Development of a new mouse/human FoxP3 antibody using rabbit recombinant antibody technology (IRC4P.477)

Tregs play a key role in immune system suppression during autoimmunity and tumor development. Tregs are classified as CD4+CD25+FoxP3+, and exist as either nTregs originating from the thymus, or iTregs derived from CD4+ effector T cells in the periphery. Reduction in Treg numbers leads to autoimmunity; this is clearly shown in scurfy mice where FoxP3 has been deleted, Treg numbers are severely reduced, and mice succumb to autoimmunity early in life. In contrast, Tregs play a debilitating role in cancer biology when the Treg numbers are elevated, and the immune response is dampened allowing cancer cells to evade the immune system. Thus, the correct balance of Tregs is essential for maintaining immune homeostasis. FoxP3 has been widely used as a marker of Tregs, and many antibodies are available on the market that distinguish the Treg population in human or mouse cells. We developed a novel FoxP3 antibody and Fix and Perm buffer system that is comparable to current clones, but recognizes both mouse and human FoxP3 equally well, eliminating the need for separate antibodies. The ms/hu FoxP3 antibody was generated using our Rabbit Recombinant antibody technology, which allows for selecting high specificity, high affinity antibodies, lot to lot consistency and detection of both mouse and human nTregs and iTregs. This allows researchers to extend their mouse models into clinical studies without a change in the antibody clone eliminating a variable and streamlining the process.

A new subset of CD57+NKG2Chi NK cells is observed after HCMV infection infection (108.4)

During human cytomegalovirus (HCMV) infection, there is a preferential expansion of Natural Killer (NK) cells expressing the activating CD94-NKG2C receptor complex, implicating this receptor in the recognition of HCMV-infected cells. We recently showed that CD57+ NK cells within the CD56dimCD16+ NK cell compartment are highly mature. We hypothesized that human NK cells previously expanded in response to viruses or other pathogens will be marked by expression of CD57. Indeed, we observed in HCMV+ donors that NK cells expressing the activating NKG2C receptor are preferentially CD57+. These CD57+NKG2Chi NK cells have down-regulated the inhibitory NKG2A receptor and some inhibitory KIRs. These CD57+NKG2Chi NK cells respond better to activation through the NKG2C receptor. Furthermore, CD57+NKG2Chi NK cells expressed high amounts of LIR-1, another receptor that recognizes HCMV. Finally, in solid organ transplant recipients with symptomatic HCMV infection the percentage of CD57+NKG2Chi NK cells among the total NK cell population increased as the HCMV plasma viral load decreased. In these patients the NKG2C+ NK cells expanded and proliferated before becoming NKG2Chi and acquiring CD57 expression. Together, these results suggest that during HCMV infection, NKG2C+ NK cells expand to fight the infection, and after several divisions acquire CD57. In humans CD57 might provide a marker of "memory" or "terminally differentiated" NK cells that have been expanded in response to infection.