The molecular basis of how buried human leukocyte antigen polymorphism modulates natural killer cell function

Micropolymorphisms within human leukocyte antigen (HLA) class I molecules can change the architecture of the peptide-binding cleft, leading to differences in peptide presentation and T cell recognition. The impact of such HLA variation on natural killer (NK) cell recognition remains unclear. Given the differential association of HLA-B*57:01 and HLA-B*57:03 with the control of HIV, recognition of these HLA-B57 allomorphs by the killer cell immunoglobulin-like receptor (KIR) 3DL1 was compared. Despite differing by only two polymorphic residues, both buried within the peptide-binding cleft, HLA-B*57:01 more potently inhibited NK cell activation. Direct-binding studies showed KIR3DL1 to preferentially recognize HLA-B*57:01, particularly when presenting peptides with positively charged position (P)Ω-2 residues. In HLA-B*57:01, charged PΩ-2 residues were oriented toward the peptide-binding cleft and away from KIR3DL1. In HLA-B*57:03, the charged PΩ-2 residues protruded out from the cleft and directly impacted KIR3DL1 engagement. Accordingly, KIR3DL1 recognition of HLA class I ligands is modulated by both the peptide sequence and conformation, as determined by the HLA polymorphic framework, providing a rationale for understanding differences in clinical associations

Chinese food threatening the Japanese table : changing perceptions of imported Chinese food in Japan

Stating that imported Chinese food has a negative image in Japan is neither new nor surprising. Conventional explanations of this phenomenon focus on the litany of food scandals associated with imported Chinese food, together with a near-constant wave of scandals in China itself, which have been subject to saturation media coverage in Japan since the turn of the century. However, this chapter argues that the hyperbolic public and media response is disproportionate to the food safety risks associated with the consumption of Chinese food. This chapter starts by assessing two common explanations for the widespread negative perceptions of Chinese food: (1) the development of a consumer awareness in Japan and (2) a heightening risk of consuming Chinese imported foods in the 2000s. The chapter then outlines potential alternative factors, which have also played a key role in the increasingly negative perceptions of Chinese food imports. While there has been an overall increase in the number of reported Chinese food scandals since the 2000s, broader Japanese perceptions of China, the related nature of media coverage of events in China, and the changing nature of Chinese food incidents, among others, are central factors in the development of the perception of a Chinese food threat