Studying Stem Cell Biology in Intact and Whole-Body Regenerating Hydra by Flow Cytometry

The freshwater Hydra polyp is a versatile model to study whole-body regeneration from a developmental as well as a cellular point of view. The outstanding regenerative capacities of Hydra are based on its three populations of adult stem cells located in the central body column of the animal. There, these three populations, gastrodermal epithelial, epidermal epithelial, and interstitial, continuously cycle in homeostatic conditions, and their activity is locally regulated after mid-gastric bisection. Moreover, they present an unusual cycling behavior with a short G1 phase and a pausing in G2. This particular cell cycle has been studied for a long time with classical microscopic methods. We describe here two flow cytometry methods that provide accurate and reproducible quantitative data to monitor cell cycle regulation in homeostatic and regenerative contexts. We also present a cell sorting procedure based on flow cytometry, whereby stem cells expressing a fluorescent reporter protein in transgenic lines can be enriched for use in applications such as transcriptomic, proteomic, or cell cycle analysis

Enhanced pulmonary immunopathology following neonatal priming with formalin-inactivated respiratory syncytial virus but not with the BBG2NA vaccine candidate

Prevention of respiratory syncytial virus (RSV) disease will implicate neonatal priming. However, neonatal antigen exposure frequently results into Th2-like responses, some of which are critical for formalin-inactivated RSV (FI-RSV)-associated lung immunopathology. Neonatal immunization of mice may thus represent a more stringent model of RSV-enhanced pathology than adults. Indeed, after RSV challenge, lung cell infiltration, lymphocyte activation, and eosinophilia were higher following neonatal compared with adult FI-RSV priming of BALB/c mice. Unexpectedly, similar findings were obtained with Al(OH)(3)-adsorbed live RSV. In contrast, neonatal priming with BBG2Na, a recombinant RSV subunit vaccine candidate, formulated in either Al(OH)(3) or TiterMax (a Th1-driving adjuvant) resulted in predominant Th2- or Th1-like responses, respectively, but never elicited lung immunopathology post-challenge. Importantly, our data emphasize that the induction of Th2-like responses by RSV subunit vaccines do not necessarily imply lung immunopathology

The AJ521 antibody detects the human CD1b protein by flow cytometry

The AJ521 antibody detects the human CD1b protein by flow cytometry

The AJ516 antibody does not detect the human CD1a protein by flow cytometry

The AJ516 antibody does not detect the human CD1a protein by flow cytometry

The AJ519 antibody detects the human TAC/ILR2A protein by flow cytometry

The AJ519 antibody detects the human TAC protein by flow cytometry

The AJ517 antibody detects the mouse CD8β protein by flow cytometry

The AJ517 antibody detects the mouse CD8β protein by flow cytometry

IDO-orchestrated crosstalk between pDCs and Tregs inhibits autoimmunity

Plasmacytoid dendritic cells (pDCs) have been shown to both mediate and prevent autoimmunity, and the regulation of their immunogenic versus tolerogenic functions remains incompletely understood. Here we demonstrate that, compared to other cells, pDCs are the major expressors of Indoleamine-2,3-dioxygenase (IDO) in steady-state lymph nodes (LNs). IDO expression by LN pDCs was closely dependent on MHCII-mediated, antigen-dependent, interactions with Treg. We further established that IDO production by pDCs was necessary to confer suppressive function to Tregs. During EAE development, IDO expression by pDCs was required for the generation of Tregs capable of dampening the priming of encephalitogenic T cell and disease severity. Thus, we describe a novel crosstalk between pDCs and Tregs: Tregs shape tolerogenic functions of pDCs prior to inflammation, such that pDCs in turn, promote Treg suppressive functions during autoimmunity

AQ806, AS739, AT693, AU197 and AU734 antibodies recognize the spike S protein from SARS-CoV-2 by flow cytometry

The recombinant antibodies AQ806, AS739, AT693, AU197 and AU734 detect by flow cytometry the spike S protein from SARS-CoV-2

AD822, AW199, AW200 and AW201 antibodies against the human Fas receptor (CD95) bind the surface of HEK293 cells as revealed by flow cytometry

The recombinant antibodies AD822, AW199, AW200 and AW201 bind HEK293 cells expressing the human Fas receptor protein as assessed by flow cytometry.</p