Positive selection by thymic nurse cells requires IL-1 beta and is associated with an increased Bcl-2 expression.
Pezzano M, Philp D, Stephenson S, Li Y, Reid V, Maitta R, Guyden JC. Positive selection by thymic nurse cells requires IL-1 beta and is associated with an increased Bcl-2 expression. Cell Immunol. 1996 May 01; 169(2):174-84.