Background. North Americans report insufficient moderate-to-vigorous physical activity (MVPA) and ample sedentary behaviors (SBs), suggesting possible barriers to an active lifestyle. This study ...compared self-reported MVPA and SB before and during COVID-19 “Stay-at-Home” restrictions as a potential barrier across North America. Methods: Questionnaires were distributed from 21 April to 9 May 2020. ANOVAs compared data overall and by group (age, sex, race, income, education, employment status). Results: During restrictions, 51.4% (n = 687) of the 1336 responses (991 female, 1187 Caucasian, 634 18–29 years) shifted to work from home and 12.1% (n = 162) lost their job. Overall, during restrictions, 8.3% (n = 110) fewer reported work-related MVPA (−178.6 ± 20.9 min/week). Similarly, 28.0% (n = 374) fewer reported travel-related MVPA, especially females and younger age groups. While the 7.3% (n = 98) fewer reporting recreational MVPA was not statistically significant (−30.4 ± 11.5 min/week), there was an increase in SB (+94.9 ± 4.1 min/week) in all groups, except the oldest age group (70+ years). Locomotive activities and fitness class remained the predominant MVPA mode. Of those reportedly using facilities (68%; n = 709) before COVID, 31.3% (n = 418) would not return due to it “being unsafe”. Conclusion: While barriers related to pandemic restrictions had a negative short-term impact on MVPA and SB in North America, the long-term impact is unknown.
The HIV fusion peptide (FP) is a promising vaccine target. FP-directed monoclonal antibodies from vaccinated macaques have been identified that neutralize up to ∼60% of HIV strains; these ...vaccinations, however, have involved ∼1 year with an extended neutralization-eclipse phase without measurable serum neutralization. Here, in 32 macaques, we test seven vaccination regimens, each comprising multiple immunizations of FP-carrier conjugates and HIV envelope (Env) trimers. Comparisons of vaccine regimens reveal FP-carrier conjugates to imprint cross-clade neutralizing responses and a cocktail of FP conjugate and Env trimer to elicit the earliest broad responses. We identify a signature, appearing as early as week 6 and involving the frequency of B cells recognizing both FP and Env trimer, predictive of vaccine-elicited breadth ∼1 year later. Immune monitoring of B cells in response to vaccination can thus enable vaccine insights even in the absence of serum neutralization, here identifying FP imprinting, cocktail approach, and early signature as means to improve FP-directed vaccine responses.
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•Immunization in 32 rhesus macaques reveals FP priming to imprint cross-clade responses•Identifying an early B cell signature predictive of vaccine outcome•Priming with a cocktail of FP and trimer elicits the earliest neutralizing responses•B cell immune monitoring enables vaccine insights, even without serum neutralization
Immune monitoring of B cells in response to vaccination can enable early insights, even in the absence of serum neutralization. Cheng et al. observe an early B cell signature in NHPs predictive of the vaccine outcome, with priming of HIV FP imprinting cross-clade neutralizing FP-directed vaccine responses.
Soluble “SOSIP”-stabilized envelope (Env) trimers are promising HIV-vaccine immunogens. However, they induce high-titer responses against the glycan-free trimer base, which is occluded on native ...virions. To delineate the effect on base responses of priming with immunogens targeting the fusion peptide (FP) site of vulnerability, here, we quantify the prevalence of trimer-base antibody responses in 49 non-human primates immunized with various SOSIP-stabilized Env trimers and FP-carrier conjugates. Trimer-base responses account for ∼90% of the overall trimer response in animals immunized with trimer only, ∼70% in animals immunized with a cocktail of SOSIP trimer and FP conjugate, and ∼30% in animals primed with FP conjugates before trimer immunization. Notably, neutralization breadth in FP-conjugate-primed animals correlates inversely with trimer-base responses. Our data provide methods to quantify the prevalence of trimer-base responses and reveal that FP-conjugate priming, either alone or as part of a cocktail, can reduce the trimer-base response and improve the neutralization outcome.
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•Devise methods to quantify antibody responses targeting the base of HIV-1 Env trimers•Fusion-peptide (FP) priming reduces anti-base responses upon HIV Env trimer boost•Lower percentage of anti-base responses correlates with improved neutralization breadth
The exposed base region of soluble HIV-1 Env trimers elicits strong non-neutralizing antibody responses. Corrigan et al. quantify plasma anti-base responses in immunized NHPs and observe a reduction in anti-base responses with fusion-peptide priming. The percentage of anti-base responses correlates inversely with neutralization breadth, providing insights for improving vaccination strategies.
HIV-1 envelope (Env) trimers, stabilized in a prefusion-closed conformation, can elicit humoral responses capable of neutralizing HIV-1 strains closely matched in sequence to the immunizing strain. ...One strategy to increase elicited neutralization breadth involves vaccine priming of immune responses against a target site of vulnerability, followed by vaccine boosting of these responses with prefusion-closed Env trimers. This strategy has succeeded at the fusion peptide (FP) site of vulnerability in eliciting cross-clade neutralizing responses in standard vaccine-test animals. However, the breadth and potency of the elicited responses have been less than optimal. Here, we identify three mutations (3mut), Met302, Leu320, and Pro329, that stabilize the apex of the Env trimer in a prefusion-closed conformation and show antigenically, structurally, and immunogenically that combining 3mut with other approaches (e.g., repair and stabilize and glycine-helix breaking) yields well-behaved clade C-Env trimers capable of boosting the breadth of FP-directed responses. Crystal structures of these trimers confirmed prefusion-closed apexes stabilized by hydrophobic patches contributed by Met302 and Leu320, with Pro329 assuming canonically restricted dihedral angles. We substituted the N-terminal eight residues of FP (FP8, residues 512 to 519) of these trimers with the second most prevalent FP8 sequence (FP8v2, AVGLGAVF) and observed a 3mut-stabilized consensus clade C-Env trimer with FP8v2 to boost the breadth elicited in guinea pigs of FP-directed responses induced by immunogens containing the most prevalent FP8 sequence (FP8v1, AVGIGAVF). Overall, 3mut can stabilize the Env trimer apex, and the resultant apex-stabilized Env trimers can be used to expand the neutralization breadth elicited against the FP site of vulnerability.
A major hurdle to the development of an effective HIV-1 vaccine is the elicitation of serum responses capable of neutralizing circulating strains of HIV, which are extraordinarily diverse in sequence and often highly neutralization resistant. Recently, we showed how sera with 20 to 30% neutralization breadth could, nevertheless, be elicited in standard vaccine test animals by priming with the most prevalent N-terminal 8 residues of the HIV-1 fusion peptide (FP8), followed by boosting with a stabilized BG505-envelope (Env) trimer. Here, we show that subsequent boosting with a 3mut-apex-stabilized consensus C-Env trimer, modified to have the second most prevalent FP8 sequence, elicits higher neutralization breadth than that induced by continued boosting with the stabilized BG505-Env trimer. With increased neutralizing breadth elicited by boosting with a heterologous trimer containing the second most prevalent FP8 sequence, the fusion peptide-directed immune-focusing approach moves a step closer toward realizing an effective HIV-1 vaccine regimen.
Conjugate-vaccine immunogens require three components: a carrier protein, an antigen, and a crosslinker, capable of coupling antigen to carrier protein, while preserving both T-cell responses from ...carrier protein and B-cell responses from antigen. We previously showed that the N-terminal eight residues of the HIV-1 fusion peptide (FP8) as an antigen could prime for broad cross-clade neutralizing responses, that recombinant heavy chain of tetanus toxin (rTTHC) as a carrier protein provided optimal responses, and that choice of crosslinker could impact both antigenicity and immunogenicity. Here, we delve more deeply into the impact of varying the linker between FP8 and rTTHC. In specific, we assessed the physical properties, the antigenicity, and the immunogenicity of conjugates for crosslinkers ranging in spacer-arm length from 1.5 to 95.2 Å, with varying hydrophobicity and crosslinking-functional groups. Conjugates coupled with different degrees of multimerization and peptide-to-rTTHC stoichiometry, but all were well recognized by HIV-fusion-peptide-directed antibodies VRC34.01, VRC34.05, PGT151, and ACS202 except for the conjugate with the longest linker (24-PEGylated SMCC; SM(PEG)24), which had lower affinity for ACS202, as did the conjugate with the shortest linker (succinimidyl iodoacetate; SIA), which also had the lowest peptide-to-rTTHC stoichiometry. Murine immunizations testing seven FP8-rTTHC conjugates elicited fusion-peptide-directed antibody responses, with SIA- and SM(PEG)24-linked conjugates eliciting lower responses than the other five conjugates. After boosting with prefusion-closed envelope trimers from strains BG505 clade A and consensus clade C, trimer-directed antibody-binding responses were lower for the SIA-linked conjugate; elicited neutralizing responses were similar, however, though statistically lower for the SM(PEG)24-linked conjugate, when tested against a strain especially sensitive to fusion-peptide-directed responses. Overall, correlation analyses revealed the immunogenicity of FP8-rTTHC conjugates to be negatively impacted by hydrophilicity and extremes of length or low peptide-carrier stoichiometry, but robust to other linker parameters, with several commonly used crosslinkers yielding statistically indistinguishable serological results.
Soluble HIV-1-envelope (Env) trimers elicit immune responses that target their solvent-exposed protein bases, the result of removing these trimers from their native membrane-bound context. To assess ...whether glycosylation could limit these base responses, we introduced sequons encoding potential N-linked glycosylation sites (PNGSs) into base-proximal regions. Expression and antigenic analyses indicated trimers bearing six-introduced PNGSs to have reduced base recognition. Cryo-EM analysis revealed trimers with introduced PNGSs to be prone to disassembly and introduced PNGS to be disordered. Protein-base and glycan-base trimers induced reciprocally symmetric ELISA responses, in which only a small fraction of the antibody response to glycan-base trimers recognized protein-base trimers and vice versa. EM polyclonal epitope mapping revealed glycan-base trimers –even those that were stable biochemically– to elicit antibodies that recognized disassembled trimers. Introduced glycans can thus mask the protein base but their introduction may yield neo-epitopes that dominate the immune response.
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•Designed soluble Env trimers with introduced N-linked glycans to mask base•Glycan addition substantially reduced recognition by base-directed antibodies•Immunization with protein- or glycan-base Env induced reciprocally symmetric ELISAs•Antibodies elicited by glycan-base trimers disassembled nominally stable trimers
Molecular structure; Virology
Soluble ‘SOSIP’-stabilized HIV-1 envelope glycoprotein (Env) trimers elicit dominant antibody responses targeting their glycan-free base regions, potentially diminishing neutralizing responses. ...Previously, using a nonhuman primate model, we demonstrated that priming with fusion peptide (FP)-carrier conjugate immunogens followed by boosting with Env trimers reduced the anti-base response. Further, we demonstrated that longer immunization intervals further reduced anti-base responses and increased neutralization breadth. Here, we demonstrate that long trimer-boosting intervals, but not long FP immunization intervals, reduce the anti-base response. Additionally, we identify that FP priming before trimer immunization enhances antibody avidity to the Env trimer. We also establish that adjuvants Matrix M and Adjuplex further reduce anti-base responses and increase neutralizing titers. FP priming, long trimer-immunization interval, and an appropriate adjuvant can thus reduce anti-base antibody responses and improve Env-directed vaccine outcomes.
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•We identify factors that improve or impact Env-directed HIV-1-vaccine outcomes•Long Env trimer interval, but not long FP interval, reduces anti-base responses•FP priming prior to trimer immunization increases antibody avidity to trimer•Adjuvants impact anti-base and epitope-specific immune responses
Immune response; Virology; Immunology
Background: Previous studies, in which one time point was used, have shown that cells infiltrating skin biopsy specimens taken during allergen-induced late-phase responses (LPR) had a TH2-like ...(interleukin-4 IL-4 and IL-5 mRNA+) cytokine profile, whereas in delayed-type hypersensitivity (DTH) there was a predominant TH1-type pattern.
Objective: The study was designed to examine the kinetics of accumulation of inflammatory cells and cells expressing mRNA for TH2- or TH1-type cytokines in LPR and DTH elicited simultaneously in the same subjects.
Methods: Immunocytochemistry (alkaline phosphatase anti-alkaline phosphatase technique) and in situ hybridization were used to analyze skin biopsy specimens taken during allergen-induced LPR.
Results: In LPR elevated numbers of CD3+ and CD4+ cells, eosinophils, neutrophils, and IL-4 and IL-5 mRNA+ cells were detected as early as 1 hour after allergen challenge, with a peak at 6 hours, which was maintained for up to 96 hours. A small but significant delayed increase in macrophages, CD8+ and CD25+ cells, and IL-2 and Interferon-γ mRNA+ cells was also observed, but only at the 48-hour and 96-hour time points. In contrast, in DTH the numbers of CD3+, CD4+, and mRNA+ cells for IL-2 and interferon-γ were not elevated until 24 hours after challenge and peaked at 48 hours after injection. At 48 hours there was an additional small but significant increase in IL-4 and IL-5 mRNA+ cells. For both LPR and DTH the kinetics of the increases in inflammatory cells and cytokine mRNA-expressing cells paralleled the clinical response.
Conclusions: In LPR accumulation of T cells and granulocytes, together with cells expressing mRNA encoding for TH2-type cytokines, is relatively rapid (i.e., within 1 to 6 hours), whereas in DTH the T cell/macrophage infiltration and appearance of cells expressing TH1-type cytokines are not apparent until 24 to 48 hours. In LPR there is a TH1-type (or possibly TH0) component at 48 to 96 hours, and in DTH there is an additionalTH2/TH0 response.
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