Induction of Germinal Centers by MMTV Encoded Superantigen on B Cells

It has not been established whether an endogenous superantigen (SAg) expressed on B cells can induce germinal centers (GCs). An interesting model is that of mammary tumor virus encoded viral SAgs, which induce vigorous T cell proliferation and are predominantly expressed on activated B cells. We have used this model to analyze the possibility that direct stimulation of Mtv7+ DBA/2 B cells by vSAg-responsive (Vβ6+) BALB/c T cells can give rise to GCs. Injection of BALB/c SCID mice iv with 2 × 106 DBA/2 B cells, together with LPS, followed by 2 × 106 BALB/c T cells induces numerous large splenic GCs within 3–5 days. The GCs are still large on day 7, but are very much reduced by day 10. B cell activation with LPS is needed for this effect. These GCs form in spite of the apparent absence of follicular dendritic cells (FDCs) as judged by staining for several FDC surface markers. Control mice receiving either BALB/c T or DBA/2 B cells + LPS alone or DBA/2 T + B cells + LPS fail to exhibit any GCs on days 3–7. Numerous small clusters of PNA+ cells, but few large GCs are observed when TNF-R(p55)-Ig is also injected, whereas LTβR-Ig treatment impeded the formation of aggregations of these cells even further, leaving scattered PNA+ single cells and very small clumps throughout the white pulp of the spleens. Anti-TNFα had no effect. These results suggest that endogenous vSAg mediated GC formation is independent of antigen trapping by FDCs

Investigating the Effect of Exchange Rate Changes on the People's Republic of China's Processed Exports

Many argue that the yuan needs to appreciate to rebalance the People's Republic of China's trade. However, empirical evidence on the effects of a CNY appreciation on the People's Republic of China's exports has been mixed for the largest category of exports, processed exports. Since much of the value-added of these goods comes from parts and components produced in Japan, the Republic of Korea, and other East Asian supply chain countries, it is important to control for exchange rate changes in these countries. Employing dynamic ordinary least squares, or DOLS, techniques and quarterly data, this paper finds that exchange rate appreciations across supply chain countries would cause a much larger drop in processed exports than a unilateral appreciation of the yuan

Investigating the Effect of Exchange Rate Changes on Transpacific Rebalancing

This paper investigates the role that exchange rate changes can play in rebalancing transpacific trade. It presents evidence from a gravity model indicating that the exports from the People's Republic of China (PRC) to the United States (US) are a key outlier in the global economy and that imbalances between the PRC and the US have remained large during the financial crisis that began in September 2008. It then reports that an appreciation of the yuan against the dollar would be required to rebalance bilateral trade between the US and the PRC. In the case of multilateral trade between the US and the rest of the world, on the other hand, the evidence indicates that a depreciation of the dollar would not substantially reduce the US global trade deficit. In the case of Asia's exports, results presented here and elsewhere indicate that: (i) sophisticated exports produced within regional production networks depend on exchange rates throughout the region; (ii) labor-intensive exports from developing Asian countries are strongly influenced by each country's own exchange rate; (iii) developing Asian countries compete extensively with each other in exports to third markets; (iv) a currency appreciation in developing Asia would increase capital and consumption goods imports; and (v) exchange rate volatility deters parts and components trade in Asia. These findings imply that Asia and the rest of the world would benefit if East Asian currencies could appreciate together against external currencies while maintaining relative currency stability within the region

Understanding Foreign Direct Investment in East Asia

We recount East Asia's experience with foreign direct investment (FDI). We document that, contrary to the Rybczynski theorem, capital flows in the region cause the host country's labor-intensive industry to expand and its capital-intensive industry to decline. We also present narrative evidence that sheds light on how FDI is affected by the host's country's locational advantages, whether Asian FDI is footloose, and how the PRC has become the center of Factory Asia. Finally, we show that the evolution of production networks in the region can be explained partly by changes in the service cost of linking geographically separated production blocks relative to the cost saving arising from slicing up the value chain