Target-rich Environment Research Articles

Human Cytomegalovirus-Encoded Immune Modulators Partner To Downregulate Major Histocompatibility Complex Class I Molecules

Throughout the course of natural evolution with its host, the human cytomegalovirus (HCMV) has developed a variety of strategies to avoid immune recognition and clearance. The major histocompatibility complex (MHC) class I antigen presentation pathway is a major target of the virus. HCMV encodes at least six gene products that modulate the processing of endoplasmic reticulum (ER)-resident MHC class I molecules. Here, we show that two virus-encoded proteins, US2 and US3, coordinate their functions toward the common goal of attenuating class I protein surface expression. In cells stably expressing both US2 and US3, class I molecules were almost completely downregulated from the cell surface. In addition, pulse-chase analysis revealed that the proteasome-dependent turnover of class I molecules occurs more rapidly in cells expressing both US2 and US3 than either US2 or US3 alone. The ability of US3 to retain class I molecules in the ER produces a target-rich environment for US2 to mediate the destruction of class I heavy chains. In fact, expression of US3 enhanced the association between US2 and class I molecules, thus encouraging their dislocation and degradation. This immune evasion strategy ensures that viral antigens are not presented on the cell surface during the early phase of HCMV infection, a critical time of replication and viral proliferation.

TERRORISM AND AFRICA

This article first looks at the relationship between international terrorism and terrorism in Africa. Since sub-state terrorism is already endemic to Africa, the future threat potential in the continent lies in a complex mixture of sub-national and international terrorism. Africa may come to play a central role in international terrorism. The motivation, means and targets all exist and these opportunities will not go unheeded for much longer. Africa presents both a facilitating environment and a target-rich environment for terrorists that seek to attack the United States, and indeed the global system. The article concludes with some remarks on counter-strategies.

Target Rich Environment

Target Rich Environment

A Comparison of Audiences at Selected Hallmark Events in the United States

Hallmark events offer target-rich environments for marketers. Audience characteristics at a variety of events are described. These characteristics include demographics, lifestyles, satisfaction, recall and product consumption. Similarities and differences among the audiences are noted. Such information should be useful to marketing and promotion managers in choosing events for participation and in creating messages specifically targeted to the events' audiences.