Purging the HIV-1 reservoir through the disruption of the PD-1 pathway

International audiencen.

Unique Aspects of the Design of Phase I/II Clinical Trials of Stem Cell Therapy

This chapter will review the unique aspects and limitations of the design of phase I/II (safety and efficacy) clinical trials of stem cell therapy. Although the classical pharmacologic principles applicable to drugs are not applicable to biologic (live cell) therapeutic agents, an important stage in the development of any new therapeutic agent is the establishment of an optimal dosage and delivery route. This can be particularly challenging when the treatment is a biologic agent, such as stem cells, that may exert its therapeutic effects via complex or poorly understood mechanisms. To date, clinical studies have shown inconsistent findings regarding the relationship between cell dose and clinical outcomes. This can be at least partially attributed to variations in donor cell type, source, characteristics, dosing/concentration, delivery route, underlying mechanisms of action, and efficacy endpoints tested. The current recommendations will be reviewed herein to give new investigators a general understanding of the unique issues that need to be considered and addressed when designing a stem cell therapy phase I/II clinical trial

Microparticle-mediated transfer of the viral receptors CAR and CD46, and the CFTR channel in a CHO cell model confers new functions to target cells

Cell microparticles (MPs) released in the extracellular milieu can embark plasma membrane and intracellular components which are specific of their cellular origin, and transfer them to target cells. The MP-mediated, cell-to-cell transfer of three human membrane glycoproteins of different degrees of complexity was investigated in the present study, using a CHO cell model system. We first tested the delivery of CAR and CD46, two monospanins which act as adenovirus receptors, to target CHO cells. CHO cells lack CAR and CD46, high affinity receptors for human adenovirus serotype 5 (HAdV5), and serotype 35 (HAdV35), respectively. We found that MPs derived from CHO cells (MP-donor cells) constitutively expressing CAR (MP-CAR) or CD46 (MP-CD46) were able to transfer CAR and CD46 to target CHO cells, and conferred selective permissiveness to HAdV5 and HAdV35. In addition, target CHO cells incubated with MP-CD46 acquired the CD46-associated function in complement regulation. We also explored the MP-mediated delivery of a dodecaspanin membrane glycoprotein, the CFTR to target CHO cells. CFTR functions as a chloride channel in human cells and is implicated in the genetic disease cystic fibrosis. Target CHO cells incubated with MPs produced by CHO cells constitutively expressing GFP-tagged CFTR (MP-GFP-CFTR) were found to gain a new cellular function, the chloride channel activity associated to CFTR. Time-course analysis of the appearance of GFP-CFTR in target cells suggested that MPs could achieve the delivery of CFTR to target cells via two mechanisms: the transfer of mature, membrane-inserted CFTR glycoprotein, and the transfer of CFTR-encoding mRNA. These results confirmed that cell-derived MPs represent a new class of promising therapeutic vehicles for the delivery of bioactive macromolecules, proteins or mRNAs, the latter exerting the desired therapeutic effect in target cells via de novo synthesis of their encoded proteins