T-cells

Expression of cutaneous lymphocyte-associated antigen by CD8+ T cells specific for a skin-tropic virus.Koelle, D. M. et al. J. Clin. Invest. 110, 537–548 (2002)

In this study, the trafficking of antigen-specific CD8+ T cells to the skin was investigated. Herpes simplex virus type 2 (HSV2) causes periodic lytic infection of the skin and genital mucosa. Cutaneous lymphocyte-associated antigen (CLA) is a carbohydrate moiety that decorates P-selectin glycoprotein ligand-1 on T cells. A CLA-like molecule can bind E-selectin, an adhesion molecule that is expressed by endothelial cells in inflamed skin and mucosa, leading to the rolling and adhesion of CLA-expressing cells on the vascular endothelium. Koelle et al. investigated the role of this CLA–E-selectin interaction in the trafficking of HSV2-specific T cells to the skin in vivo. This is the first report of the expression of tissue-homing molecules on virus-specific CD8+ T cells.

Vaccines

A pantothenate auxotroph of Mycobacterium tuberculosis is highly attenuated and protects mice against tuberculosis.Sambandamurthy, V. K. et al. Nature Med. 9 September 2002 (DOI 10.1038/nm765)

The global incidence of tuberculosis is increasing, and although attenuated vaccines exist, there is a great need for improved vaccines. Here, Sambandamurthy et al. describe the development of an attenuated Mycobacterium tuberculosis vaccine. This candidate vaccine is an auxotrophic mutant of M. tuberculosis that cannot synthesize pantothenic acid (vitamin B5). Attenuation was assessed by infection of immunocompromised mice; mice infected with the pantothenate mutant survived longer than mice that were infected with either Mycobacterium bovis bacillus Calmette-Guerin (BCG) or virulent M. tuberculosis. Importantly, subcutaneous injection of the pantothenate mutant protected mice against challenge with virulent M. tuberculosis. These results indicate that this attenuated, persisting form of M. tuberculosis is a possible vaccine candidate for further development.

Viral immunity

Critical role for STAT4 activation by type 1 interferons in the interferon-γ response to viral infection.Nguyen, K. B. et al. Science 297, 2063–2066 (2002)

Type I (IFN-α and -β) and type II (IFN-γ) interferons are crucial for innate immunity and they have antiviral properties. The immunoregulatory functions of type I IFNs, particularly their ability to regulate IFN-γ production, are not well understood. Here, Nguyen et al. investigate this, and show that during viral infections in mice, type I IFNs activate signal transducer and activator of transcription 4 (STAT4) directly, which then binds to the proximal IFN-γ promoter, resulting in the increased production of IFN-γ.