Background Obesity is an independent risk factor for morbidity and mortality from pandemic influenza H1N1. Influenza is a significant public health threat, killing an estimated 250,000 to 500,000 worldwide each year. More than one in ten of the world’s adult population is obese and more than two-thirds of the US adult population is overweight or obese. No studies have compared humoral or cellular immune responses to influenza vaccination in healthy weight, overweight and obese populations despite clear public health importance. Objective The study employed a convenience sample to determine the antibody response to the 2009–2010 inactivated trivalent influenza vaccine (TIV) in healthy weight, overweight and obese participants at one and 11 months post vaccination. In addition, activation of CD8+ T cells and expression of interferon-γ and granzyme B were measured in influenza-stimulated peripheral blood mononuclear cell cultures. Results BMI correlated positively with higher initial fold increase in IgG antibodies detected by ELISA to TIV, confirmed by HAI antibody in a subset study. However, eleven months post vaccination, higher BMI was associated with a greater decline in influenza antibody titers. PBMC’s challenged ex vivo with vaccine strain virus demonstrated that obese individuals had decreased CD8+ T cell activation and decreased expression of functional proteins compared with healthy weight individuals. Conclusion These results suggest obesity may impair the ability to mount a protective immune response to influenza virus.

In contrast to the cell division machineries of bacteria, euryarchaea, and eukaryotes, no division components have been identified in the second main archaeal phylum, Crenarchaeota. Here, we demonstrate that a three-gene operon, cdv, in the crenarchaeon Sulfolobus acidocaldarius, forms part of a unique cell division machinery. The operon is induced at the onset of genome segregation and division, and the Cdv proteins then polymerize between segregating nucleoids and persist throughout cell division, forming a successively smaller structure during constriction. The cdv operon is dramatically down-regulated after UV irradiation, indicating division inhibition in response to DNA damage, reminiscent of eukaryotic checkpoint systems. The cdv genes exhibit a complementary phylogenetic range relative to FtsZ-based archaeal division systems such that, in most archaeal lineages, either one or the other system is present. Two of the Cdv proteins, CdvB and CdvC, display homology to components of the eukaryotic ESCRT-III sorting complex involved in budding of luminal vesicles and HIV-1 virion release, suggesting mechanistic similarities and a common evolutionary origin.he Archaea constitute a separate domain of life that has evolved in parallel with Bacteria and Eukarya (1). The archaeal domain is currently divided into two main lineages, the Crenarchaeota and the Euryarchaeota, each of which comprises several distinct classes of organisms that thrive in a wide variety of environments. Whereas several aspects of archaeal biology appear to be unique, certain traits resemble those in eukaryotes, including the machineries that govern information storage, maintenance, and processing.Several features of archaeal cell cycle progression have been elucidated in considerable detail including the overall organization of the cell cycle in certain species, and regulatory and mechanistic aspects of the replication process (2, 3). Conversely, the genome segregation machinery remains essentially uncharacterized in this domain. In archaeal species belonging to the Euryarchaeota phylum, and in bacteria, cell division is mediated by FtsZ protein filaments that form a constricting ring structure (4). In eukaryotes, division occurs with the help of a contractile actin-myosin ring or, in plant cells, by septum formation at a site initially marked by actin and microtubules (5). In contrast to bacteria, euryarchaea, and eukaryotes, no cell division components have been identified in the second main archaeal phylum, Crenarchaeota (2).Here, we report on the identification of key components of the cell division system in the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius, describe intracellular structures that are formed by the gene products during genome segregation and division, and show that the operon is subject to a checkpoint-like regulation. We also demonstrate that the division machinery is present in all crenarchaeal orders except Thermoproteales, and that it is related to the eukaryotic ESCRT-III sorting complex.

The world is now experiencing an epidemic of obesity. Although the effects of obesity on the development of metabolic and cardiovascular problems are well studied, much less is known about the impact of obesity on immune function and infectious disease. Studies in obese humans and with obese animal models have repeatedly demonstrated impaired immune function, including decreased cytokine production, decreased response to antigen/mitogen stimulation, reduced macrophage and dendritic cell function, and natural killer cell impairment. Recent studies have demonstrated that the impaired immune response in the obese host leads to increased susceptibility to infection with a number of different pathogens such as community-acquired tuberculosis, influenza, Mycobacterium tuberculosis, coxsackievirus, Helicobacter pylori and encephalomyocarditis virus. While no specific mechanism has been defined for the decreased immune response to infectious disease in the obese host, several obesity-associated changes such as excessive inflammation, altered adipokine signaling, metabolic changes and even epigenetic regulation could affect the immune response. This review will discuss what is currently known about the relationship between obesity and infectious disease.

The global obesity epidemic combined with yearly influenza outbreaks and potential for a pandemic makes it crucial to determine how protection from influenza differs in an obese host. In contrast to a vaccine antibody response which recognizes surface proteins, memory T cells generated during a primary infection target internal viral proteins and are protective against heterologous strains. As our prior work demonstrated that obese mice have an impaired primary response to influenza virus infection, we hypothesized that obese mice would also have an impaired memory response to a secondary influenza infection. To test this hypothesis, obese and lean mice were infected with influenza X‐31. At 31 days post infection, mice were challenged with a lethal dose of a different strain, influenza A/PR/8. While lean mice were protected from lethal infection, obese mice had 25% mortality, increased lung pathology and virus titers, reduced antiviral cytokine expression, and decreased and delayed adaptive immune cytokine expression following secondary challenge. These results indicate that memory response to influenza in obese mice is significantly altered and ineffective and obesity may hinder the generation or function of these protective cells. These results suggest obese populations are at risk for impaired immune memory response, which has significant public health implications for current vaccination protocols. Grant Funding Source DK56350