Two articles in this month's issue touch on aspects of vaccine development. On page 630, Olivera Finn outlines the challenges for cancer-vaccine development. Some of these challenges are common to all vaccines, whether the goal is fighting infection or cancer. But cancer vaccines also have unique challenges, as Finn explains. Developing a vaccine for Ebola virus has only recently become a high priority. On page 677, Heinz Feldmann and colleagues describe the discovery of Ebola virus and the drive to develop a vaccine against this highly pathogenic organism. Vaccine development is also covered in our Highlights section this month (see 'Shoot but don't kill' on page 605) — a recent study showing that DNA vaccines delivered to the skin that encode anti-apoptotic molecules, as well as antigen, enhance vaccine immunogenicity.

Three articles in this issue feature the role of cytokines in the immune system. Jennifer Gommerman and Jeffrey Browning review the role of lymphotoxin/LIGHT in lymphoid microenvironments (page 642). Jean-Christophe Renauld (page 667) outlines the diverse roles of class II cytokines and their receptors in modulating inflammation and responses to viral infection. And on page 609, Michael Croft argues that several members of the TNFR superfamily, in addition to the CD28–B7 superfamily, can provide co-stimulatory signals to T cells.

Elsewhere in this issue, David Roth discusses the mechanisms that protect the genome from oncogenic translocations during V(D)J recombination. And finally, whereas the common view is that proteolytic processing yields peptides that can bind to MHC class II molecules (a 'cut first, bind later' model), Eli Sercarz and Emanual Maverakis summarize the evidence for an alternative, 'bind first, trim later' model.