution in populations less responsive to vaccination. Herein, we report that high-throughput microfluidic screening of antigen-specific B-cells led to the identification of LY-CoV555 (also known as bamlanivimab), a potent anti-spike neutralizing antibody from a hospitalized, convalescent patient with coronavirus disease 2019 (COVID-19). Biochemical, structural, and functional characterization of LY-CoV555 revealed high-affinity binding to the receptor-binding domain, angiotensin converting enzyme 2 binding inhibition, and potent neutralizing activity. A pharmacokinetic study of LY-CoV555 conducted in cynomolgus monkeys demonstrated a mean half-life of 13 days, and clearance of 0.22 mL/hr/kg, consistent with a typical human therapeutic antibody. In a rhesus macaque challenge model, prophylactic doses as low as 2.5 mg/kg reduced viral replication in the upper and lower respiratory tract in samples collected through study Day 6 following viral inoculation. This antibody has entered clinical testing and is being evaluated across a spectrum of COVID-19 indications, including prevention and treatment.

SARS-CoV-2 poses a public health threat for which therapeutic agents are urgently needed. Herein, we report that high-throughput microfluidic screening of antigen-specific B-cells led to the identification of LY-CoV555, a potent anti-spike neutralizing antibody from a convalescent COVID-19 patient. Biochemical, structural, and functional characterization revealed high-affinity binding to the receptor-binding domain, ACE2 binding inhibition, and potent neutralizing activity. In a rhesus macaque challenge model, prophylaxis doses as low as 2.5 mg/kg reduced viral replication in the upper and lower respiratory tract. These data demonstrate that high-throughput screening can lead to the identification of a potent antiviral antibody that protects against SARS-CoV-2 infection.

The human immunodeficiency virus encodes the transcriptional transactivator Tat, which binds to the transactivation response (TAR) RNA stem-loop in the viral long terminal repeat (LTR) and increases rates of elongation rather than initiation of transcription by RNA polymerase II (Pol II). In this study, we demonstrate that Tat binds directly to the cyclin-dependent kinase 7 (CDK7), which leads to productive interactions between Tat and the CDK-activating kinase (CAK) complex and between Tat and TFIIH. Tat activates the phosphorylation of the carboxy-terminal domain (CTD) of Pol II by CAK in vitro. The ability of CAK to phosphorylate the CTD can be inhibited specifically by a CDK7 pseudosubstrate peptide that also inhibits transcriptional activation by Tat in vitro and in vivo. We conclude that the phosphorylation of the CTD by CAK is essential for Tat transactivation. Our data identify a cellular protein that interacts with the activation domain of Tat, demonstrate that this interaction is critical for the function of Tat, and provide a mechanism by which Tat increases the processivity of Pol II.

The human immunodeficiency virus (HIV) encodes a transcriptional transactivator (Tat), which binds to an RNA hairpin called the transactivation response element (TAR) that is located downstream of the site of initiation of viral transcription. Tat stimulates the production of full-length viral transcripts by RNA polymerase II (pol II). In this study, we demonstrate that Tat coimmunoprecipitates with the pol II holoenzyme in cells and that it binds to the purified holoenzyme in vitro. Furthermore, Tat affinity chromatography purifies a holoenzyme from HeLa nuclear extracts which, upon addition of TBP and TFIIB, supports Tat transactivation in vitro, indicating that it contains all the cellular proteins required for the function of Tat. By demonstrating that Tat interacts with the holoenzyme in the absence of TAR, our data suggest a single-step assembly of Tat and the transcription complex on the long terminal repeat of HIV.

Rheumatoid arthritis is a multifactorial disease characterized by chronic inflammation of the joints. Both genetic and environmental factors are involved in the pathogenesis leading to joint destruction and ultimately disability. In the inflamed RA joint the synovium is highly infiltrated by CD4+ T cells, B cells and macrophages, and the intimal lining becomes hyperplastic owing to the increased number of macrophage‐like and fibroblast‐like synoviocytes. This hyperplastic intimal synovial lining forms an aggressive front, called pannus, which invades cartilage and bone structures, leading to the destruction and compromised function of affected joints. This process is mediated by a number of cytokines (tumor necrosis factor‐α, interleukin‐1, interleukin‐6, interleukin‐17 interferon‐γ, etc.), chemokines (monocyte chemoattractant protein‐1, monocyte chemoattractant protein‐4 CCL18, etc.), cell adhesion molecules (intercellular adhesion molecule‐1, vascular cell adhesion molecule‐1, etc.) and matrix metalloproteinases. Expression of these molecules is controlled at the transcription level and activation of a limited number of transcription factors is involved in this process.