1. ¹Department of Bioinformatics, Genentech, Inc., South San Francisco, CA, USA
2. ²Department of Immunology, Genentech, Inc., South San Francisco, CA, USA
3. ³Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA

Correspondence: Dr HF Clark, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA. E-mail: hclark@gene.com

Received 29 July 2004; Revised 1 November 2004; Accepted 8 December 2004; Published online 24 March 2005.

Abstract

Immune cell-specific expression is one indication of the importance of a gene's role in the immune response. We have compiled a compendium of microarray expression data for virtually all human genes from six key immune cell types and their activated and differentiated states. Immune Response In Silico (IRIS) is a collection of genes that have been selected for specific expression in immune cells. The expression pattern of IRIS genes recapitulates the phylogeny of immune cells in terms of the lineages of their differentiation. Gene Ontology assignments for IRIS genes reveal significant involvement in inflammation and immunity. Genes encoding CD antigens, cytokines, integrins and many other gene families playing key roles in the immune response are highly represented. IRIS also includes proteins of unknown function and expressed sequence tags that may not represent genes. The predicted cellular localization of IRIS proteins is evenly distributed between cell surface and intracellular compartments, indicating that immune specificity is important at many points in the signaling pathways of the immune response. IRIS provides a resource for further investigation into the function of the immune system and immune diseases.