The HIV-1 envelope trimer (Env) is the target of broadly neutralizing antibodies and is being explored as a vaccine candidate to elicit protective antibodies. One of the most promising antigenic and structural mimics of HIV-1 Env is the SOSIP.664-stabilized soluble trimer from the clade A strain BG505, which is preferentially recognized by broadly neutralizing antibodies. Trimer immunization elicits high-titer neutralization of the autologous tier 2 BG505 strain; however, breadth is limited, and substantial interest has focused on understanding and improving trimer immunogenicity. We sought to improve the antigenic specificity of BG505 SOSIP.664 by reducing recognition of the variable loop 3 (V3) region, which elicits only weakly neutralizing antibodies. To stabilize the trimer in its prefusion closed conformation, we complexed trimeric BG505 SOSIP.664 with the antigen-binding fragment (Fab) of PGT145, a broadly neutralizing quaternary-structure-specific antibody. Compared to the ligand-free trimer, the PGT145 Fab-BG505 SOSIP.664 complex displayed increased melting temperature stability and reduced V3 recognition. In guinea pigs, immunization with the PGT145 Fab-BG505 SOSIP.664 complex elicited ϳ100-fold lower V3-directed binding and neutralization titers than those obtained with ligand-free BG505 SOSIP.664. Both complexed and ligand-free BG505 SOSIP.664 elicited comparable neutralization of the autologous BG505 virus, and in both cases, BG505 neutralization mapped to the outer domain of gp120 for some guinea pigs. Our results indicate that it is possible to reduce immune recognition of the V3 region of the trimer while maintaining the antigenic profile needed to induce autologous neutralizing antibodies. These data suggest that appropriate modifications of trimer immunogens could further focus the immune response on key neutralization epitopes. A s the sole viral antigen on the surfaces of HIV-1 virions, the envelope trimer (Env) mediates virus entry into host cells and is the target of virus-directed neutralizing antibodies (NAbs) (1-3; reviewed in references 4 and 5). Env comprises three gp120 receptor-binding subunits noncovalently associated with three gp41 transmembrane subunits. Similar to the transmembrane subunits of other type 1 fusion proteins, the gp41 subunit transitions between prefusion, intermediate, and postfusion states as part of its entry-related fusion of viral and target cell membranes (2, 6, 7). However, unlike other type 1 fusion machines, HIV-1 Env transitions between at least three distinct prefusion states (8). One of these, the prefusion closed conformation, is the target of most broadly neutralizing antibodies (2,3,5,8,9), and it has been proposed that HIV-1 Env fixed in the prefusion closed state may be a preferred HIV-1 immunogen (2,3,5,9,10).A soluble recombinant glycoprotein mimic of the HIV-1 spike, named BG505 SOSIP.664 for the HIV-1 strain (BG505) and the stabilizing mutations involved (SOSIP.664), was recently described (11). An important antigenic characteristic of t...

A major problem hindering the development of autograft alternatives for repairing peripheral nerve injuries is immunogenicity. We have previously shown successful regeneration in transected rat sciatic nerves using conduits filled with allogeneic dorsal root ganglion (DRG) cells without any immunosuppression. In this study, we re-examined the immunogenicity of our DRG neuron implanted conduits as a potential strategy to overcome transplant rejection. A biodegradable NeuraGen® tube was infused with pure DRG neurons or Schwann cells cultured from a rat strain differing from the host rats and used to repair 8 mm gaps in the sciatic nerve. We observed enhanced regeneration with allogeneic cells compared to empty conduits 16 weeks post-surgery, but morphological analyses suggest recovery comparable to the healthy nerves was not achieved. The degree of regeneration was indistinguishable between DRG and Schwann cell allografts although immunogenicity assessments revealed substantially increased presence of Interferon gamma (IFN-γ) in Schwann cell allografts compared to the DRG allografts by two weeks post-surgery. Macrophage infiltration of the regenerated nerve graft in the DRG group 16 weeks post-surgery was below the level of the empty conduit (0.56 fold change from NG; p<0.05) while the Schwann cell group revealed significantly higher counts (1.29 fold change from NG; p<0.001). Major histocompatibility complex I (MHC I) molecules were present in significantly increased levels in the DRG and Schwann cell allograft groups compared to the hollow NG conduit and the Sham healthy nerve. Our results confirmed previous studies that have reported Schwann cells as being immunogenic, likely due to MHC I expression. Nerve gap injuries are difficult to repair; our data suggest that DRG neurons are superior medium to implant inside conduit tubes due to reduced immunogenicity and represent a potential treatment strategy that could be preferable to the current gold standard of autologous nerve transplant.

Small-t antigen produced in bacteria interacted with two animal cell proteins with molecular weights of 56,000 and 32,000, as did the viral antigen from infected cells. Demonstration of this specific interaction required the enrichment of native, monomeric small-t antigen from extracts in which much of the small-t antigen was highly aggregated.

Inappropriate daily lab testing can have adverse effects on patients, including anemia, pain, and interruption of sleep. We implemented a student-led, multifaceted intervention featuring clinician education, publicity campaign, gamification, and system changes, including a novel nurse-driven protocol to reduce unnecessary daily lab testing in a teaching hospital. We applied a quasi-experimental interrupted time series design with a segmented regression analysis to estimate changes before and after our 14-month intervention with a comparison to a control surgical unit. There was an increasing trend in the baseline period, which was mitigated by the intervention (postintervention effect estimate -0.04 labs per patient day/month, p < .05), which was not seen in the control unit. Estimated cost savings was $94,269 ($6,734/month). A student-led, multidisciplinary campaign involving nurse-driven pathway, education, publicity, gamification, and system changes was effective in reducing daily lab testing.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.