Within these groups, we found no convincing data to suggest that the specific viral compositions in influenza vaccines have an effect on cross-reactive neutralizing antibodies to pH1N1 (data not shown). vaccinations than those subjects with no record of vaccination. Although unclear if the result of prior vaccination or disease exposure, these pre-existing antibodies may prevent or reduce disease severity. Outbreaks of 1997 avian influenza H5N1 and 2009 pandemic (p) H1N1 in humans have provided an opportunity to gain insight into cross-reactive ROBO4 immunity. The US armed service periodically collects and stores serum samples from services users linked to medical records.1 We measured cross-reactive antibodies in stored serum to avian influenza H5N1 and 2009 pH1N1 from US military staff and identified factors associated with presence of neutralizing antibodies. Two hundred archived serum samples were from the US Division of Defense Serum Repository. They were representative of a wide cross-section of active armed service staff at the changing times of collection, whereas specific geographic information was not available on the individual selected; the cohort signifies the general US military populace, which is definitely deployed throughout the United States and globally. Fifty samples each were selected from four birth cohorts: (1) 1949, (2) 1960C1965, (3) 1966C1971, and (4) 1972C1977. Within each cohort, 25 samples were collected in the year 2000 (before the intro of intranasal live attenuated influenza vaccine [LAIV]), and 25 samples were collected in 2008 (where 51% of donors experienced received LAIV). It has been suggested that LAIV elicits cross-reactive immunity.2,3 The samples were all collected before the outbreak Mycophenolate mofetil (CellCept) of 2009 pH1N1, and there have not been any reported outbreaks of H5N1 in US armed service personnel. Assays used to measure antibodies included a hemagglutination inhibition (HI) assay and a neuraminidase inhibition (NI) assay.4 Viral neutralization by antibodies against H5N1 and 2009 pH1N1 was assessed by influenza (H5) pseudotyped lentiviral particle-based (H5pp)5 and microneutralization assays, respectively. Electronic medical and vaccination records from the Defense Medical Surveillance System (DMSS), which captured records before the serum sample date, were linked to samples and compared with the results.1 The odds ratios (ORs) and 95% confidence intervals (95% CIs) of univariate and multivariate binary logistic regression analyses were used to determine the association between donor characteristics and positive antibody responses. A multiple logistic regression model was constructed, and it included self-employed variables having a value of 0.05 in univariate logistic regression. A value of 0.05 was considered to indicate statistical significance. SPSS 12.0 for Windows (SPSS Inc., Chicago, IL) was used to perform all Mycophenolate mofetil (CellCept) statistical analysis. Cross-reactivity is definitely summarized in Table 1 . Although HI assay titers to H5N1 were uniformly Mycophenolate mofetil (CellCept) low (0.5%), neutralizing antibodies were considerably higher: 14% for the more sensitive H5pp assay5 and 22.5% for the NI assay. H5pp and NI antibody titers to H5N1 were equally distributed among birth cohorts and did not differ substantially based on history of vaccination or Mycophenolate mofetil (CellCept) prior respiratory infections. Of those individuals with neutralizing antibodies to H5N1 (= 28), 32.1% also had neutralizing antibodies to pH1N1, whereas 19.3% of those individuals with any H5N1-specific antibody response also experienced neutralizing antibodies to pH1N1 (Table 1). Table 1 Serum cross-reactivity to avian influenza H5N1and 2009 pH1N1 indicating the percentage of subjects considered to have positive titers and the geometric imply titers for each assay = 33), 27.3% also had neutralizing antibodies to H5N1, whereas 28.9% of those individuals with any pH1N1-specific antibody response also experienced neutralizing antibodies to H5N1. Univariate associations between the prevalence of cross-reactive antibodies to H5N1 and 2009 pH1N1 and self-employed variables, including 12 months of birth, serum collection 12 months, sex, and seasonal influenza vaccination history, are demonstrated in Table 2 . The odds of having cross-neutralizing antibodies against 2009 pH1N1 were threefold higher in those donors who received.
Within these groups, we found no convincing data to suggest that the specific viral compositions in influenza vaccines have an effect on cross-reactive neutralizing antibodies to pH1N1 (data not shown)