Murine Embryonic Stem Cell Plasticity Is Regulated through Klf5 and Maintained by Metalloproteinase MMP1 and Hypoxia.

Mouse embryonic stem cells (mESCs) are expanded and maintained pluripotent in vitro in the presence of leukemia inhibitory factor (LIF), an IL6 cytokine family member which displays pleiotropic functions, depending on both cell maturity and cell type. LIF withdrawal leads to heterogeneous differentiation of mESCs with a proportion of the differentiated cells apoptosising. During LIF withdrawal, cells sequentially enter a reversible and irreversible phase of differentiation during which LIF addition induces different effects.

Development of an in vitro potency test for tetanus vaccines: an immunoassay based on Hc fragment determination.

In the three Rs rule context, we have developed a method to quantify tetanus toxoid by ELISA detection of the specific Hc fragment. This fragment and several anti Hc fragment antibodies have been described as protective in mice models. By developing this assay, we have detected Hc presence in tetanus toxoid.