Critical role of regulatory T cells in Th17-mediated minor antigen-disparate rejection

Th17-mediated immune responses have been recently identified as novel pathogenic mechanisms in a variety of conditions; however, their importance in allograft rejection processes is still debated. In this paper, we searched for MHC or minor Ag disparate models of skin graft rejection in which Th17 immune responses might be involved. We found that T cell-derived IL-17 is critical for spontaneous rejection of minor but not major Ag-mismatched skin grafts. IL-17 neutralization was associated with a lack of neutrophil infiltration and neutrophil depletion delayed rejection, suggesting neutrophils as an effector mechanism downstream of Th17 cells. Regulatory T cells (Tregs) appeared to be involved in Th17 reactivity. We found that in vivo Treg depletion prevented IL-17 production by recipient T cells. An adoptive cotransfer of Tregs with naive monospecific antidonor T cells in lymphopenic hosts biased the immune response toward Th17. Finally, we observed that IL-6 was central for balancing Tregs and Th17 cells as demonstrated by the prevention of Th17 differentiation, the enhanced Treg/Th17 ratio, and a net impact of rejection blockade in the absence of IL-6. In conclusion, the ability of Tregs to promote the Th17/neutrophil-mediated pathway of rejection that we have described should be considered as a potential drawback of Treg-based cell therapy.

On The Choice and Impacts of Innovative International Food Assistance Instruments

The rise of new food assistance instruments, including local and regional procurement, cash, and vouchers, has surpassed increase in understanding of the tradeoffs among and impacts of these options relative to traditional food aid. Response choices rarely appear to result from systematic response analyses. Further, impacts along multiple dimensions-timeliness, cost-effectiveness, local market effects, recipient satisfaction, food quality, impact on smallholder suppliers, etc.-may be competing or synergistic. No single food assistance tool is always and everywhere preferable. A growing body of evidence, including the papers in this special section, nonetheless demonstrates the clear value-added of new food assistance instruments. (C) 2013 Elsevier Ltd. All rights reserved.

Market Prices and Food Aid Local and Regional Procurement and Distribution: A Multi-Country Analysis

To date, no research has rigorously addressed the concern that local and regional procurement (LRP) of food aid could affect food prices and food price volatility in food aid source and recipient countries. We assemble spatially and temporally disaggregated data and estimate the relationship between food prices and their volatility and local food aid procurement and distribution across seven countries for several commodities. In most cases, LRP activities have no statistically significant relationship with either local price levels or food price volatility. The few exceptions underscore the importance of market monitoring. (C) 2013 Elsevier Ltd. All rights reserved.

The Impact of Foreign Direct Investment on Economic Growth

Over the past four decades, the number of democracies in the world has increased exponentially. This project considers how democracy and FDI affect economic growth as well as whether the impact of FDI depends on the level of democracy in a country. Thus, I explore two major research questions: 1) Whether increased FDI speeds up economic growth, controlling for political regime type, urbanization and other developmental indicators; and 2) Whether an increase in political freedom helps or hinders economic growth, and specifically whether the impact of FDI varies depending on the political regime in the recipient country. To examine these questions, this paper used data from 150 countries over a period between 1980 and 2010 and utilized several models, testing variables such as institutions, agglomerations, urbanization, FDI and type of political regime, among others, for their impact on economic growth. I found that FDI does have a positive impact on economic growth, and that this impact is often magnified when it interacts with other relevant factors. I also found that, after controlling for other variables, FDI inflows do not have a different impact on economic growth in autocracies than they do in democracies. This may be partially explained by autocratic outliers such as China and the OPEC states, which have recently experienced rapid export-led growth. This suggests that factors such as education could have a greater impact on a country¿s economic growth than does its political system.