Influenza nucleoprotein delivered with aluminium salts protects mice from an influenza virus that expresses an altered nucleoprotein sequence

Influenza virus poses a difficult challenge for protective immunity. This virus is adept at altering its surface proteins, the proteins that are the targets of neutralizing antibody. Consequently, each year a new vaccine must be developed to combat the current recirculating strains. A universal influenza vaccine that primes specific memory cells that recognise conserved parts of the virus could prove to be effective against both annual influenza variants and newly emergent potentially pandemic strains. Such a vaccine will have to contain a safe and effective adjuvant that can be used in individuals of all ages. We examine protection from viral challenge in mice vaccinated with the nucleoprotein from the PR8 strain of influenza A, a protein that is highly conserved across viral subtypes. Vaccination with nucleoprotein delivered with a universally used and safe adjuvant, composed of insoluble aluminium salts, provides protection against viruses that either express the same or an altered version of nucleoprotein. This protection correlated with the presence of nucleoprotein specific CD8 T cells in the lungs of infected animals at early time points after infection. In contrast, immunization with NP delivered with alum and the detoxified LPS adjuvant, monophosphoryl lipid A, provided some protection to the homologous viral strain but no protection against infection by influenza expressing a variant nucleoprotein. Together, these data point towards a vaccine solution for all influenza A subtypes

A Distinctive γδ T Cell Repertoire in NOD Mice Weakens Immune Regulation and Favors Diabetic Disease

Previous studies in mice and humans suggesting that γδ T cells play a role in the development of type 1 diabetes have been inconsistent and contradictory. We attempted to resolve this for the type 1 diabetes-prone NOD mice by characterizing their γδ T cell populations, and by investigating the functional contributions of particular γδ T cells subsets, using Vγ-gene targeted NOD mice. We found evidence that NOD Vγ4+ γδ T cells inhibit the development of diabetes, and that the process by which they do so involves IL-17 production and/or promotion of regulatory CD4+ αβ T cells (Tregs) in the pancreatic lymph nodes. In contrast, the NOD Vγ1+ cells promote diabetes development. Enhanced Vγ1+ cell numbers in NOD mice, in particular those biased to produce IFNγ, appear to favor diabetic disease. Within NOD mice deficient in particular γδ T cell subsets, we noted that changes in the abundance of non-targeted T cell types also occurred, which varied depending upon the γδ T cells that were missing. Our results indicate that while certain γδ T cell subsets inhibit the development of spontaneous type 1 diabetes, others exacerbate it, and they may do so via mechanisms that include altering the levels of other T cells

NY1682 infection does not prime T cells specific for immunodominant epitopes from PR8’s NP.

<p>B6 mice were infected (bottom) or not (top) with NY1682 i.n. and 25 days later the percentages of D^b/PA_224–38, D^b/NP_366–74 CD8 T cells, or IA^b/NP_311–25 CD4 in the MLN were examined (A). The numbers are the percentages of tetramer+CD44^hi cells out of gated CD8+ or CD4+ live cells that were also dump negative. The serum from these animals was tested for the presence of IgG1 and IgG2c antibody that bound to recombinant PR8 NP with each line representing one mouse (B).</p

Immunization with PR8’s NP and alum primes protective immunity to NY1682.

<p>B6 mice were injected i.m. in both hind-legs with PBS (closed triangles) or a total of 10 µg of NP and 100 µg of alum with (open squares) or without (closed squares) 10 µg of MPL. At least 70 days later, these animals were infected with NY1682 i.n. The mice were weighed daily and the percent of original weight of each mouse calculated for each day. The data are combined from two experiments with 4–5 mice per group (A). These mice were bled one day prior to infection with NY1682 or 5 days following infection. The relative units of NP specific IgG1 and IgG2c present in the serum were determined using a NP specific ELISA (B). The percentages (C) or numbers (D) of D^b/NP_366–74 tetramer+ cells present in one lung lobe of these and naïve control animals were examined. In A, significant differences between the PBS control mice infected with NY1682 and those first immunized with PR8’s NP and alum are indicated with *(p<0.05) and **(p<0.01). No significant differences between PBS control mice and those first immunized with PR8’s NP and alum and MPL were found. In C, cells were gated on live CD8+ lymphocytes that were dump negative. Representative plots are shown from 1 experiment with 4 mice per group with numbers in the plot indicating the percentages of D^b/NP_366–74 tetramer+ out of gated live CD8+ cells. In D, each point represents a mouse and the line shows the mean of the group. The X-axis is set at the level of background staining.</p

The NP amino acid sequence from PR8 and NY1682 influenza viruses differ in known epitopes.

<p>Sequence alignment for NP proteins from PR8 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061775#pone.0061775-Grimm1" target="_blank">[46]</a> and NY1682 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061775#pone.0061775-Zhou1" target="_blank">[20]</a>. The IA^b and D^b binding peptides are highlighted in red and green respectively.</p