Long Term Immune Responses to Pandemic Influenza A/H1N1 Infection in Solid Organ Transplant Recipients

In solid organ transplant (SOT) recipients it is unknown if natural infection with influenza confers protection from re-infection with the same strain during the next influenza season. The purpose of this study was to determine if infection with pandemic influenza A/H1N1 (pH1N1) resulted in a long-term immunologic response. Transplant recipients with microbiologically proven pH1N1 infection in 2009/2010 underwent humoral and cell-mediated immunity (CMI) testing for pH1N1 just prior to the next influenza season. Concurrent testing for A/Brisbane/59/2007 was done to rule-out cross-reacting antibody. We enrolled 22 adult transplant patients after pH1N1 infection. Follow up testing was done at a median of 7.4 months (range 5.8–15.4) after infection. After excluding those with cross-reactive antibody, 7/19 (36.8%) patients were seroprotected. Detectable pH1N1-specific CD4+ and CD8+ interferon-γ producing T-cells were found in 11/22 (50%) and 8/22 (36.4%) patients respectively. Humoral immunity had a significant correlation with a CD4 response. This is the first study in transplant patients to evaluate long-term humoral and cellular response after natural influenza infection. We show that a substantial proportion of SOT recipients with previous pH1N1 infection lack long-term humoral and cellular immune responses to pH1N1. These patients most likely are at risk for re-infection

Influenza vaccination for immunocompromised patients: systematic review and meta-analysis from a public health policy perspective.

Immunocompromised patients are vulnerable to severe or complicated influenza infection. Vaccination is widely recommended for this group. This systematic review and meta-analysis assesses influenza vaccination for immunocompromised patients in terms of preventing influenza-like illness and laboratory confirmed influenza, serological response and adverse events

Expression, purification and preliminary crystallographic analysis of dipeptidyl peptidase IV from Porphyromonas gingivalis.

The asaccharolytic periodontopathogen Porphyromonas gingivalis produces membrane-anchored proteases such as dipeptidyl peptidase IV that are involved in the destruction of host periodontal tissue. The extracellular domain of this enzyme was overexpressed in Escherichia coli as an N-terminal His-tag fusion protein, purified using standard metal-affinity chromatography and crystallized using the hanging-drop vapour-diffusion technique in 40% 2-methyl-2,4-pentanediol and 100 mM Tris-HCl pH 8.0. Diffraction data to 2.7 Angstrom resolution were collected using synchrotron radiation. The crystals belong to space group P2(1), with unit-cell parameters a = 117.0, b = 112.9, c = 310.0 Angstrom, beta = 95.0degrees. There are ten molecules per asymmetric unit, indicating a solvent content of 50%. Data were also collected from selenomethionine-derived crystals and structure solution by SAD or MAD is in progress