Improving the potency of immune responses is paramount among issues concerning vaccines against deadly pathogens. IL-28B belongs to the newly described interferon lambda (IFN) family of cytokines, and has not yet been assessed for its potential ability to influence adaptive immune responses or act as a vaccine adjuvant. We compared the ability of plasmid-encoded IL-28B to boost immune responses to a multiclade consensus HIV Gag plasmid during DNA vaccination with that of IL-12. We show here that IL-28B, like IL-12, is capable of robustly enhancing adaptive immunity. Moreover, we describe for the first time how IL-28B reduces regulatory T-cell populations during DNA vaccination, whereas IL-12 increases this cellular subset. We also show that IL-28B, unlike IL-12, is able to increase the percentage of splenic CD8 ؉ T cells in vaccinated animals, and that these cells are more granular and have higher antigen-specific cytolytic degranulation compared with cells taken from animals that received IL-12 as an adjuvant. Lastly, we report that IL-28B can induce 100% protection from mortality after a lethal influenza challenge. These data suggest that IL-28B is a strong candidate for further studies of vaccine or immunotherapy protocols. (Blood. 2009;113:5868-5877)

RecQ DNA helicases, including yeast Sgs1p and the human Werner and Bloom syndrome proteins, participate in telomere biology, but the underlying mechanisms are not fully understood. Here, we explore the protein sequences and genetic interactors of Sgs1p that function to slow the senescence of telomerase (tlc1) mutants. We find that the S-phase checkpoint function of Sgs1p is dispensable for preventing rapid senescence, but that Sgs1p sequences required for homologous recombination, including the helicase domain and topoisomerase III interaction domain, are essential. sgs1 and rad52 mutations are epistatic during senescence, indicating that Sgs1p participates in a RAD52-dependent recombinational pathway of telomere maintenance. Several mutations that are synthetically lethal with sgs1 mutation and which individually lead to genome instability, including mus81, srs2, rrm3, slx1 and top1, do not speed the senescence of tlc1 mutants, indicating that the rapid senescence of sgs1 tlc1 mutants is not caused by generic genome instability. However, mutations in SLX5 or SLX8, which encode proteins that function together in a complex that is required for viability in sgs1 mutants, do speed the senescence of tlc1 mutants. These observations further define roles for RecQ helicases and related proteins in telomere maintenance.

No abstract

The HIV-1 Vpr protein is a viral accessory protein that plays a number of important roles during HIV infection. The activities of Vpr are numerous and include the induction of apoptosis, the modulation of cell cycle arrest, as well as control of viral transcription. Study of HIV clones lacking Vpr in vitro and analysis of HIV variants isolated from long-term nonprogressors in vivo highlight the importance of Vpr for viral replication as well as immune suppression and cell death. Vpr may therefore be considered among the most important accessory proteins encoded by HIV.

As the primary site of HIV-1 replication is the mucosa, a desirable feature of a HIV-1 vaccine would be the generation of immune responses at mucosal sites. We created an optimized CCL27 DNA construct as well as optimized SIV gag, pol, and env plasmids for immunizing rhesus macaques. Macaques (n=5/group) were immunized with SIV plasmids +/- CCL27. Both immunization groups had significant IFN-g responses against the encoded SIV antigens (~12,000 SFU/106 PBMCs). CD8+ T cell proliferation as measured by CFSE staining was similar between the groups at ~22%. While systemic immune responses were robust, co-delivery of CCL27 did not adjuvant peripheral responses similar to what was observed in mice. Interestingly, macaques that received CCL27 had greater antigen specific IgA at mucosal sites including bronchial lavage and fecal samples. In addition, CD4+ T cells secreting effector cytokines were enhanced in the CCL27 group at mucosal, but not peripheral sites when compared to the antigenic group alone. The CCL27 group also had more polyfunctional CD8+ T cells in the bronchial lavage than the DNA group post-challenge. These data show that a novel chemokine adjuvant may be capable of targeting immune responses to mucosal sites. This strategy may also be applicable to other diseases than HIV-1 where mucosal immune responses are desirable.