Journal of Experimental Medicine Commentaries

Crippling HIV one mutation at a time

Allen, T. M., Altfeld, M. — 2008-05-12

Accumulating data suggest that not all human immunodeficiency virus (HIV)-1–specific immune responses are equally effective at controlling HIV-1 replication. A new study now demonstrates that multiple immune-driven sequence polymorphisms in the highly conserved HIV-1 Gag region of transmitted viruses are associated with reduced viral replication in newly infected humans. These data suggest that targeting these and other conserved viral regions may be the key to developing an effective HIV-1 vaccine.

The role of CTCF in regulating nuclear organization

Williams, A., Flavell, R. A. — 2008-04-14

The spatial organization of the genome is thought to play an important part in the coordination of gene regulation. New techniques have been used to identify specific long-range interactions between distal DNA sequences, revealing an ever-increasing complexity to nuclear organization. CCCTC-binding factor (CTCF) is a versatile zinc finger protein with diverse regulatory functions. New data now help define how CTCF mediates both long-range intrachromosomal and interchromosomal interactions, and highlight CTCF as an important factor in determining the three-dimensional structure of the genome.

Fixing DNA breaks during class switch recombination

Jolly, C. J., Cook, A. J.L., Manis, J. P. — 2008-03-17

Immunoglobulin (Ig) class switch recombination (CSR) involves the breakage and subsequent repair of two DNA sequences, known as switch (S) regions, which flank IgH constant region exons. The resolution of CSR-associated breaks is thought to require the nonhomologous end-joining (NHEJ) DNA repair pathway, but the role of the NHEJ factor DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in this process has been unclear. A new study, in which broken IgH-containing chromosomes in switching B cells were visualized directly, clearly demonstrated that DNA-PKcs and, unexpectedly, the nuclease Artemis are involved in the resolution of switch breaks.

Inciting inflammation: the RAGE about tumor promotion

Dougan, M., Dranoff, G. — 2008-02-18

Mechanisms of innate and adaptive immunity play a pivotal role in the development of cancer. Chronic inflammation can drive tumor development, but antitumor immunity can also restrict or even prevent tumor growth. New data show that feed-forward signals downstream of the receptor for advanced glycation end-products (RAGE) can fuel chronic inflammation, creating a microenvironment that is ideal for tumor formation.

An antidote for Staphylococcus aureus pneumonia?

DeLeo, F. R., Otto, M. — 2008-02-18

Methicillin-resistant Staphylococcus aureus (MRSA) is the leading cause of bacterial infections in the United States. Severe invasive MRSA infections, which include pneumonia, are difficult to treat because the bacteria are resistant to antibiotics. A new report now shows that immunization against -hemolysin (Hla), a cytolytic toxin secreted by most S. aureus strains, protects mice against lethal pneumonia. This finding represents the first successful vaccine strategy for the treatment of staphylococcal pneumonia.