0000000000339552
AUTHOR
Uwe Klemm
Thymus-derived regulatory T cells are positively selected on natural self-antigen through cognate interactions of high functional avidity
Regulatory T (Treg) cells expressing Foxp3 transcripton factor are essential for immune homeostasis. They arise in the thymus as a separate lineage from conventional CD4+Foxp3- T (Tconv) cells. Here, we show that the thymic development of Treg cells depends on the expression of their endogenous cognate self-antigen. The formation of these cells was impaired in mice lacking this self-antigen, while Tconv cell development was not negatively affected. Thymus-derived Treg cells were selected by self-antigens in a specific manner, while autoreactive Tconv cells were produced through degenerate recognition of distinct antigens. These distinct modes of development were associated with the expressi…
Acrosin, the peculiar sperm-specific serine protease.
The sperm enzyme acrosin has long been known as one of the key enzymes in the mammalian fertilization process. Elucidation of primary structures of preproacrosin from various species have allowed a deeper insight into the structural organization and the complex evolution of the sperm proteinase acrosin. In addition to the typical elements of serine proteases, the acrosin molecule possesses one novel domain that might convey DNA-binding properties.