1. ¹ Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands,
2. ² Centre for Experimental Immunology, Lions Eye Institute, Nedlands,
3. ³ Discipline of Microbiology, School of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Western Australia, Australia
4. ⁴ Division of Rheumatology and Immunology, Department of Internal Medicine, University of Virginia Health System, Charlottesville, Virginia, USA

Correspondence: Dr Anthony Scalzo, Centre for Experimental Immunology, Lions Eye Institute, 2 Verdun Street, Nedlands, WA 6009, Australia. Email: scals@cyllene.uwa.edu.au

Received 20 September 2004; Accepted 18 October 2004; Published online 28 February 2005.

Abstract

The NK gene complex (NKC) on mouse chromosome 6 encodes receptors that are expressed on NK cells, such as Ly49H, and is involved in regulating NK cell control of virus infections, such as murine cytomegalovirus (MCMV). In the present study, we investigated the level of allelic heterogeneity in NKC loci in populations of outbred wild mice. This work revealed extensive levels of heterogeneity within two wild mouse populations. Analysis of MCMV replication in a population of specific pathogen-free outbred wild mice revealed that low viral titres, which are normally associated with the Cmv1 ^r allele of the Cmv1 host resistance locus, were not prevalent in the mice tested. Hence, NKC-mediated resistance associated with Cmv1 ^r/Ly49H-like effects was rare in this population. Overall, these data indicate that the NKC region is highly polymorphic and thus it is very likely that it confers on mice sufficient variability to cope with infection by a range of pathogens.