Single-nucleotide polymorphisms (SNPs) are the most frequent type of variation in the human genome, and they provide powerful tools for a variety of medical genetic studies. In a large-scale survey for SNPs, 2.3 megabases of human genomic DNA was examined by a combination of gel-based sequencing and high-density variation-detection DNA chips. A total of 3241 candidate SNPs were identified. A genetic map was constructed showing the location of 2227 of these SNPs. Prototype genotyping chips were developed that allow simultaneous genotyping of 500 SNPs. The results provide a characterization of human diversity at the nucleotide level and demonstrate the feasibility of large-scale identification of human SNPs.

A novel member of the tumor necrosis factor (TNF) cytokine family, designated TRANCE, was cloned during a search for apoptosis-regulatory genes using a somatic cell genetic approach in T cell hybridomas. The

Stimulated human monocytes release several proteins thought to play a role in inflammation, including interleukin 1, tumor necrosis factor, and plasminogen activator. We have purified another proinflammatory protein that is chemotactic for human neutrophils from conditioned medium of lipopolysaccharide-stimulated monocytes. After a series of steps that included anion-exchange chromatography, gel filtration, and HPLC on cation-exchange and reverse-phase columns, an apparently pure protein was obtained that migrated as a single 7-kDa band on NaDodSO4/polyacrylamide gels under reducing or nonreducing conditions. The amino acid composition of this monocyte-derived neutrophil chemotactic factor was different from that of interleukin 1 and tumor necrosis factor. N-terminal amino acid sequence of the first 42 residues was determined. This portion of the molecule has up to 56% sequence similarity with several proteins that may be involved in host responses to infection or tissue inJury. It is identical to a portion of a sequence deduced from an mRNA induced by staphylococcal enterotoxin treatment of human leukocytes. At the optimal concentration of 10 nM, 50% of neutrophils added to chemotaxis assay wells migrated toward the pure attractant. Potency and efficacy are comparable to that of fMet-Leu-Phe, which is often used as a reference. In contrast to many attractants, the protein was not chemotactic for human monocytes.Accumulation of leukocytes at sites of inflammation is the result of many steps that include vasodilation, leukocyte adherence to vascular endothelium, and directed migration caused by elaboration of chemotactic factors at the initiating locus. The type of leukocyte in the inflammatory infiltrate differs according to the nature of the stimulus and the temporal stage of the response. Therefore, characteristics of a proinflammatory chemoattractant should include (i) production and release in response to the inflammatory stimulus and (ii) at least in some cases the capacity to attract specific types of leukocytes.It was reported that interleukin 1 (IL-1), which is produced by monocytes in response to the inflammatory agent lipopolysaccharide (LPS), is chemotactic for human neutrophils and monocytes (1, 2). Thus, IL-1 appeared to fulfill the first of the above requirements for a proinflammatory attractant. However, we showed that highly purified or recombinant IL-1 has no chemotactic activity for neutrophils and that the neutrophil chemotactic activity in culture fluids of LPSstimulated human monocytes could be separated from IL-1.The activity is due to a basic protein with a molecular mass of about 10 kDa determined by gel filtration (3). We now report the purification to homogeneity of this monocyte-derived neutrophil chemotactic factor (MDNCF), present evidence that the molecule is distinct from monocyte IL-1 and tumor necrosis factor (TNF), and show that it has peptide sequence similarity to several other host-defense cytokines. MDNCF is potentially a mediator of a leukocytespecific inflammatory ...