An evolutionary history of defensins: a role for copy number variation in maximizing host innate and adaptive immune responses

Defensins represent an evolutionary ancient family of antimicrobial peptides that play diverse roles in human health and disease. Defensins are cationic cysteine-containing multifunctional peptides predominantly expressed by epithelial cells or neutrophils. Defensins play a key role in host innate immune responses to infection and, in addition to their classically described role as antimicrobial peptides, have also been implicated in immune modulation, fertility, development, and wound healing. Aberrant expression of defensins is important in a number of inflammatory diseases as well as modulating host immune responses to bacteria, unicellular pathogens, and viruses. In parallel with their role in immunity, in other species, defensins have evolved alternative functions, including the control of coat color in dogs. Defensin genes reside in complex genomic regions that are prone to structural variations and some defensin family members exhibit copy number variation (CNV). Structural variations have mediated, and continue to influence, the diversification and expression of defensin family members. This review highlights the work currently being done to better understand the genomic architecture of the β-defensin locus. It evaluates current evidence linking defensin CNV to autoimmune disease (i.e., Crohn’s disease and psoriasis) as well as the contribution CNV has in influencing immune responses to HIV infection

Intra-Industry Trade in Intermediate Goods and Final Goods in a General Equilibrium Setting

This article develops a dual general equilibrium model to analyze the effects of intra-industry trade in both intermediate goods and final goods on the productivity in the final good production. Intra-industry trade in intermediate goods determines an increase in the number of intermediate good varieties available in the final good production, and intra-industry trade in final goods determines a reduction in the number of adaptations of an intermediate good to the final good production. Thereby, the productivity in the final good production increases. Different shares of intra-industry trade in intermediate goods and final goods in a general equilibrium setting implies that Jones' “magnification effect†and both the Rybczynski theorem and the Stolper-Samuelson theorem are not valid. Copyright Kluwer Academic Publishers 2003intra-industry trade, intermediate goods, international distribution of production, Jones' “magnification effect,†the Rybczynski theorem, the Stolper-Samuelson theorem, general equilibrium,