MHC class II molecules enhance Toll-like receptor mediated innate immune responses.

Background: Major histocompatibility complex (MHC) class II molecules play crucial roles in immune activation by presenting foreign peptides to antigen-specific T helper cells and thereby inducing adaptive immune responses. Although adaptive immunity is a highly effective defense system, it takes several days to become fully operational and needs to be triggered by danger-signals generated during the preceding innate immune response. Here we show that MHC class II molecules synergize with Toll-like receptor (TLR) 2 and TLR4 in inducing an innate immune response.

Gene therapy of hematopoietic stem cells: strategies for improvement.

Gene therapy of hematopoietic stem cells (HSC) is limited by low frequency of the target cells, their quiescent nature, poor engraftment of treated HSC, and lack of a selective growth advantage of genetically modified cells. Lentiviral vectors combined with positive selection strategies using conditional cell-growth switches should allow for improvement.