Parasites and the ecology of fear: Nonconsumptive effects of ectoparasites on larvae reduce growth in simulated Drosophila populations.

Predators negatively affect prey outside of direct attack, and these nonconsumptive effects (NCEs) may cause over half the impacts of predators on prey populations. This "ecology of fear" framework has been extended to host-parasite interactions. The NCEs of parasites are thought to be small relative to those of predators. However, recent research shows ectoparasites exert NCEs on multiple life stages of Drosophila. In this study, we apply recent data to a matrix-based model of fly populations experiencing infection/consumption and NCEs from an ectoparasitic mite. We found the NCEs of parasites on larvae, which are not actively parasitized, decreased the size of simulated host populations. By contrast, the NCEs on adult flies increased population size through compensatory egg production. The negative NCEs on larvae outweighed the positive effects on adults to reduce population size. This study suggests that parasitic NCEs can suppress host populations independent of infection.

HIV-1 neutralizing antibodies in SHIV-infected macaques recapitulate structurally divergent modes of human V2 apex recognition with a single D gene.

Broadly neutralizing antibodies targeting the V2 apex of the HIV-1 envelope trimer are among the most common specificities elicited in HIV-1-infected humans and simian-human immunodeficiency virus (SHIV)-infected macaques. To gain insight into the prevalent induction of these antibodies, we isolated and characterized 11 V2 apex-directed neutralizing antibody lineages from SHIV-infected rhesus macaques. Remarkably, all SHIV-induced V2 apex lineages were derived from reading frame two of the rhesus DH3-15*01 gene. Cryo-EM structures of envelope trimers in complex with antibodies from nine rhesus lineages revealed modes of recognition that mimicked three canonical human V2 apex-recognition modes. Notably, amino acids encoded by DH3-15*01 played divergent structural roles, inserting into a hole at the trimer apex, H-bonding to an exposed strand, or forming part of a loop scaffold. Overall, we identify a DH3-15*01-signature for rhesus V2 apex broadly neutralizing antibodies and show that highly selected genetic elements can play multiple roles in antigen recognition. Highlights: Isolated 11 V2 apex-targeted HIV-neutralizing lineages from 10 SHIV-infected Indian-origin rhesus macaquesCryo-EM structures of Fab-Env complexes for nine rhesus lineages reveal modes of recognition that mimic three modes of human V2 apex antibody recognitionAll SHIV-elicited V2 apex lineages, including two others previously published, derive from the same DH3-15*01 gene utilizing reading frame twoThe DH3-15*01 gene in reading frame two provides a necessary, but not sufficient, signature for V2 apex-directed broadly neutralizing antibodiesStructural roles played by DH3-15*01-encoded amino acids differed substantially in different lineages, even for those with the same recognition modePropose that the anionic, aromatic, and extended character of DH3-15*01 in reading frame two provides a selective advantage for V2 apex recognition compared to B cells derived from other D genes in the naïve rhesus repertoireDemonstrate that highly selected genetic elements can play multiple roles in antigen recognition, providing a structural means to enhance recognition diversity.

Anti-idiotype isolation of a broad and potent influenza A virus-neutralizing human antibody.

The VH6-1 class of antibodies includes some of the broadest and most potent antibodies that neutralize influenza A virus. Here, we elicit and isolate anti-idiotype antibodies against germline versions of VH6-1 antibodies, use these to sort human leukocytes, and isolate a new VH6-1-class member, antibody L5A7, which potently neutralized diverse group 1 and group 2 influenza A strains. While its heavy chain derived from the canonical IGHV6-1 heavy chain gene used by the class, L5A7 utilized a light chain gene, IGKV1-9, which had not been previously observed in other VH6-1-class antibodies. The cryo-EM structure of L5A7 in complex with Indonesia 2005 hemagglutinin revealed a nearly identical binding mode to other VH6-1-class members. The structure of L5A7 bound to the isolating anti-idiotype antibody, 28H6E11, revealed a shared surface for binding anti-idiotype and hemagglutinin that included two critical L5A7 regions: an FG motif in the third heavy chain-complementary determining region (CDR H3) and the CDR L1 loop. Surprisingly, the chemistries of L5A7 interactions with hemagglutinin and with anti-idiotype were substantially different. Overall, we demonstrate anti-idiotype-based isolation of a broad and potent influenza A virus-neutralizing antibody, revealing that anti-idiotypic selection of antibodies can involve features other than chemical mimicry of the target antigen.

Patient preferences in the treatment of stage III/IV classic Hodgkin lymphoma: Results from the CONNECT cross-sectional survey.

We explored patient front-line treatment preferences in newly diagnosed stage III/IV classic Hodgkin lymphoma (cHL). The CONNECT patient survey, administered online from 30 December 2020 to 1 March 2021, examined preferences overall and by age at diagnosis in 182 adult patients diagnosed with stage III/IV cHL within the past 10 years in the United States. At diagnosis, patients' median age was 36 years; 66% of patients were younger (aged 16-41 years) and 34% older (aged 42-85 years). When asked about initial treatment goals, 74% of patients ranked cure as their first or second goal (86% younger vs. 52% older patients; p < 0.001). At diagnosis, 72% of patients preferred aggressive treatment, and 85% were willing to accept more short-term risks in exchange for a better-working therapy long term. For long-term risks, younger versus older patients were significantly more concerned about second cancers (p < 0.001) and fertility issues (p = 0.007), whereas older patients were more concerned about lung damage (p = 0.028) and infections (p < 0.001). Most patients (94%) reported having a caregiver at some point, but 99% of these patients retained some control of treatment decisions. Collectively, these survey results highlight patient treatment preferences and differences in treatment goals and long-term side effect concerns based on patient age.

Long trimer-immunization interval and appropriate adjuvant reduce immune responses to the soluble HIV-1-envelope trimer base.

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.

Physician frontline treatment preferences for stage III/IV classic Hodgkin lymphoma: the real-world US CONNECT study.

Aim: To understand US physicians' frontline (1L) treatment preferences/decision-making for stage III/IV classic Hodgkin lymphoma (cHL). Materials & methods: Medical oncologists and/or hematologists (≥2 years' practice experience) who treat adults with stage III/IV cHL were surveyed online (October-November 2020). Results: Participants (n = 301) most commonly considered trial efficacy/safety data and national guidelines when selecting 1L cHL treatments. Most physicians (91%) rated overall survival (OS) as the most essential attribute when selecting 1L treatment. Variability was seen among regimen selection for hypothetical newly diagnosed patients, with OS cited as the most common reason for regimen selection. Conclusion: While treatment selection varied based on patient characteristics, US physicians consistently cited OS as the top factor considered when selecting a 1L treatment for cHL.

Classic Hodgkin lymphoma (cHL) is a type of cancer that grows in lymph nodes. The researchers created a survey to assess how doctors in the USA choose medicine to treat patients who are newly diagnosed with an advanced stage of cHL (stage 3 or 4 out of 4 stages). We surveyed 301 doctors who treat patients with cHL. When choosing a medicine to treat cHL, most doctors said they consider results from research studies, how well the medicine works, information on the medicine's safety and recommendations in official guidelines. Most doctors said that overall survival (how long the patient survives after being diagnosed with cHL) is the most important outcome they consider when choosing a medicine to treat cHL. During the survey, doctors saw four unique patient profiles. These profiles differed in age, disease stage (how far along the cHL is) and other illnesses the patient has. While medicine choice was different across profiles, overall survival was still the reason for choosing each individual patient's medicine. These survey results show that doctors in the USA highly consider overall survival when choosing medicine for patients newly diagnosed with an advanced stage of cHL.

The impact of classic Hodgkin lymphoma on informal caregivers: results from the CONNECT cross-sectional survey.

PURPOSE: As part of the CONNECT study, we evaluated the caregiver role in treatment decision-making when caring for patients with classic Hodgkin lymphoma (cHL) in the USA. METHODS: The CONNECT caregiver survey was administered online December 2020-March 2021 to self-identified adult caregivers of cHL patients recruited from patient referrals and online panels. The caregiver's role in treatment decision-making, health-related quality of life (HRQoL, PROMIS-Global), and work impacts (WPAI:CG) were assessed. RESULTS: We surveyed 209 caregivers (58% women; median age 47 years; 54% employed; 53% spouse/partner); 69% of patients cared for were diagnosed with cHL in the past 1-2 years, with 48% having stage III/IV cHL and 29% in remission. More spouse/partner than other caregivers were involved in caregiving at symptom onset (61% vs 27%), whereas more other than spouse/partner caregivers began after first treatment (34% vs 5%). Cure, caregivers' top treatment goal (49%), was rated higher by spouse/partner than other caregivers (56% vs 42%). More spouse/partner than other caregivers were involved in treatment option discussions with physicians (52% vs 28%), were involved in patients' treatment decisions (54% vs 23%), and were aligned with patients' treatment goals (93% vs 79%). While caregivers reported HRQoL similar to that of the general population, nearly 30% of employed caregivers reported work impairment. CONCLUSION: Cure was caregivers' top treatment goal. Spouse/partner vs other caregivers were more involved, were involved earlier, and reported greater alignment with patient treatment goals and decision-making. Caregivers reported good HRQoL; however, caregiving impacted work productivity regardless of patient relationship.

Soluble prefusion-closed HIV-envelope trimers with glycan-covered bases.

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.

Self-assembling SARS-CoV-2 spike-HBsAg nanoparticles elicit potent and durable neutralizing antibody responses via genetic delivery.

While several COVID-19 vaccines have been in use, more effective and durable vaccines are needed to combat the ongoing COVID-19 pandemic. Here, we report highly immunogenic self-assembling SARS-CoV-2 spike-HBsAg nanoparticles displaying a six-proline-stabilized WA1 (wild type, WT) spike S6P on a HBsAg core. These S6P-HBsAgs bound diverse domain-specific SARS-CoV-2 monoclonal antibodies. In mice with and without a HBV pre-vaccination, DNA immunization with S6P-HBsAgs elicited significantly more potent and durable neutralizing antibody (nAb) responses against diverse SARS-CoV-2 strains than that of soluble S2P or S6P, or full-length S2P with its coding sequence matching mRNA-1273. The nAb responses elicited by S6P-HBsAgs persisted substantially longer than by soluble S2P or S6P and appeared to be enhanced by HBsAg pre-exposure. These data show that genetic delivery of SARS-CoV-2 S6P-HBsAg nanoparticles can elicit greater and more durable nAb responses than non-nanoparticle forms of stabilized spike. Our findings highlight the potential of S6P-HBsAgs as next generation genetic vaccine candidates against SARS-CoV-2.

HIV-1 neutralizing antibodies elicited in humans by a prefusion-stabilized envelope trimer form a reproducible class targeting fusion peptide.

Elicitation of antibodies that neutralize the tier-2 neutralization-resistant isolates that typify HIV-1 transmission has been a long-sought goal. Success with prefusion-stabilized envelope trimers eliciting autologous neutralizing antibodies has been reported in multiple vaccine-test species, though not in humans. To investigate elicitation of HIV-1 neutralizing antibodies in humans, here, we analyze B cells from a phase I clinical trial of the "DS-SOSIP"-stabilized envelope trimer from strain BG505, identifying two antibodies, N751-2C06.01 and N751-2C09.01 (named for donor-lineage.clone), that neutralize the autologous tier-2 strain, BG505. Though derived from distinct lineages, these antibodies form a reproducible antibody class that targets the HIV-1 fusion peptide. Both antibodies are highly strain specific, which we attribute to their partial recognition of a BG505-specific glycan hole and to their binding requirements for a few BG505-specific residues. Prefusion-stabilized envelope trimers can thus elicit autologous tier-2 neutralizing antibodies in humans, with initially identified neutralizing antibodies recognizing the fusion-peptide site of vulnerability.

Assessment of Bone Health Awareness and Education in Breast Cancer Patients with Bone Metastasis in the USA.

Bone metastases are common in advanced breast cancer (BC) patients and increase the risk for skeletal-related events (SREs), which present a significant health and economic burden. Bone targeting agents (BTAs) can improve health-related quality of life by delaying or preventing SREs; nevertheless, a significant portion of eligible BC patients are not receiving this therapy. A bone health education needs assessment survey was conducted to examine cancer-related bone health awareness and to identify opportunities to improve bone health education. Direct-to-patient outreach was used to recruit adult BC patients in the USA self-reporting a diagnosis of bone metastasis within the past 3 years. Of the 200 patients, 59% experienced at least one SRE prior to survey participation (44% radiation to bone, 29% bone fracture, 17% spinal cord compression, 15% surgery to bone), and 83% were currently receiving a BTA. Awareness of general cancer bone health, protection strategies against SREs, and screening tests were low to moderate. Patients currently not receiving a BTA were least knowledgeable about cancer bone health, with only 40% aware of BTAs as a protective strategy, and only 26% were very or extremely satisfied with the information received from healthcare providers. Sixty-two percent of patients wanted to receive information by more than one mode of communication. Notable gaps in bone health education were observed in bone metastatic BC patients at risk for SREs, suggesting the need for earlier and more effective communication and education strategies to promote appropriate BTA use and better health outcomes.

An influenza H1 hemagglutinin stem-only immunogen elicits a broadly cross-reactive B cell response in humans.

Current yearly seasonal influenza vaccines primarily induce an antibody response directed against the immunodominant but continually diversifying hemagglutinin (HA) head region. These antibody responses provide protection against the vaccinating strain but little cross-protection against other influenza strains or subtypes. To focus the immune response on subdominant but more conserved epitopes on the HA stem that might protect against a broad range of influenza strains, we developed a stabilized H1 stem immunogen lacking the immunodominant head displayed on a ferritin nanoparticle (H1ssF). Here, we evaluated the B cell response to H1ssF in healthy adults ages 18 to 70 in a phase 1 clinical trial (NCT03814720). We observed both a strong plasmablast response and sustained elicitation of cross-reactive HA stem-specific memory B cells after vaccination with H1ssF in individuals of all ages. The B cell response was focused on two conserved epitopes on the H1 stem, with a highly restricted immunoglobulin repertoire unique to each epitope. On average, two-thirds of the B cell and serological antibody response recognized a central epitope on the H1 stem and exhibited broad neutralization across group 1 influenza virus subtypes. The remaining third recognized an epitope near the viral membrane anchor and was largely limited to H1 strains. Together, we demonstrate that an H1 HA immunogen lacking the immunodominant HA head produces a robust and broadly neutralizing HA stem-directed B cell response.

Observations of Oncologists on Treatment Selection With Interim Positron Emission Tomography-Adapted Approaches in Classic Hodgkin Lymphoma: The Real-World CONNECT Study.

PURPOSE: We surveyed oncologists who treat classic Hodgkin lymphoma (cHL) as part of the CONNECT study to understand the treatment decision-making process, including the impact of positron emission tomography/computed tomography (PET/CT) imaging. METHODS: US physicians self-identifying as oncologists, hematologists, or hematologists/oncologists with ≥2 years of practice experience who treated ≥1 adult with stage III/IV cHL in the frontline setting in the last year were surveyed (October 19-November 16, 2020). Physician demographics, guideline adherence, and PET/CT utilization, interpretation, and access barriers were assessed. RESULTS: In total, 301 physicians participated in the survey. Eighty-eight percent of physicians gave somewhat-to-significant consideration to NCCN guidelines. Most physicians (94%; n = 284) reported obtaining a PET/CT scan at diagnosis; of these physicians, 97% reported obtaining an interim PET/CT scan for stage III/IV cHL, with 65% typically obtaining an interim PET/CT scan after cycle 2. The Deauville 5-point scale (5PS) was the primary scoring system used to review PET/CT results by 62% of physicians, with a positive score defined as ≥3 by 44%, ≥4 by 37%, and ≥2 by 12% of physicians. Fifty-five percent of physicians reported difficulty in obtaining PET/CT scans. CONCLUSION: Although most physicians considered NCCN guidelines when treating patients with stage III/IV cHL, interim PET/CT scans after cycle 2 were not universally obtained. When PET/CT scans were obtained, Deauville 5PS scores were not always provided, and variability existed on what defined a positive score. These findings suggest that opportunities exist for education and improved PET-adapted treatment approaches.

Dual task cost in adults with persistent concussion symptoms.

BACKGROUND: Persistent concussion symptoms (PCS) negatively affects common activities of daily living including deficits in both single and dual-task (DT) gait. DT gait deficits are present post-concussion; however, task prioritization and the effects of differing cognitive challenge remain unexplored in the PCS population. RESEARCH QUESTION: The purpose of this study was to investigate single and dual-task gait performance in individuals with persistent concussion symptoms and to identify task priorization strategies during DT trials. METHODS: Fifteen adults with PCS (age: 43.9+11.7 y.o.) and 23 healthy control participants (age: 42.1+10.3 y.o.) completed five trials of single task gait followed by fifteen trials of dual task gait along a 10-m walkway. The cognitive challenges consisted of five trials each of visual stroop, verbal fluency, and working memory cognitive challenges. Groups were compared on DT cost stepping characteristics with independent samples t-test or Mann-Whitney U tests. RESULTS: There were significant overall gait Dual Task Cost (DTC)difference between groups for gait speed (p = 0.009, d=0.92) and step length (p = 0.023, d=0.76). Specific to each DT challenge, PCS participants were slower during Verbal Fluency (0.98 + 0.15 m/s and 1.12 + 0.12 m/s, p = 0.008; d=1.03), Visual Stroop (1.06 + 0.19 m/s and 1.20 + 0.12 m/s, p = 0.012, d=0.88), and Working Memory (1.02 + 0.15 m/s and 1.16 + 0.14 m/s, p = 0.006, d=0.96). There were significant cognitive DTC differences between groups for WM accuracy (p = 0.008, d=0.96), but not for VS accuracy (p = 0.841, d=0.061) or VF total words (p = 0.112, d=0.56). SIGNIFICANCE: The PCS participants displayed a posture-second strategy whereby gait performance generally decreased in the absence of cognitive changes. However, during the Working Memory DT, PCS participants had a mutual interference response whereby both motor and cognitive performance decreased suggesting the cognitive task plays a key role in the DT gait performance of PCS patients.

A potent and broad neutralization of SARS-CoV-2 variants of concern by DARPins.

We report the engineering and selection of two synthetic proteins-FSR16m and FSR22-for the possible treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. FSR16m and FSR22 are trimeric proteins composed of DARPin SR16m or SR22 fused with a T4 foldon. Despite selection by a spike protein from a now historical SARS-CoV-2 strain, FSR16m and FSR22 exhibit broad-spectrum neutralization of SARS-CoV-2 strains, inhibiting authentic B.1.351, B.1.617.2 and BA.1.1 viruses, with respective IC50 values of 3.4, 2.2 and 7.4 ng ml-1 for FSR16m. Cryo-EM structures revealed that these DARPins recognize a region of the receptor-binding domain (residues 456, 475, 486, 487 and 489) overlapping a critical portion of the angiotensin-converting enzyme 2 (ACE2)-binding surface. K18-hACE2 transgenic mice inoculated with B.1.617.2 and receiving intranasally administered FSR16m showed less weight loss and 10-100-fold lower viral burden in upper and lower respiratory tracts. The strong and broad neutralization potency makes FSR16m and FSR22 promising candidates for the prevention and treatment of infection by SARS-CoV-2.

A Physiological-Based Pharmacokinetic Model Embedded with a Target-Mediated Drug Disposition Mechanism Can Characterize Single-Dose Warfarin Pharmacokinetic Profiles in Subjects with Various CYP2C9 Genotypes under Different Cotreatments.

Warfarin, a commonly prescribed oral anticoagulant medication, is highly effective in treating deep vein thrombosis and pulmonary embolism. However, the clinical dosing of warfarin is complicated by high interindividual variability in drug exposure and response and its narrow therapeutic index. CYP2C9 genetic polymorphism and drug-drug interactions (DDIs) are substantial contributors to this high variability of warfarin pharmacokinetics (PK), among numerous factors. Building a physiology-based pharmacokinetic (PBPK) model for warfarin is not only critical for a mechanistic characterization of warfarin PK but also useful for investigating the complicated dose-exposure relationship of warfarin. Thus, the objective of this study was to develop a PBPK model for warfarin that integrates information regarding CYP2C9 genetic polymorphisms and their impact on DDIs. Generic PBPK models for both S- and R-warfarin, the two enantiomers of warfarin, were constructed in R with the mrgsolve package. As expected, a generic PBPK model structure did not adequately characterize the warfarin PK profile collected up to 15 days following the administration of a single oral dose of warfarin, especially for S-warfarin. However, following the integration of an empirical target-mediated drug disposition (TMDD) component, the PBPK-TMDD model well characterized the PK profiles collected for both S- and R-warfarin in subjects with different CYP2C9 genotypes. Following the integration of enzyme inhibition and induction effects, the PBPK-TMDD model also characterized the PK profiles of both S- and R-warfarin in various DDI settings. The developed mathematic framework may be useful in building algorithms to better inform the clinical dosing of warfarin. SIGNIFICANCE STATEMENT: The present study found that a traditional physiology-based pharmacokinetic (PBPK) model cannot sufficiently characterize the pharmacokinetic profiles of warfarin enantiomers when warfarin is administered as a single dose, but a PBPK model with a target-mediated drug disposition mechanism can. After incorporating CYP2C9 genotypes and drug-drug interaction information, the developed model is anticipated to facilitate the understanding of warfarin disposition in subjects with different CYP2C9 genotypes in the absence and presence of both cytochrome P450 inhibitors and cytochrome P450 inducers.

Development of a potential PET probe for HDAC6 imaging in Alzheimer's disease.

Although the epigenetic regulatory protein histone deacetylase 6 (HDAC6) has been recently implicated in the etiology of Alzheimer's disease (AD), little is known about the role of HDAC6 in the etiopathogenesis of AD and whether HDAC6 can be a potential therapeutic target for AD. Here, we performed positron emission tomography (PET) imaging in combination with histopathological analysis to better understand the underlying pathomechanisms of HDAC6 in AD. We first developed [18F]PB118 which was demonstrated as a valid HDAC6 radioligand with excellent brain penetration and high specificity to HDAC6. PET studies of [18F]PB118 in 5xFAD mice showed significantly increased radioactivity in the brain compared to WT animals, with more pronounced changes identified in the cortex and hippocampus. The translatability of this radiotracer for AD in a potential human use was supported by additional studies, including similar uptake profiles in non-human primates, an increase of HDAC6 in AD-related human postmortem hippocampal tissues by Western blotting protein analysis, and our ex vivo histopathological analysis of HDAC6 in postmortem brain tissues of our animals. Collectively, our findings show that HDAC6 may lead to AD by mechanisms that tend to affect brain regions particularly susceptible to AD through an association with amyloid pathology.

Relative contributions of parasite consumptive and non-consumptive effects to host population suppression in simulated fly-mite populations.

The "ecology of fear" framework was developed to describe the impacts predators have on potential prey and prey populations, outside of consumption/predation (i.e. non-consumptive effects, NCEs). This framework has recently been extended to symbiotic interactions such as host-parasite associations. Although the NCEs of predators and parasites on their individual victims can be measured experimentally, it is currently not known whether parasites can exert population-level effects on potential hosts through their NCEs. Modelling can be a useful tool for scaling individual-level NCEs to populations to determine impacts on host population growth. In this study, we used previously published data on the consumptive and non-consumptive effects of an ectoparasitic mite (Macrocheles subbadius) on a fruit fly (Drosophila nigrospiracula) to simulate populations experiencing fear (NCEs only), both fear and infection (consumption + NCEs) or neither. Population-level models indicate that NCEs alone were insufficient to reduce population growth. In fact, host populations experiencing NCEs but not infection had slightly larger final populations than unexposed populations (by ~ 550 flies). This result suggests there is compensation (i.e. increased daily reproduction that overcomes shorter lifespans) among exposed flies. By contrast, the consumptive effects of parasites suppressed the growth of simulated host populations, and this deleterious impact grew non-linearly with infection prevalence.

A multispecific antibody prevents immune escape and confers pan-SARS-CoV-2 neutralization.

Despite effective countermeasures, SARS-CoV-2 persists worldwide due to its ability to diversify and evade human immunity1. This evasion stems from amino-acid substitutions, particularly in the receptor-binding domain of the spike, that confer resistance to vaccines and antibodies 2-16. To constrain viral escape through resistance mutations, we combined antibody variable regions that recognize different receptor binding domain (RBD) sites17,18 into multispecific antibodies. Here, we describe multispecific antibodies, including a trispecific that prevented virus escape >3000-fold more potently than the most effective clinical antibody or mixtures of the parental antibodies. Despite being generated before the evolution of Omicron, this trispecific antibody potently neutralized all previous variants of concern and major Omicron variants, including the most recent BA.4/BA.5 strains at nanomolar concentrations. Negative stain electron microscopy revealed that synergistic neutralization was achieved by engaging different epitopes in specific orientations that facilitated inter-spike binding. An optimized trispecific antibody also protected Syrian hamsters against Omicron variants BA.1, BA.2 and BA.5, each of which uses different amino acid substitutions to mediate escape from therapeutic antibodies. Such multispecific antibodies decrease the likelihood of SARS-CoV-2 escape, simplify treatment, and maximize coverage, providing a strategy for universal antibody therapies that could help eliminate pandemic spread for this and other pathogens.

Pharmacokinetic Modeling of Warfarin ІI - Model-based Analysis of Warfarin Metabolites following Warfarin Administered either Alone or Together with Fluconazole or Rifampin.

The objective of this study is to conduct a population pharmacokinetic (PK) model-based analysis on 10 warfarin metabolites (4'-, 6-, 7-, 8- and 10-hydroxylated (OH)-S- and R- warfarin), when warfarin is administered alone or together with either fluconazole or rifampin. One or two compartment PK models expanded from target mediated drug disposition (TMDD) models developed previously for warfarin enantiomers were able to sufficiently characterize the PK profiles of 10 warfarin metabolites in plasma and urine under different conditions. Model-based analysis shows CYP2C9 mediated metabolic elimination pathways are more inhibitable by fluconazole (% formation CL (CLf) of 6- and 7-OH-S-warfarin decrease: 73.2% and 74.8%) but less inducible by rifampin (% CLf of 6- and 7-OH-S-warfarin increase: 85% and 75%), compared with non-CYP2C9 mediated elimination pathways (% CLf of 10-OH-S-warfarin and CLR of S-warfarin decrease in the presence of fluconazole: 65.0% and 15.3%; % CLf of 4'- 8- and 10-OH-S-warfarin increase in the presence of rifampin: 260%, 127% and 355%), which potentially explains the CYP2C9 genotype-dependent DDIs exhibited by S-warfarin, when warfarin is administrated together with fluconazole or rifampin. Additionally, for subjects with CYP2C9 *2 and *3 variants, a model-based analysis of warfarin metabolite profiles in subjects with various CYP2C9 genotypes demonstrates CYP2C9 mediated elimination is less important and non-CYP2C9 mediated elimination is more important, compared with subjects without these variants. To our knowledge, this is so far one of the most comprehensive population-based PK analyses of warfarin metabolites in subjects with various CYP2C9 genotypes under different co-medications. Significance Statement The studies we wish to publish are potentially impactful. The need for a TMDD pharmacokinetic model and the demonstration of genotyped-dependent drug interactions may explain the extensive variability in dose-response relationships that are seen in the clinical dose adjustments of warfarin.