●Oceans of bacteria Stephen Giovannoni Nature 29 July (2004) The debate on what constitutes a bacterial species rumbles on. In this News and Views article, Stephen Giovannoni comments on work by Acinas and colleagues in which they analysed microbial diversity using 16S rRNA clone libraries from a marine bacterioplankton community and identified microdiverse clusters — populations of cells they suggest can be regarded as species or species 'ecotypes'.

●Mutual attraction: does it benefit the host or the bug? JoAnne L. Flynn Nature Immunology August (2004) JoAnne Flynn discusses the implication of the work by Cosma et al. in which a Mycobacterium marinum model was used to analyse the dynamic nature of mycobacterial granulomas.

●Antiprion immunotherapy: to suppress or to stimulate? Adriano Aguzzi & Christina J. Sigurdson Nature Reviews Immunology September (2004) Although human prion diseases are rare, they are invariably fatal, and treatments for them remain elusive. Aguzzi and Sigurdson review the pathophysiology of prion diseases in mouse models, and discuss their relevance to immunotherapeutic and immunoprophylactic antiprion strategies.

●Working with dangerous bugs Helen Quill & Maria Giovanni Nature Immunology August (2004)

●Oncogenic mechanisms of Helicobacter pylori CagA protein Masanori Hatakeyama Nature Reviews Cancer September (2004)

●Staphylococcal protein A inflames the lungs Birgitta Henriques Normark, Staffan Normark & Anna Norrby-Teglund Nature Medicine August (2004)

●Urgently needed: a filter for the HIV-1 vaccine pipeline John P. Moore & Dennis R. Burton Nature Medicine August (2004)

●Paradise lost & paradigm found Robert I. Lehrer Nature Immunology August (2004)

●Out of Thailand, into Africa Julie Clayton Nature 08 July (2004) As part of a series of News Features written to coincide with the XVth International AIDS Conference in Bangkok, Julie Clayton of Nature talks to Krisana Kraisintu, the former director of the Research and Development Institute of Thailand's Government Pharmaceutical Organization (GPO), who is now leading the drive to get generic versions of branded anti-HIV drugs into sub-saharan Africa.

●Correlates of immune protection in HIV-1 infection: what we know, what we don't know, what we should know Giuseppe Pantaleo & Richard A. Koup Nature Medicine August (2004) Defining the immune correlates of protection during vaccination and natural infection has become a key step in vaccine development. In this excellent Perspective, Pantaleo and Koup emphasize the importance of determining the correlates of protection for individual HIV vaccines during Phase III clinical trials.