News & Comment

In this Essay, Gérard Eberl presents a model of immunity that is based on an equilibrium between four types of immune response. Alteration of the internal or microbial environment leads to immune disequilibrium and determines immune protection or pathology.

This Essay considers how prokaryotic and mammalian immune systems ensure tolerance or resistance to genetic elements. In particular, the authors discuss the restriction–modification and CRISPR–Cas activities of prokaryotes and the analogous immune pathways found in mammals.

Here, the authors present a new theoretical framework — the discontinuity theory — to account for how the immune system generates an appropriate immune response to any perceived disturbance. On the the basis of this theory, the authors present a mathematical model and provide examples to explain how this model can account for diverse immune responses.

Can the immune system influence how our brain works? Here, Jonathan Kipnis and colleagues discuss the emerging hypothesis that T cells, and in particular their production of interleukin–4, can have beneficial effects on learning and memory.

In this Essay, the authors present a new perspective on how immune responses are regulated. They propose that the class of immune response is tailored to suit the tissue in which it is occurring rather than the invading pathogen.

Stefan Kaufmann looks to the future of vaccination against tuberculosis. By drawing on past and present vaccination approaches, he proposes that the most successful strategy for preventing tuberculosis in the future will combine different vaccine candidates and use a prime–boost approach.

In this article, the ways in which dendritic-cell nomenclature has evolved are discussed, focusing on the new trend to specifically define a dendritic cell not only by its phenotypic maturation state but also by its function.