Primed antigen-specific CD4+ T cells are required for NK cell activation in vivo upon Leishmania major infection.

The ability of NK cells to rapidly produce IFN-gamma is an important innate mechanism of resistance to many pathogens including Leishmania major. Molecular and cellular components involved in NK cell activation in vivo are still poorly defined, although a central role for dendritic cells has been described. In this study, we demonstrate that Ag-specific CD4(+) T cells are required to initiate NK cell activation early on in draining lymph nodes of L.

[Compensating presbyopia: a new physiological progressive lens (author's transl)].

After discussing the functional disadvantages arising after correction of presbyopia with uni--or multifocal lenses, the authors describe the optical and physiological advantages of a lens with progressively increasing power. The principal qualities of these physiologically progressive lenses are studies, and the results of a preliminary survey concerning their use are analysed. The indications for, and adaptation and tolerance of these lenses are outlined.