Receptor transfer between immune cells by autoantibody-enhanced, CD32-driven trogocytosis is hijacked by HIV-1 to infect resting CD4 T cells.

Immune cell phenotyping frequently detects lineage-unrelated receptors. Here, we report that surface receptors can be transferred from primary macrophages to CD4 T cells and identify the Fcγ receptor CD32 as driver and cargo of this trogocytotic transfer. Filamentous CD32 nanoprotrusions deposit distinct plasma membrane patches onto target T cells.

Activation-neutral gene editing of tonsillar CD4 T cells for functional studies in human ex vivo tonsil cultures.

The molecular and immunological properties of tissue-resident resting CD4 T cells are understudied due to the lack of suitable gene editing methods. Here, we describe the ex vivo culture and gene editing methodology ediTONSIL for CD4 T cells from human tonsils. Optimized CRISPR-Cas9 RNP nucleofection results in knockout efficacies of over 90% without requiring exogenous activation.

Rapid, efficient and activation-neutral gene editing of polyclonal primary human resting CD4 T cells allows complex functional analyses.

CD4 T cells are central mediators of adaptive and innate immune responses and constitute a major reservoir for human immunodeficiency virus (HIV) in vivo. Detailed investigations of resting human CD4 T cells have been precluded by the absence of efficient approaches for genetic manipulation limiting our understanding of HIV replication and restricting efforts to find a cure. Here we report a method for rapid, efficient, activation-neutral gene editing of resting, polyclonal human CD4 T cells using optimized cell cultivation and nucleofection conditions of Cas9-guide RNA ribonucleoprotein complexes.

Evidence for increased SARS-CoV-2 susceptibility and COVID-19 severity related to pre-existing immunity to seasonal coronaviruses.

The importance of pre-existing immune responses to seasonal endemic coronaviruses (HCoVs) for the susceptibility to SARS-CoV-2 infection and the course of COVID-19 is the subject of an ongoing scientific debate. Recent studies postulate that immune responses to previous HCoV infections can either have a slightly protective or no effect on SARS-CoV-2 pathogenesis and, consequently, be neglected for COVID-19 risk stratification. Challenging this notion, we provide evidence that pre-existing, anti-nucleocapsid antibodies against endemic α-coronaviruses and S2 domain-specific anti-spike antibodies against β-coronavirus HCoV-OC43 are elevated in patients with COVID-19 compared to pre-pandemic donors.

Dynamics of urinary and respiratory shedding of Severe acute respiratory syndrome virus 2 (SARS-CoV-2) RNA excludes urine as a relevant source of viral transmission.

Purpose: To investigate the expression of the receptor protein ACE-2 alongside the urinary tract, urinary shedding and urinary stability of SARS-CoV-2 RNA.

Methods: Immunohistochemical staining was performed on tissue from urological surgery of 10 patients. Further, patients treated for coronavirus disease (COVID-19) at specialized care-units of a university hospital were assessed for detection of SARS-CoV-2 RNA in urinary samples via PCR, disease severity (WHO score), inflammatory response of patients.

Contribution of Heptose Metabolites and the Pathogenicity Island to the Activation of Monocytes/Macrophages by .

The human gastric pathogen activates human epithelial cells by a particular combination of mechanisms, including NOD1 and ALPK1-TIFA activation. These mechanisms are characterized by a strong participation of the bacterial pathogenicity island, which forms a type IV secretion system (CagT4SS) that enables the bacteria to transport proteins and diverse bacterial metabolites, including DNA, glycans, and cell wall components, into human host cells. Building on previous findings, we sought to determine the contribution of lipopolysaccharide inner core heptose metabolites (ADP-heptose) in the activation of human phagocytic cells by .