In addition to the predictive capacity of pre-vaccination antibody levels, these data suggest a role of immune activation and plasma leptin in antibody response to vaccination, but these observations
were not consistent between vaccines. We are grateful to all the subjects who participated in this research project. We C59 concentration also thank the field staff from MRC Keneba for their assistance with this study. We acknowledge the role of the Nutritional Biochemistry Laboratory, MRC Human Nutrition Research, Cambridge in running the leptin and neopterin assays. This study was financed by the UK Medical Research Council. The vaccines were kindly donated by Sanofi-Pasteur, p38 MAPK apoptosis Lyon, France. “
“Influenza A viruses bear high morbidity and mortality burdens in humans following yearly seasonal epidemics and occasional yet potentially devastating pandemics. Influenza pandemics are caused by influenza A viruses originating from animal reservoirs while influenza A epidemics are caused by their progeny variants—seasonal influenza A viruses—that have adapted to the human species. Animal influenza A viruses are abundant. Avian influenza viruses circulate in numerous species of wild birds, in particular
waterbirds of the orders Anseriformes (mainly geese, ducks and swans) and Charadriiformes (mainly gulls and waders), their natural host reservoirs  and . Influenza A viruses are defined by the subtypes of the hemagglutinin (HA) and neuraminidase (NA) surface glycoproteins. Virtually all combinations of HA and NA subtypes have been found in wild waterbirds, demonstrating the circulation of a large diversity of viruses in these birds. Avian influenza viruses generally cause very mild or sub-clinical intestinal tract infection in wild birds, potentially resulting in low and transient immunity  and , which may allow in these species enough co-circulation of and co-infection with multiple strains and subtypes . Avian influenza viruses are the ancestors of all influenza A viruses found in
other species . They may be transmitted from wild waterbirds to poultry, in which they cause mild or sub-clinical infection . For this reason, they are referred to as low pathogenic avian influenza viruses (LPAIV). LPAIV of the H5 and H7 subtypes may evolve towards highly pathogenic avian influenza viruses (HPAIV) upon transmission into poultry like chickens and turkeys. HPAIV infection usually results in lethal systemic disease in these species. In mammals, occasional transmission of LPAIV from wild or domestic birds results in either sporadic cases of infection, self-limiting epidemics, or sustained epidemics that may eventually develop into recurring epidemics caused by adapted variants.