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Summary Malaria is a highly prevalent disease caused by infection by Plasmodium spp., which infect hepatocytes and erythrocytes. Blood-stage infections cause devastating symptoms and can persist for years. Antibodies and CD4 + T cells are thought to protect against blood-stage infections. However, there has been considerable difficulty in developing an efficacious malaria vaccine, highlighting our incomplete understanding of immunity against this disease. Here, we used an experimental rodent malaria model to show that PD-1 mediates up to a 95% reduction in numbers and functional capacity of parasite-specific CD8 + T cells. Furthermore, in contrast to widely held views, parasite-specific CD8 + T cells are required to control both acute and chronic blood-stage disease even when parasite-specific antibodies and CD4 + T cells are present. Our findings provide a molecular explanation for chronic malaria that will be relevant to future malaria-vaccine design and may need consideration when vaccine development for other infections is problematic.

Human enterovirus 71 (EV71) has become a major public health threat across Asia Pacific. The virus causes hand, foot, and mouth disease which can lead to neurological complications in young children. There are no specific antivirals or vaccines against EV71 infection. The major neutralizing epitope of EV71 is located in the carboxy-terminal half of the VP1 protein at amino acid positions 215-219 (Lim et al., 2012). To study the immunogenicity of VP1 we have developed a baculovirus vector which displays VP1 as a type II transmembrane protein, providing an accessible C-terminus. Immunization of mice with this recombinant baculovirus elicited neutralizing antibodies against heterologous EV71 in an in vitro microneutralization assay. Passive protection of neonatal mice confirmed the prophylactic efficacy of the antisera. Additionally, EV71 specific T cell responses were stimulated. Taken together, our results demonstrate that the display of VP1 as a type II transmembrane protein efficiently stimulated both humoral and cellular immunities.

Loloatin C is a cyclic cationic antimicrobial peptide which is active against Gram positive as well as certain Gram negative bacteria. Unfortunately, it is equally potent against human erythrocytes. To probe the structure-activity relationship of this promising antibiotic peptide, amino acid substitution and/or incorporation of a constraint sugar amino acid dipeptide isoster has been applied. Six new derivatives have been synthesized using SPPS and their solution structure investigated using NMR studies. Finally, the antimicrobial and the hemolytic activities have been determined. © 2009 Elsevier Ltd. All rights reserved.

Suitably protected linear precursors of cyclic PNAs can be readily obtained by BOP/DiPEA coupling of the corresponding sub-monomers. Conversion of the linear PNA dimers into the pentafluorophenyl esters allows cyclization by intramolecular attack of the deprotected primary amino function under diluted conditions. After removal of the secondary amino protecting group(s), installation of the required nucleobase-acetyl function(s) affords cyclic PNAs. In addition, the latter compounds can be prepared following a direct coupling strategy.