Practical Applications of a Nausea and Vomiting Model in the Clinical Development of Additional Doses of Dulaglutide

Dulaglutide 3.0 and 4.5 mg weekly doses were approved for additional glycemic control in adult patients with type 2 diabetes inadequately controlled with metformin and 0.75 or 1.5 mg weekly doses of dulaglutide. Effects such as nausea and vomiting are commonly reported with dulaglutide and other glucagon-like peptide-1 receptor agonist therapies. Based on a pharmacokinetic/pharmacodynamic model-informed approach, a stepwise dose-escalation scheme with 4-week intervals between dose increments was suggested to mitigate gastrointestinal events for dulaglutide. These gastrointestinal events are dose dependent and attenuate over time with repeated dosing. A Markov chain Monte Carlo pharmacokinetic/pharmacodynamic joint model was developed using AWARD-11 data (N = 1842) to optimize dulaglutide dose escalation to 3.0 and 4.5 mg to mitigate gastrointestinal events. Model simulations evaluated probabilities of nausea and vomiting events for various dosing scenarios in patients needing higher doses for additional glycemic control. The model indicated that patients may dose escalate from 1.5 to 3.0 mg, then 4.5 mg weekly after at least 4 weeks on each dose. No clinically meaningful differences in nausea or vomiting events were expected when patients escalated to 3.0 or 4.5 mg following initiation at 0.75 or 1.5 mg dulaglutide. Based on the findings of this model, a minimum 4-week duration at each dose before escalation was appropriate to reduce gastrointestinal events of dulaglutide, consistent with observed gastrointestinal events data from the AWARD-11 study and supporting the currently recommended dose-escalation regimen of dulaglutide doses of 3.0 and 4.5 mg for additional glycemic control.

Efficacy and safety outcomes of dulaglutide by baseline HbA1c: A post hoc analysis of the REWIND trial

AIM

To assess cardiovascular, glycaemic, weight and safety outcomes of long-term treatment with dulaglutide 1.5 mg compared with placebo in patients with a baseline HbA1c of less than 7% versus 7% or higher.

MATERIALS AND METHODS

Intention-to-treat analyses were performed on REWIND participants with a baseline HbA1c measurement, using Cox proportional hazards regression and mixed model for repeated measures. Subgroup analyses with factors for baseline HbA1c categories and their interaction with treatment group, as well as analyses within the HbA1c subgroups, were conducted. Additionally, sensitivity analyses were performed for baseline HbA1c subgroups of 6.5% or less and more than 6.5%.

RESULTS

Of the 9876 eligible participants, 3921 and 5955 had a baseline HbA1c of less than 7% and 7% or higher, respectively. Mean baseline HbA1c was 6.3% and 8.0% and the mean duration of diabetes was 9.0 and 11.6 years in the respective subgroups. The less than 7% subgroup was slightly older and less frequently insulin-treated. There was no evidence of a differential dulaglutide treatment effect on body mass index (BMI) reduction, cardiovascular or safety outcomes of interest between the baseline HbA1c subgroups. Treatment-by-baseline HbA1c group interaction was significant for HbA1c change from baseline (P < .001), with a greater reduction in the subgroup with higher baseline HbA1c values. Sensitivity analyses by baseline HbA1c subgroups of 6.5% or less and more than 6.5% showed similar results.

CONCLUSIONS

The reduced incidence of cardiovascular events, and the reduction in BMI in participants treated with once-weekly dulaglutide, were independent of the baseline HbA1c level. Conversely, participants with a higher baseline HbA1c level had greater reductions in HbA1c. Dulaglutide has a positive benefit-risk profile and can be considered in patients with comparatively well-controlled HbA1c levels seeking optimal metabolic control and cardiovascular benefits.

Budget impact of lasmiditan for the acute treatment of migraine in the United States

BACKGROUND: Three novel acute treatments for migraine-lasmiditan, ubrogepant, and rimegepant-were approved by the FDA in 2019 and 2020 for adults with migraine with and without aura. American Headache Society guidance recommends that these novel acute treatments be considered for patients who are contraindicated to or fail to respond or tolerate oral triptans, the current standard of acute care. OBJECTIVE: To estimate, from a US commercial plan perspective, the budget impact of adding lasmiditan as an option to a formulary that already includes ubrogepant and rimegepant. METHODS: Epidemiologic data were drawn from US Census data, the American Migraine Prevalence and Preventive study, and the first wave of the OVERCOME US survey, a web-based survey that included 21,000 patients with migraine. A model with a 3-year time horizon was built assuming that demand for the novel acute treatments would not vary based on whether lasmiditan is included in the formulary. The model examined a variety of populations, in particular beneficiaries with previous use of 1 or more oral triptans or contraindicated to triptans and beneficiaries with previous use of 2 or more oral triptans or contraindicated to triptans. Primary outcomes were the incremental differences in total cost and average cost per member per month (PMPM) between scenarios with and without lasmiditan. One-way sensitivity analyses with model parameters that were varied by plus or minus 15% were conducted to assess the effect of key parameters on the incremental total cost over 3 years. RESULTS: The addition of lasmiditan to a formulary that already includes ubrogepant and rimegepant resulted in a total savings of -$927,657 (-1.5% compared with the scenario without lasmiditan) over a 3-year time horizon in the population with previous history of using 1 or more oral triptans or contraindicated to a triptan. In the population with previous history of using 2 or more oral triptans or contraindicated, the addition of lasmiditan resulted in a total budget impact of -$466,518 (-1.3%) over a 3-year time horizon. Most of the cost savings was attributable to reductions in drug acquisition cost. Savings in total costs resulted in average incremental cost per PMPM of -0.03 and -$0.01, respectively. CONCLUSIONS: The addition of lasmiditan to the formulary as a novel acute treatment option for migraine alongside ubrogepant and rimegepant resulted in lower budget impact on a 3-year time horizon from a US commercial payer's perspective. This result is important to US commercial payers as they seek to incorporate the emerging novel acute treatments for migraine into their benefit designs. DISCLOSURES: This work was funded by Eli Lilly and Company. Milev and Sun are employed by Evidera, which received funding from Eli Lilly and Company for work on this project. Pohl, Mason, Njuguna, and Loo are employees and stockholders of Eli Lilly and Company.

A close association of freedom from pain, migraine-related functional disability, and other outcomes: results of a post hoc analysis of randomized lasmiditan studies SAMURAI and SPARTAN

BACKGROUND

While pain freedom at 2 h is a key primary outcome for current trials for acute treatment of migraine, the relationship between the degree of head pain and other efficacy measures at 2 h has rarely been explored. Following lasmiditan treatment of a migraine attack with moderate or severe head pain, we contrast those who achieve pain freedom with those who achieve mild pain but not pain freedom 2 h post dosing.

METHODS

Patient-level data were pooled across studies and treatment arms from two Phase 3 trials comparing lasmiditan and placebo, SAMURAI and SPARTAN. This post hoc analysis assessed freedom from the most bothersome symptom (MBS), freedom from migraine-related functional disability (disability), and improved patient global impression of change (PGIC) in patients who achieved 2 h pain freedom compared to those who experienced 2 h mild pain. Mild pain differs from pain relief which is defined as either mild pain or pain freedom.

RESULTS

Patients who achieved 2 h pain freedom (N = 913), in comparison with those with 2 h mild pain (N = 864), were significantly more likely to experience MBS freedom (91.9% vs. 44.9%), disability freedom (87.1% and 13.4%), and improved PGIC (86.5% and 31.5%) (p < 0.001 for all combinations). In addition, more patients who were pain free experienced both 2 h MBS freedom and 2 h functional disability freedom (83.6%) compared to those with mild pain (10.8%; p < 0.001). The proportion of patients with pain freedom who did not achieve either MBS or disability freedom (4.6%) was lower than in patients with mild pain (52.4%). Lastly, 55.2% of patients experienced mild pain before disability freedom compared to 72.1% who experienced pain freedom and disability freedom at the same time.

CONCLUSIONS

This study demonstrated that, at 2 h post treatment, patients who were pain free were more likely to achieve other outcomes including freedom from their MBS, freedom from migraine-related functional disability, and improved PGIC compared to those with mild pain, confirming that 2 h pain freedom is more robustly associated with other clinical outcomes than the 2 h mild pain endpoint.

TRIAL REGISTRATION

SAMURAI ( NCT02439320 ); SPARTAN ( NCT02605174 ).

Evaluation of Patients with Insufficient Efficacy and/or Tolerability to Triptans for the Acute Treatment of Migraine: A Systematic Literature Review

INTRODUCTION

Use of triptans for acute treatment of migraine is associated with insufficient efficacy and/or tolerability in approximately 30-40% of people. We conducted a systematic literature review (SLR) to synthesize definitions, terminology, subsequent treatment outcomes, and characteristics associated with this subpopulation.

METHODS

A comprehensive SLR was conducted to identify studies, published from Jan 1995 to May 2019, which focused on insufficient efficacy and/or tolerability to triptans.

RESULTS

Thirty-five publications were identified, of which 22 described randomized controlled trials and open-label studies, and 13 described observational studies. Across studies, multiple objectives and a high amount of variability in methodologies and outcomes were noted. The most commonly applied measures of efficacy were headache pain freedom and pain relief at 2 h. Ten studies assessed efficacy of switching or optimizing treatment in patients with historical insufficient efficacy or tolerability to previous triptan treatment and demonstrated varying levels of success. Factors associated with increased risk of triptan insufficient efficacy included severe baseline headache severity, photophobia, phonophobia, nausea, and depression.

CONCLUSIONS

Irrespective of the methodology or definition used to identify people with insufficient efficacy and/or tolerability to triptans, study results support the assertion that a high unmet need remains for effective acute treatment of migraine.

Trajectory of migraine-related disability following long-term treatment with lasmiditan: results of the GLADIATOR study

BACKGROUND

Migraine is recognized as the second leading cause of disability globally. Lasmiditan is a novel, selective serotonin 5-HT1F receptor agonist developed for acute treatment of migraine. Here we analyzed effects of lasmiditan on migraine disability assessed with the Migraine Disability Assessment (MIDAS) scale for interim data from a long-term safety study.

METHODS

Completers of two single-attack parent studies were offered participation in the 1 year GLADIATOR study, that randomized participants to treatment with lasmiditan 100 mg or 200 mg taken as needed for migraine attacks of at least moderate severity. Changes in MIDAS were modeled using a mixed model repeated measures analysis.

RESULTS

The sample included 1978 patients who received ≥1 lasmiditan dose and were followed for a median of 288 days. Baseline mean MIDAS scores for the lasmiditan 100-mg and 200-mg groups were 29.4 and 28.9, respectively, indicating severe migraine-related disability. Relative to baseline, MIDAS total scores were significantly lower at 3, 6, 9, and 12 months for both dose groups. At 12 months, changes in MIDAS scores were - 12.5 and - 12.2 for lasmiditan 100 mg and 200 mg, respectively, with 49% and 53% of patients, respectively, achieving at least a 50% decrease in MIDAS total score. Statistically significant improvements were also seen for work and/or school absenteeism and presenteeism, monthly headache days, and mean headache pain intensity at all time points up to 1 year. Findings for patients who completed all visits versus those dropping out early were similar. Responses were generally similar for the lasmiditan 100 mg or 200 mg doses, between subgroups defined based on the number of baseline monthly migraine attacks (≤5 vs. >5), and also between subgroups defined by pain-free response (yes/no) during initial attacks.

CONCLUSIONS

Long-term treatment with lasmiditan was associated with significant reductions in migraine-related disability, including both work or school absenteeism and presenteeism. The similarity of responses in completers and those who dropped out suggests that selective attrition does not account for the improvements. Benefits were significant at 3 months and maintained through 12 months.

TRIAL REGISTRATION

clinicaltrials.govNCT02565186; first posted October 1, 2015.

Abuse Potential of Lasmiditan: A Phase 1 Randomized, Placebo- and Alprazolam-Controlled Crossover Study

Lasmiditan is a centrally penetrant, highly selective 5‐hydroxytryptamine (serotonin) receptor 1F (5HT_1F) agonist under development as a novel therapy for acute treatment of migraine. A phase 1 randomized, placebo‐ and positive‐controlled crossover study assessed the abuse potential of lasmiditan in adult recreational polydrug users. Following a qualification phase, subjects were randomized into treatment sequences, each consisting of 5 study treatments: placebo, alprazolam 2 mg, lasmiditan 100, 200 (lasmiditan 100 and 200 mg are proposed therapeutic doses), and 400 mg (supratherapeutic). The abuse potential of lasmiditan was investigated and compared with alprazolam and with placebo using the maximal effect score (E_max) of the Drug‐Liking Visual Analog Scale as the primary end point. Lasmiditan was not similar to placebo in drug‐liking scores at all doses tested, with a maximum difference observed with the lasmiditan 400‐mg dose (upper 90% confidence limit on difference in least‐squares [LS] means > 14 for all lasmiditan doses). Drug‐liking scores for lasmiditan 400 mg were not significantly different from alprazolam (lower 90% confidence limit on difference in LS means < 5), but drug‐liking scores at lower doses (100 and 200 mg) were significantly different from alprazolam. During the treatment phase, the incidence of treatment‐emergent adverse events (TEAEs) increased with increasing dose of lasmiditan; all TEAEs reported with lasmiditan treatment were mild. Subjective drug‐liking effects for lasmiditan versus placebo and versus alprazolam, and the safety and tolerability profile of lasmiditan suggest that lasmiditan has a low potential for abuse.

Lasmiditan for the acute treatment of migraine: Subgroup analyses by prior response to triptans

Background

Lasmiditan demonstrated superiority to placebo in the acute treatment of migraine in adults with moderate/severe migraine disability in two similarly designed Phase 3 trials, SAMURAI and SPARTAN. Post-hoc integrated analyses evaluated the efficacy of lasmiditan in patients who reported a good or insufficient response to triptans and in those who were triptan naïve.

Methods

Subgroups of patients reporting an overall response of “good” or “poor/none” to the most recent use of a triptan at baseline (defined as good or insufficient responders, respectively) and a triptan-naïve subpopulation were derived from combined study participants randomized to receive lasmiditan 50 mg (SPARTAN only), 100 mg or 200 mg, or placebo, as the first dose. Outcomes including headache pain-freedom, most bothersome symptom-freedom, and headache pain relief 2 hours post-first dose of lasmiditan were compared with placebo. Treatment-by-subgroup analyses additionally investigated whether therapeutic benefit varied according to prior triptan response (good or insufficient).

Results

Regardless of triptan response, lasmiditan showed higher efficacy than placebo (most comparisons were statistically significant). Treatment-by-subgroup analyses found that the benefit over placebo of lasmiditan did not vary significantly between patients with a good response and those with an insufficient response to triptans. Lasmiditan also showed higher efficacy than placebo in triptan-naïve patients.

Conclusions

Lasmiditan demonstrated comparable efficacy in patients who reported a good or insufficient response to prior triptan use. Lasmiditan also showed efficacy in those who were triptan naïve. Lasmiditan may be a useful therapeutic option for patients with migraine.

Trial Registration

SAMURAI (NCT02439320); SPARTAN (NCT02605174).

Effect of a rescue or recurrence dose of lasmiditan on efficacy and safety in the acute treatment of migraine: findings from the phase 3 trials (SAMURAI and SPARTAN)

Background

We studied the efficacy and safety of a second dose of lasmiditan for acute treatment of migraine.

Methods

SAMURAI and SPARTAN were double-blind, placebo-controlled Phase 3 studies in which individuals with migraine were randomized to oral lasmiditan 50 mg (SPARTAN only), 100 mg, 200 mg, or placebo. Study drug was to be taken within 4 h (h) of onset of a migraine attack (moderate or severe pain). A second dose of study drug was provided for rescue (patient not pain-free at 2 h and took a second dose 2-24 h post-first dose) or recurrence (patient pain-free at 2 h, but experienced recurrence of mild, moderate, or severe migraine pain and took a second dose 2-24 h after first dose). Randomization to second dose occurred at baseline; patients originally assigned lasmiditan were randomized to the same lasmiditan dose or placebo (2:1 ratio), and those originally assigned placebo received placebo. Data from SAMURAI and SPARTAN were pooled for efficacy and safety assessment of a second dose of lasmiditan.

Results

The proportion of patients taking a second dose was lower with lasmiditan versus placebo, and decreased with increasing lasmiditan dose; the majority who took a second dose did so for rescue. In patients taking lasmiditan as first dose, outcomes (pain free, most bothersome symptom [MBS] free) at 2 h after a second dose for rescue were similar whether the second dose was lasmiditan or placebo (p > 0.05 in all cases). In patients taking lasmiditan for first dose, outcomes at 2 h after a second dose for recurrence were as follows: lasmiditan pooled versus placebo - pain free, 50% vs 32% (p > 0.05); MBS free, 71% vs 41% (p = 0.02); pain relief, 77% vs 52% (p = 0.03). In patients whose first dose was lasmiditan, the incidence of treatment emergent adverse events (TEAEs) reported after the second dose was similar whether second dose was lasmiditan or placebo.

Conclusions

A second dose of lasmiditan showed some evidence of efficacy when taken for headache recurrence. There was no clear benefit of a second dose of lasmiditan for rescue treatment. The incidences of TEAEs were similar whether the second dose was lasmiditan or placebo.

Trial registration

SAMURAI (NCT02439320) [April 2015]. SPARTAN (NCT02605174) [May 2016].

Efficacy and safety of lasmiditan in patients using concomitant migraine preventive medications: findings from SAMURAI and SPARTAN, two randomized phase 3 trials

OBJECTIVE

To study the efficacy and safety of lasmiditan for acute treatment of migraine in patients using migraine preventive medications.

BACKGROUND

While lasmiditan has been proven to be an effective acute treatment for migraine, its effectiveness has not been examined when used concurrently with migraine preventives.

METHODS

SAMURAI and SPARTAN were similarly designed, double-blind, phase 3, placebo-controlled studies of patients 18 years or older with 3 to 8 migraine attacks per month. Patients were randomized to treat a migraine attack with oral lasmiditan 50 mg (SPARTAN only), 100 mg, 200 mg, or placebo. Migraine preventives were allowed as long as doses were stable for 3 months prior to screening and were unchanged during the study. Preventive medications with established or probable efficacy, as recommended by the American Academy of Neurology, the American Headache Society, and the European Headache Federation, plus botulinum toxin type A and candesartan, were included. Within the subgroups of patients using and not using preventive therapies, lasmiditan and placebo groups were analyzed for the outcome of pain-free at 2 h and other efficacy outcomes. The subgroups of patients using and not using preventive therapies were compared and interaction p-values were calculated for safety and efficacy outcomes.

RESULTS

In these trials, 698 of 3981 patients (17.5%) used migraine preventive treatments. Among patients using preventives, all lasmiditan doses resulted in significantly more patients being pain-free at 2 h, compared to placebo (p < 0.05). Primary efficacy outcome (pain-free at 2 h), key secondary outcome (most bothersome symptom-free at 2 h) and all other efficacy outcomes were not significantly different between patients using or not using migraine preventives (all interaction p-values ≥0.1). Rates of adverse events were similar for patients using and not using preventive medications.

CONCLUSIONS

Lasmiditan was more effective than placebo for the acute treatment of migraine in patients concurrently using migraine preventive medications. Lasmiditan efficacy and safety measures were similar for patients using and not using preventive medications.

TRIAL REGISTRATION

SAMURAI (NCT02439320) and SPARTAN (NCT02605174). Registered 18 March 2015.

A role for sorting nexin 27 in AMPA receptor trafficking

Sorting nexin 27 (SNX27), a PDZ domain-containing endosomal protein, was recently shown to modulate glutamate receptor recycling in Down's syndrome. However, the precise molecular role of SNX27 in GluA1 trafficking is unclear. Here we report that SNX27 is enriched in dendrites and spines, along with recycling endosomes. Significantly, the mobilization of SNX27 along with recycling endosomes into spines was observed. Mechanistically, SNX27 interacts with K-ras GTPase via the RA domain; and following chemical LTP stimuli, K-ras is recruited to SNX27-enriched endosomes through a Ca(2+)/CaM-dependent mechanism, which in turn drives the synaptic delivery of homomeric GluA1 receptors. Impairment of SNX27 prevents LTP and associated trafficking of AMPARs. These results demonstrate a role for SNX27 in neuronal plasticity, provide a molecular explanation for the K-ras signal during LTP and identify SNX27 as the PDZ-containing molecular linker that couples the plasticity stimuli to the delivery of postsynaptic cargo.

Sorting nexin 27 couples PTHR trafficking to retromer for signal regulation in osteoblasts during bone growth

The parathyroid hormone 1 receptor (PTHR) is central to the process of bone formation and remodeling. PTHR signaling requires receptor internalization into endosomes, which is then terminated by recycling or degradation. Here we show that sorting nexin 27 (SNX27) functions as an adaptor that couples PTHR to the retromer trafficking complex. SNX27 binds directly to the C-terminal PDZ-binding motif of PTHR, wiring it to retromer for endosomal sorting. The structure of SNX27 bound to the PTHR motif reveals a high-affinity interface involving conserved electrostatic interactions. Mechanistically, depletion of SNX27 or retromer augments intracellular PTHR signaling in endosomes. Osteoblasts genetically lacking SNX27 show similar disruptions in PTHR signaling and greatly reduced capacity for bone mineralization, contributing to profound skeletal deficits in SNX27-knockout mice. Taken together, our data support a critical role for SNX27-retromer mediated transport of PTHR in normal bone development.

An oncogenic role of Agrin in regulating focal adhesion integrity in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally. The identity and role of cell surface molecules driving complex biological events leading to HCC progression are poorly understood, hence representing major lacunae in HCC therapies. Here, combining SILAC quantitative proteomics and biochemical approaches, we uncover a critical oncogenic role of Agrin, which is overexpressed and secreted in HCC. Agrin enhances cellular proliferation, migration and oncogenic signalling. Mechanistically, Agrin’s extracellular matrix sensor activity provides oncogenic cues to regulate Arp2/3-dependent ruffling, invadopodia formation and epithelial–mesenchymal transition through sustained focal adhesion integrity that drives liver tumorigenesis. Furthermore, Agrin signalling through Lrp4-muscle-specific tyrosine kinase (MuSK) forms a critical oncogenic axis. Importantly, antibodies targeting Agrin reduced oncogenic signalling and tumour growth in vivo. Together, we demonstrate that Agrin is frequently upregulated and important for oncogenic property of HCC, and is an attractive target for antibody therapy.

The proteoglycan Agrin is known to be expressed in neurons and muscle and to bind ECM protein laminin. Here the authors report that Agrin promotes hepatocellular carcinoma by stimulating proliferation, decreasing focal adhesion, increasing invasiveness and promoting an epithelial-to-mesenchymal transition.

Loss of sorting nexin 27 contributes to excitatory synaptic dysfunction by modulating glutamate receptor recycling in Down's syndrome

Sorting nexin 27 (SNX27), a brain-enriched PDZ domain protein, regulates endocytic sorting and trafficking. Here we show that Snx27(-/-) mice have severe neuronal deficits in the hippocampus and cortex. Although Snx27(+/-) mice have grossly normal neuroanatomy, we found defects in synaptic function, learning and memory and a reduction in the amounts of ionotropic glutamate receptors (NMDA and AMPA receptors) in these mice. SNX27 interacts with these receptors through its PDZ domain, regulating their recycling to the plasma membrane. We demonstrate a concomitant reduced expression of SNX27 and CCAAT/enhancer binding protein β (C/EBPβ) in Down's syndrome brains and identify C/EBPβ as a transcription factor for SNX27. Down's syndrome causes overexpression of miR-155, a chromosome 21-encoded microRNA that negatively regulates C/EBPβ, thereby reducing SNX27 expression and resulting in synaptic dysfunction. Upregulating SNX27 in the hippocampus of Down's syndrome mice rescues synaptic and cognitive deficits. Our identification of the role of SNX27 in synaptic function establishes a new molecular mechanism of Down's syndrome pathogenesis.

p125A exists as part of the mammalian Sec13/Sec31 COPII subcomplex to facilitate ER-Golgi transport

p125A is an accessory protein for COPII-mediated vesicle budding that links the Sec13/Sec31 and Sec23/24 subcomplexes.

Coat protein II (COPII)–mediated export from the endoplasmic reticulum (ER) involves sequential recruitment of COPII complex components, including the Sar1 GTPase, the Sec23/Sec24 subcomplex, and the Sec13/Sec31 subcomplex. p125A was originally identified as a Sec23A-interacting protein. Here we demonstrate that p125A also interacts with the C-terminal region of Sec31A. The Sec31A-interacting domain of p125A is between residues 260–600, and is therefore a distinct domain from that required for interaction with Sec23A. Gel filtration and immunodepletion studies suggest that the majority of cytosolic p125A exists as a ternary complex with the Sec13/Sec31A subcomplex, suggesting that Sec 13, Sec31A, and p125A exist in the cytosol primarily as preassembled Sec13/Sec31A/p125A heterohexamers. Golgi morphology and protein export from the ER were affected in p125A-silenced cells. Our results suggest that p125A is part of the Sec13/Sec31A subcomplex and facilitates ER export in mammalian cells.

A role for endobrevin/VAMP8 in CTL lytic granule exocytosis

CTL clear virus-infected cells and tumorigenic cells by releasing potent cytotoxic enzymes stored in preformed lytic granules. The exocytosis process includes polarization of lytic granules toward the immunological synapse, tethering of lytic granules to the plasma membrane and finally fusion of lytic granules with the plasma membrane to release cytotoxic enzymes. Although much is known about the molecular machineries necessary for the earlier steps in lytic granule exocytosis, the molecular machinery governing the final step in the fusion process has not been identified. Here, we show using control and VAMP8 KO mice that VAMP8 is localized to the CTL lytic granules. While the immunological synapse and granule polarization appears normal in both VAMP8 KO and control CTL, CTL-mediated killing was reduced for the Vamp8(-/-) CTL. Analysis of lytic enzyme secretion demonstrated that granzyme A and granzyme B secretion is significantly compromised in VAMP8(-/-) CTL, while the levels of the lytic enzymes in the cells are unaffected. Our results clearly show that VAMP8 is one of the v-SNARE that regulate the lytic ability of CTL by influencing the ability of the lytic granules to fuse with the plasma membrane and release its contents.

Participation of Tom1L1 in EGF-stimulated endocytosis of EGF receptor

Although many proteins have been shown to participate in ligand-stimulated endocytosis of EGF receptor (EGFR), the adaptor protein responsible for interaction of activated EGFR with endocytic machinery remains elusive. We show here that EGF stimulates transient tyrosine phosphorylation of Tom1L1 by the Src family kinases, resulting in transient interaction of Tom1L1 with the activated EGFR bridged by Grb2 and Shc. Cytosolic Tom1L1 is recruited onto the plasma membrane and subsequently redistributes into the early endosome. Mutant forms of Tom1L1 defective in Tyr-phosphorylation or interaction with Grb2 are incapable of interaction with EGFR. These mutants behave as dominant-negative mutants to inhibit endocytosis of EGFR. RNAi-mediated knockdown of Tom1L1 inhibits endocytosis of EGFR. The C-terminal tail of Tom1L1 contains a novel clathrin-interacting motif responsible for interaction with the C-terminal region of clathrin heavy chain, which is important for exogenous Tom1L1 to rescue endocytosis of EGFR in Tom1L1 knocked-down cells. These results suggest that EGF triggers a transient Grb2/Shc-mediated association of EGFR with Tyr-phosphorylated Tom1L1 to engage the endocytic machinery for endocytosis of the ligand-receptor complex.

TEADs mediate nuclear retention of TAZ to promote oncogenic transformation

The transcriptional coactivators YAP and TAZ are downstream targets inhibited by the Hippo tumor suppressor pathway. The expression level of TAZ is recently shown to be elevated in invasive breast cancer cells and some primary breast cancers. TAZ is important for breast cancer cell migration, invasion, and tumorigenesis, but the underlying mechanism is not defined. In this study, we show that TAZ interacts with TEAD transcriptional factors. Knockdown of TEADs suppresses TAZ-mediated oncogenic transformation of MCF10A cells. Uncoupling TAZ from Hippo regulation by S89A mutation enhances its transforming ability. Several residues located in the N-terminal region of TAZ are identified to be important for interaction with TEADs, and these same residues are equally important for TAZ to transform MCF10A cells. Mechanistically, TAZ mutants defective in interaction with TEADs fail to accumulate in the nucleus. Live cell imaging of enhanced green fluorescent protein-TAZ and its mutant defective in TEAD interaction suggests that TEAD interaction mediates nuclear retention. These results reveal a novel mechanism for TEADs to regulate nuclear retention and thus the transforming ability of TAZ.

Impaired volume regulation is the mechanism of excitotoxic sensitization to complement

Previous work demonstrated that a brief, sublethal excitotoxic insult strikingly increased the sensitivity of cortical neurons to the cytotoxic effects of the terminal pathway of complement, a process termed "excitotoxic sensitization." Here, we sought to elucidate the cellular mechanism of excitotoxic sensitization in embryonic rat cortical neurons in vitro. Excitotoxic sensitization did not increase membrane attack complex deposition on cortical neurons and produced only a small reduction of membrane attack complex removal, because of a selective decrease of endocytic elimination. Membrane attack complexes and other osmotic stressors, namely hypotonic stress and glutamate, induced transient swelling of cortical neurons, followed by return to normal volume despite persistence of the stressor, a homeostatic response termed regulatory volume decrease (RVD). A minimal excitotoxic insult impaired this homeostatic response and sensitized neurons to cytotoxic effects of diverse osmotic stressors. Structurally distinct membrane-impermeable osmolytes, dextran and polyethylene glycol, prevented excitotoxic sensitization to diverse osmotic stressors including membrane attack complexes. Paraquat, a reactive oxygen species generator, alone was sufficient to impair RVD, and MnTBAP [Mn(III)tetrakis(4-benzoic acid)porphyrin chloride], a reactive oxygen species scavenger, prevented excitotoxin-mediated impairment of RVD. Together, these findings demonstrate that impairment of RVD is the mechanism of excitotoxic sensitization, that reactive oxygen species alone are sufficient to impair RVD, and that reactive oxygen species are necessary for excitotoxic sensitization-mediated impairment of RVD.

Chain mobility in the amorphous region of nylon 6 observed under active uniaxial deformation

A specially designed solid-state deuterium nuclear magnetic resonance probe was used to examine the effect of uniaxial elongation on the chain mobility in the amorphous region of semicrystalline nylon 6. In measurements conducted near the glass transition temperature, there was measurable deformation-induced enhancement of the mobility of the amorphous chains up to the yield point. This enhanced mobility decayed once deformation was stopped. Enhanced mobility was not observed in deformation at room temperature. The mechanics of deformation can be explained by the Robertson model for glassy polymers near the glass transition temperature, which states that applied stress induces liquid-like behavior in the polymer chains.

DNA methylation patterns of the gamma delta beta-globin genes in human fetal and adult erythroid tissues

An investigation of the correlation between the gamma----beta-globin switch and DNA methylation was carried out. The restriction patterns obtained with methylation-sensitive and -insensitive enzymes indicated hypomethylation in the promoter region of the gamma-globin genes in fetal liver DNA but high methylation of the same region in all other samples (except in the presence of an elevated erythroblast count or leukemia). All samples appeared to be partially hypomethylated at the 5' end of the delta-globin gene and hypomethylated at the 3' region of the beta-globin gene. Although consistent with a role for DNA methylation in globin gene regulation, the results also suggest that other factors besides methylation may be required for regulation of the level of expression, and switching of the globin genes.

Natural killer cell cytotoxicity to herpes simplex virus-1-infected cells is not altered by pregnancy

There is evidence to suggest a decrease in natural killer cell cytotoxicity during pregnancy, but information regarding immune responsiveness to actual infection is limited. An in vitro study was undertaken to examine the effect of herpes simplex virus infection on natural killer cell cytotoxicity with peripheral blood mononuclear cells from pregnant (N = 8) and nonpregnant (N = 5) women. The peripheral blood mononuclear cells were separated by Ficoll-Hypaque centrifugation. Effector cells were incubated with live herpes simplex virus-1, ultraviolet-inactivated herpes simplex virus-1, or media alone for 18 hours at 37 degrees C. K562 target cells were used in a sodium chromate release assay with an effector-to-target cell ratio of 100:1. Baseline natural killer cell values (mean +/- SE) for pregnant patients (13.4% +/- 2.4%) and nonpregnant patients (19.8% +/- 3.7%) were similar. Natural killer cell cytotoxicity was significantly increased by incubation with live virus for both pregnant (37.5% +/- 6.2%) and nonpregnant subjects (49.8% +/- 7.6%). There was no difference in mean values between media and ultraviolet-inactivated herpes simplex virus-1-exposed samples for either group. Results suggest that (1) infection with live virus, but not viral antigen alone, can augment natural killer cell response in vitro and (2) natural killer cell response to herpes simplex virus-1 infection is not altered by pregnancy.

Neonatal antibody-dependent cellular cytotoxic antibody levels are associated with the clinical presentation of neonatal herpes simplex virus infection

The role of antiviral antibodies in protection against neonatal herpes simplex virus (HSV) infection remains controversial. The relationship between neonatal and maternal anti-HSV antibodies and disease presentation was analyzed in 47 babies. Of the neonates, 77% had localized and 23% had disseminated HSV infection. Antibody-dependent cellular cytotoxic (ADCC) antibodies were evaluated in comparison with HSV neutralizing antibodies. High maternal (greater than 1:10(4)) or neonatal (greater than 1:10(3)) anti-HSV ADCC antibody levels or high neonatal antiviral neutralizing levels (greater than 1:20) were independently associated with an absence of disseminated HSV infection. Cochran-Mantel-Haenszel analysis demonstrated that ADCC levels were associated with disease status (P less than .02) while controlling for the level of neutralizing antibody.

Trimethoprim resistance transposon Tn4003 from Staphylococcus aureus encodes genes for a dihydrofolate reductase and thymidylate synthetase flanked by three copies of IS257

Trimethoprim resistance mediated by the Staphylococcus aureus multi-resistance plasmid pSK1 is encoded by a structure with characteristics of a composite transposon which we have designated Tn4003. Nucleotide sequence analysis of Tn4003 revealed it to be 4717 bp in length and to contain three copies of the insertion element IS257 (789-790 bp), the outside two of which are flanked by directly repeated 8-bp target sequences. IS257 has imperfect terminal inverted repeats of 27-28 bp and encodes for a putative transposase with two potential alpha-helix-turn-alpha-helix DNA recognition motifs. IS257 shares sequence similarities with members of the IS15 family of insertion sequences from Gram-negative bacteria and with ISS1 from Streptococcus lactis. The central region of the transposon contains the dfrA gene that specifies the S1 dihydrofolate reductase (DHFR) responsible for trimethoprim resistance. The S1 enzyme shows sequence homology with type I and V trimethoprim-resistant DHFRs from Gram-negative bacteria and with chromosomally encoded DHFRs from Gram-positive and Gram-negative bacteria. 5' to dfrA is a thymidylate synthetase gene, designated thyE.

Interleukin-2 protects neonatal mice from lethal herpes simplex virus infection: a macrophage-mediated, gamma interferon-induced mechanism

Administration of human recombinant interleukin-2 (IL-2) protected neonatal mice from a lethal herpes simplex virus (HSV) infection. Protection was not associated with viral antibody production, enhanced natural killer cell cytotoxicity, or intrinsic resistance of macrophages to viral infection. Protection was associated with increased macrophage-mediated antiviral antibody-dependent cellular cytotoxicity (ADCC). Spleen cells from IL-2-treated neonatal mice and from neonatal mice that were treated in vitro with IL-2 transferred protection to neonatal mice. These cells, by adherence, silica, and asialo GM 1 antibody treatment, were shown to be macrophages. IL-2 treatment in vitro enhanced the neonatal macrophages' ADCC function and superoxide release. Similar protection was induced by gamma interferon (IFN-gamma)-treated spleen cells. Antibody to IFN-gamma ablated both IFN-gamma- and IL-2-induced protection by adherent spleen cells. Thus, IL-2-mediated protection against murine neonatal HSV infection was affected by stimulated macrophage activity, via helper T cell-produced IFN-gamma.

Antibody to cloned HSV glycoproteins B and D plus adult human leukocytes protect neonatal mice from lethal HSV infection

Antisera produced by HSV infection or following vaccination of guinea pigs with the cloned herpes simplex virus (HSV) glycoproteins gB and gD were compared for in vitro antibody-dependent cellular cytotoxicity (ADCC) activity and for in vivo protection. Antibody from guinea pigs was able to participate in ADCC with human mononuclear cells in vitro, anti-gBgD serum being equivalent to HSV convalescent sera. In vivo, each of the guinea pig sera was able to protect neonatal mice from a fatal HSV-1 infection when given with human mononuclear cells but not when given alone. The anti-gBgD serum was the most effective in vivo, protecting 15 of 17 (88%) neonatal mice when given at a 10(-4) dilution with human mononuclear cells and was the only guinea pig serum protective at a 10(-6) dilution (5 of 7 neonatal mice).

Use of interleukin-2 and macrophages to treat herpes simplex virus infection in neonatal mice

We have developed a model of therapy for herpes simplex virus (HSV) infection in neonatal mice. Using a lower dose of virus (10(2) plaque-forming units administered intraperitoneally), we have been able to treat infected mice with syngeneic or allogeneic adult mouse macrophages in combination with three doses of human recombinant interleukin-2. Therapy resulted in a 42%-85% survival rate. Although production of antibody to HSV was associated with successful treatment, early administration of antibody did not improve survival.

Defects in interleukin-2 stimulation of neonatal natural killer cytotoxicity to herpes simplex virus-infected cells

Natural killer cytotoxicity (NKC) is an important early defense mechanism in viral infections. We determined the ability of interleukin-2 (IL-2), an NKC stimulator, to enhance defective neonatal NKC to virus-infected cells. Human recombinant IL-2-stimulated adult and cord blood NKC to herpes simplex virus-infected cells in a time-dependent and dose-dependent fashion. The highest level of neonatal IL-2-stimulated cytotoxicity approached the level of unstimulated cytotoxicity when adult cells are used. Single-cell experiments suggested that the cord blood defect was due not to decreased adherence but to lysis or recycling defects. IL-2 stimulated adhesion in the presence of antibody but had no stimulatory effect on antibody-dependent cellular cytotoxicity. The relative defects in IL-2 stimulation of neonatal NKC suggest that its lone use as a therapeutic or protective agent against herpes simplex virus infections is unlikely to be successful, and may require concomitant adult cells if NKC is a critical mechanism.

Defective production of antibody to herpes simplex virus in neonates: defective production of T helper lymphokine and induction of suppression

Defective production of antibodies to herpes simplex virus (HSV) and low resistance to HSV infection in neonatal mice could be reconstituted by using macrophages from syngeneic adult mice plus concanavalin A-stimulated supernatants prepared from adult mouse spleen cells or adult human peripheral blood lymphocytes. In each supernatant, interleukin-2 (IL-2) produced by T helper cells (positive for Lyt 1.2 or OKT4) was necessary to provide reconstitution. Supernatants from neonatal mice failed to mediate reconstitution because of an age-dependent absence of production of IL-2. Although supernatants from neonatal human cell cultures contained IL-2, they failed to reconstitute production of antibody to HSV and resistance to HSV infection because of a suppressor of IL-2 activity. Early antibody production and antibody-dependent cellular effector function are important defenses against HSV infection and are critically defective in the neonate.

Natural killer cell cytotoxicity and antibody-dependent cellular cytotoxicity to herpes simplex virus-infected cells in human pregnancy

Natural killer cell (NKC) cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC) represent the ability of human leukocyte effector cells to destroy target cells in the absence and presence of antibody, respectively. Since these immune systems play a pivotal role in the body's primary lines of defense against a variety of pathogens including herpes simplex virus (HSV), a study was undertaken to evaluate the influence of pregnancy on these systems. Eleven uncomplicated gravidas were followed serially through each trimester and compared to 11 nonpregnant female controls. Mononuclear cells were acquired by Ficoll-Hypaque centrifugation of heparinized blood. Chang liver cells infected with HSV-I were utilized as target cells in a 51Cr release assay. Mean NKC values in the pregnant patients were uniformly lower than in the controls. No similar decreases in ADCC activity were observed in a comparison between the two study populations. These data support previous observations suggesting that pregnancy represents a relatively immunocompromised state. Differences apparently exist between NKC and ADCC effector cell populations with regard to the influence of pregnancy. Although these physiologic alterations in immunoregulation may help support the fetoplacental allograph, detrimental conditions may exist regarding susceptibility to various pathogens such as HSV.

The genetic deficiency of leukocyte surface glycoprotein Mac-1, LFA-1, p150,95 in humans is associated with defective antibody-dependent cellular cytotoxicity in vitro and defective protection against herpes simplex virus infection in vivo

The role of the Mac-1, LFA-1, p150,95 leukocyte glycoprotein family in mediating antiviral host defense was investigated by utilizing mononuclear cells (MC) obtained from eight patients with a genetic deficiency of Mac-1, LFA-1, and p150,95, and normal MC incubated with subunit-specific monoclonal antibodies (MAb) directed against these glycoproteins. As shown with an in vitro chromium-release cytotoxicity assay to herpes simplex virus (HSV)-infected Chang liver target cells, MC of these patients with the severe phenotype or normal MC preincubated with a combination of MAb against Mac-1 glycoprotein subunits were deficient in antibody-dependent cellular cytotoxicity (ADCC). When used individually, MAb directed at LFA-1-alpha or -beta also inhibited ADCC and natural killer cytotoxicity (NKC). In a single cell agarose assay, MC of Mac-1-deficient patients formed fewer effector-target cell conjugates in the presence of specific anti-HSV antibody. To investigate the in vitro contributions of these glycoproteins to cytotoxic host defense mechanisms, two in vivo adoptive transfer models were explored in which neonatal mice are protected against a lethal HSV challenge by normal human MC plus anti-HSV antibody (in vivo ADCC) or human interferon-alpha (NKC stimulated in vivo). In each model, MC from patients with "severe" or "moderate" phenotypes of Mac-1 deficiency, or normal MC incubated with a combination of anti-LFA-alpha, Mac-1-alpha, p150,95-alpha plus -beta MAb failed to protect neonatal mice against lethal HSV infection. These studies further indicate requirements for adhesion-dependent mechanisms in the mediation of MC-ADCC, and suggest that Mac-1-dependent cellular adhesive properties are necessary for normal cytotoxic functions in vivo in experimental models of human ADCC or interferon-stimulated NKC. These findings, in addition to the recognized occurrence of severe or even lethal viral infections in some Mac-1-deficient patients, suggest that glycoproteins of the Mac-1 family may be important determinants of antiviral host defense.

The genetic deficiency of leukocyte surface glycoprotein Mac-1, LFA-1, p150,95 in humans is associated with defective antibody-dependent cellular cytotoxicity in vitro and defective protection against herpes simplex virus infection in vivo

The role of the Mac-1, LFA-1, p150,95 leukocyte glycoprotein family in mediating antiviral host defense was investigated by utilizing mononuclear cells (MC) obtained from eight patients with a genetic deficiency of Mac-1, LFA-1, and p150,95, and normal MC incubated with subunit-specific monoclonal antibodies (MAb) directed against these glycoproteins. As shown with an in vitro chromium-release cytotoxicity assay to herpes simplex virus (HSV)-infected Chang liver target cells, MC of these patients with the severe phenotype or normal MC preincubated with a combination of MAb against Mac-1 glycoprotein subunits were deficient in antibody-dependent cellular cytotoxicity (ADCC). When used individually, MAb directed at LFA-1-alpha or -beta also inhibited ADCC and natural killer cytotoxicity (NKC). In a single cell agarose assay, MC of Mac-1-deficient patients formed fewer effector-target cell conjugates in the presence of specific anti-HSV antibody. To investigate the in vitro contributions of these glycoproteins to cytotoxic host defense mechanisms, two in vivo adoptive transfer models were explored in which neonatal mice are protected against a lethal HSV challenge by normal human MC plus anti-HSV antibody (in vivo ADCC) or human interferon-alpha (NKC stimulated in vivo). In each model, MC from patients with "severe" or "moderate" phenotypes of Mac-1 deficiency, or normal MC incubated with a combination of anti-LFA-alpha, Mac-1-alpha, p150,95-alpha plus -beta MAb failed to protect neonatal mice against lethal HSV infection. These studies further indicate requirements for adhesion-dependent mechanisms in the mediation of MC-ADCC, and suggest that Mac-1-dependent cellular adhesive properties are necessary for normal cytotoxic functions in vivo in experimental models of human ADCC or interferon-stimulated NKC. These findings, in addition to the recognized occurrence of severe or even lethal viral infections in some Mac-1-deficient patients, suggest that glycoproteins of the Mac-1 family may be important determinants of antiviral host defense.

Defective production of anti-herpes simplex virus antibody by neonatal mice. Reconstitution with Ia+ macrophages and T helper lymphocytes from nonimmune adult syngeneic mice

Both neonatal humans and mice are exquisitely susceptible to severe HSV infection. We have now documented a profound defect in the ability of neonatal C57BL/6 mice to produce anti-HSV ADCC antibody. This ability is acquired over the first 2 to 4 wk of life. Reconstitution of neonatal mice by i.p. injection of peritoneal cells from adult nonimmune syngeneic mice both affords dose-dependent protection against lethal HSV infection and reconstitutes the antibody-production defect. By cell-separation techniques (adherence, nylon wool column purification, B cell panning) and cell ablation techniques (silica treatment, irradiation, anti-T cell, anti-Ia, anti-Lyt-1.2 and anti-Lyt-2.2 monoclonal antibodies plus complement treatment) the subpopulations involved in the antibody production reconstitution of neonatal mice by adult cells were identified. These include both an Ia+, radioresistant, adherent, silica-sensitive macrophage population and a nylon wool column-purified, radiosensitive, anti-T, anti-Lyt-1.2-sensitive helper T cell population. The latter cell may be substituted for by concanavalin A-stimulated lymphokine-containing spleen cell supernatants or human recombinant IL 2. In addition to reconstitution of ADCC antibody production, the same cell populations, or cells plus lymphokine-containing supernatants or IL 2, protected the newborn mice from lethal HSV infection. Further characterization of this system and of soluble replacement factors has implications for therapy or immunoprophylaxis of human neonates with, or at risk of, HSV infection.

Defective production of anti-herpes simplex virus antibody by neonatal mice. Reconstitution with Ia+ macrophages and T helper lymphocytes from nonimmune adult syngeneic mice

Both neonatal humans and mice are exquisitely susceptible to severe HSV infection. We have now documented a profound defect in the ability of neonatal C57BL/6 mice to produce anti-HSV ADCC antibody. This ability is acquired over the first 2 to 4 wk of life. Reconstitution of neonatal mice by i.p. injection of peritoneal cells from adult nonimmune syngeneic mice both affords dose-dependent protection against lethal HSV infection and reconstitutes the antibody-production defect. By cell-separation techniques (adherence, nylon wool column purification, B cell panning) and cell ablation techniques (silica treatment, irradiation, anti-T cell, anti-Ia, anti-Lyt-1.2 and anti-Lyt-2.2 monoclonal antibodies plus complement treatment) the subpopulations involved in the antibody production reconstitution of neonatal mice by adult cells were identified. These include both an Ia+, radioresistant, adherent, silica-sensitive macrophage population and a nylon wool column-purified, radiosensitive, anti-T, anti-Lyt-1.2-sensitive helper T cell population. The latter cell may be substituted for by concanavalin A-stimulated lymphokine-containing spleen cell supernatants or human recombinant IL 2. In addition to reconstitution of ADCC antibody production, the same cell populations, or cells plus lymphokine-containing supernatants or IL 2, protected the newborn mice from lethal HSV infection. Further characterization of this system and of soluble replacement factors has implications for therapy or immunoprophylaxis of human neonates with, or at risk of, HSV infection.

Influence of menstrual cycle variations on natural killer cytotoxicity and antibody-dependent cellular cytotoxicity to cells infected with herpes simplex virus

Natural killer cytotoxicity (NKC) and antibody-dependent cellular cytotoxicity (ADCC) represent the ability of human leukocytes to destroy target cells. Those systems have been shown to influence herpes simplex virus (HSV) infections. Prostaglandins are known to inhibit these nonspecific immunologic defenses. Since prostaglandin production varies with the menstrual cycle, this study was undertaken to test for variations in cytotoxic activity against HSV-infected cells during the proliferative, secretory and menstrual phases in 13 normal volunteers. NKC and ADCC activity was not statistically different between the three menstrual phases when testing was done for both mononuclear and polymorphonuclear cells from donor sera. This study suggested that NKC and ADCC cannot be used to explain anecdotal experiences suggesting menstrual variations as a triggering mechanism for HSV recurrences.

Defective natural killer cytotoxicity and polymorphonuclear leukocyte antibody-dependent cellular cytotoxicity in patients with LFA-1/OKM-1 deficiency

Four children with an immunodeficiency involving the absence of leukocyte membrane glycoproteins reacting with anti-LFA-1 and OKM-1 monoclonal antibodies were unable to mediate adherence-dependent leukocyte functions. Even with normal Fc receptor function, their PMN-ADCC and MC-NKC were markedly deficient. Single cell analysis demonstrated deficient antibody-mediated PMN-target cell adherence. Monoclonal antibodies against LFA-1 and OKM-1 reproduced this immunodeficiency in leukocytes from normal adults. LFA-1/OKM-1 mediates a PMN-target cell adhesive step.

Defective natural killer cytotoxicity and polymorphonuclear leukocyte antibody-dependent cellular cytotoxicity in patients with LFA-1/OKM-1 deficiency

Four children with an immunodeficiency involving the absence of leukocyte membrane glycoproteins reacting with anti-LFA-1 and OKM-1 monoclonal antibodies were unable to mediate adherence-dependent leukocyte functions. Even with normal Fc receptor function, their PMN-ADCC and MC-NKC were markedly deficient. Single cell analysis demonstrated deficient antibody-mediated PMN-target cell adherence. Monoclonal antibodies against LFA-1 and OKM-1 reproduced this immunodeficiency in leukocytes from normal adults. LFA-1/OKM-1 mediates a PMN-target cell adhesive step.

Ontogeny of protection of neonatal mice from lethal herpes simplex virus infection by human leukocytes, antiviral antibody, and recombinant alpha-interferon

We have studied the peripheral blood leukocytes from human infants in an assay involving the protection of neonatal mice from herpes simplex virus (HSV) infection by human antibody, interferon, and leukocytes. Recombinant DNA alpha-interferon (IFLrA), antibody, and Ficoll-Hypaque-purified mononuclear cells (MC) from human adults administered intraperitoneally protected neonatal mice from a lethal HSV challenge 1 day later (73.6% survival). MC obtained from human infants less than 130 days old in combination with IFLrA and antibody afforded no protection (15.2% survival; p less than 0.0005 compared to survival with adults' MC). MC from infants over 130 days protected the neonatal mice [60% survival; not significantly different from survival using adult cells, but significantly (p less than 0.0005) different than survival using MC from younger infants]. The ontogeny of MC protection parallels the clinical development of resistance of infants to HSV infection.

Influence of naproxen therapy on natural killer cytotoxicity and antibody-dependent cellular cytotoxicity against cells infected with herpes simplex virus

Natural killer cytotoxicity (NKC) and antibody-dependent cellular cytotoxicity (ADCC) represent one of the body's primary lines of defense against viral infections, including herpes simplex (HSV). This immune defense system is negatively influenced by prostaglandins. A project was undertaken to evaluate the influence of an antiprostaglandin agent in vivo on these cytotoxic effects against cells infected with HSV. Thirteen subjects without previous histories of clinical herpes simplex infection were studied during menses with and without naproxen therapy. A statistically significant augmentation (p = 0.05) of natural killer-cell function was identified in mononuclear cells during therapy. Subjects with baseline cytotoxicity of less than 45% demonstrated consistent elevations during naproxen therapy. No other significant differences could be found for mononuclear or polymorphonuclear cells with regard to NKC and ADCC. There appears to be a subset of patients who may benefit from immunologic augmentation with antiprostaglandin agents when experiencing herpes simplex virus infection.

Analysis in human neonates of defective antibody-dependent cellular cytotoxicity and natural killer cytotoxicity to herpes simplex virus-infected cells

Human neonatal mononuclear cells (MCs) had low antibody-dependent cellular cytotoxicity (ADCC) compared with cells from adults in a chromium-release assay against Chang liver cells infected with herpes simplex virus (HSV). Polymorphonuclear leukocyte (PMNL) ADCC of neonates was similar to that of adults. In a single-cell agarose conjugation assay IgG antibody to HSV significantly increased conjugation by adult MCs, adult PMNLs, and cord blood PMNLs but not by cord blood MCs. Expression of the high-affinity IgG Fc receptor (FcR) assayed by erythrocyte-antibody rosetting revealed significant differences between adult MC FcR and cord blood FcR. There was no difference in PMNL FcR expression. Human interferon-alpha increased neonatal MC adhesion in the presence of IgG and FcR expression, but it had no effect on MC ADCC. Defective FcR expression and target cell adhesion may partly explain low neonatal MC ADCC. In addition, cord blood cells have a lytic or recycle, as well as an adherence, defect.

Antibody-dependent cellular cytotoxicity and natural killer cytotoxicity of peritoneal cells from nude mice to herpes simplex virus-infected cells

Nude BALB/c mice (athymic) were more susceptible to fatal herpes simplex virus (HSV) than normal BALB/c mice (P = 0.002). The peritoneal cells of nude mice mediated levels of antibody-dependent cellular cytotoxicity (ADCC) of equal or greater magnitude than cells from normal BALB/c, heterozygote nu/+, or C57BL/6 mice. Unstimulated natural killer cytotoxicity of peritoneal cells from nude mice was higher (P less than 0.05) than that mediated by cells from C57BL/6 mice. Nude mice failed to make anti-HSV ADCC antibody 6 to 14 days post HSV inoculation, at times when nu/+, BALB/c, and C57BL/6 mice produced antibody. Passive reconstitution of nude mice with high titer intraperitoneal anti-HSV immune globulin provided circulating anti-HSV ADCC antibody and significant protection against lethal HSV infection.

The relative role of transplacental and milk immune transfer in protection against lethal neonatal herpes simplex virus infection in mice

The role of passive maternal immunity in neonatal herpes simplex virus (HSV) infection is controversial. C57BL/6 mice born to HSV-immune mothers had significantly greater survival than those born to nonimmune mothers after an intraperitoneal or oral HSV challenge. In subsequent experiments with intraperitoneal and oral HSV challenge, non-immune mice that were foster fed for one week by actively or passively immunized mothers were significantly protected. Injections of passive antibody postpartum in nonimmune mother mice resulted in detectable transfer of antibody to HSV to their infant mice via breast milk. In mice, maternal breast milk, not transplacentally derived antibody, protects neonates from low-dose HSV infection.

Murine cellular cytotoxicity to syngeneic and xenogeneic herpes simplex virus-infected cells

Cellular cytotoxicity of C57BL/6 adult mice peritoneal cells to xenogeneic (Chang liver) and syngeneic (BL/6-WT3) herpes simplex virus (HSV)-infected cells was analyzed in a 6-h 51Cr release assay. There was no difference in antibody-dependent cellular cytotoxicity to either target. There was no natural killer cytotoxicity to targets with cells from uninfected mice except at very high effector cell ratios. HSV-infected (2 X 10(4) PFU intraperitoneally 1 day previously) mice mediated significantly higher antibody-dependent cellular cytotoxicity and required less antibody (10(-5) versus 10(-2) dilution), fewer cells, and less time to kill than cells from uninfected mice. HSV-infected mice mediated natural killer cytotoxicity but preferentially killed syngeneic HSV-infected cells. Stimulation of cytotoxicity was not virus specific since influenza-infected mice mediated similar levels of cytotoxicity to HSV-infected targets. There was no difference in morphology (95% macrophage) or in the percentage of FcR-positive cells, but infected mice had more peritoneal cells and generated higher levels of superoxide in response to opsonized zymosan or phorbolmyristate acetate. These data demonstrate nonspecific virus-stimulated metabolic and effector cell function which may enhance clearance of virus in an infected host.

Indomethacin enhancement of human natural killer cytotoxicity to herpes simplex virus infected cells in vitro and in vivo

Indomethacin, a prostaglandin synthetase inhibitor, increased human mononuclear cell (MC) natural killer cytotoxicity (NKC) to herpes simplex virus (HSV) infected cells in vitro at concentrations of 2 X 10(-10)M (p less than .025). Infant mice were significantly (p less than 0.025) protected from a lethal HSV infection by prior injection with a combination of MC and indomethacin (60.7% survival) although neither alone was protective. These results further support the probable in vivo role of NKC in protection against HSV infection, and the critical regulation of NKC by prostaglandins.

Protection of neonatal mice against herpes simplex virus infection: probable in vivo antibody-dependent cellular cytotoxicity

Infant mice are extremely susceptible to fatal Herpes simplex virus (HSV) infection. They are unable to produce antibody to HSV, and their leukocytes cannot mediate antibody-dependent cellular cytotoxicity (ADCC) to HSV-infected cells. In order to avoid H-2-dependent effector mechanisms and instead analyze possible in vivo ADCC, a murine model employing adoptive transfer of antibody and human leukocytes was developed. Administration of either human immune globulin or leukocytes i.p. from HSV immune or nonimmune humans could not protect infant C57BL/6 mice from fatal HSV infection. In contrast, a combination of a subneutralizing dilution of globulin and leukocytes from nonimmune or immune human donors, given one day before inoculation, was highly protective against lethal HSV infection. The cells involved included lymphocytes or monocyte-macrophages. At least 5 X 10(6) viable leukocytes (or 1 X 10(6) monocyte-macrophages) and immune serum globulin concentrations as low as 10(-8) were protective. Infected cell monolayer adsorption and DEAE column fractionation demonstrated that the protection by globulin was due to specific antiviral IgG antibody. Protection was n ot seen in animals receiving virus before immune transfer. Protection did not involve synergistic viral neutralization by antibody and cells, as shown by in vitro experiments. Animals receiving globulin and cells, unlike normal infant mice, had circulating antiviral antibody and peritoneal leukocytes able to mediate ADCC to HSV-infected cells. This is the first in vivo evidence for the role of human ADCC. This model also allows for the in vivo evaluation of the ability of cells from immunocompromised humans to curb viral infection.

Protection of neonatal mice against herpes simplex virus infection: probable in vivo antibody-dependent cellular cytotoxicity

Infant mice are extremely susceptible to fatal Herpes simplex virus (HSV) infection. They are unable to produce antibody to HSV, and their leukocytes cannot mediate antibody-dependent cellular cytotoxicity (ADCC) to HSV-infected cells. In order to avoid H-2-dependent effector mechanisms and instead analyze possible in vivo ADCC, a murine model employing adoptive transfer of antibody and human leukocytes was developed. Administration of either human immune globulin or leukocytes i.p. from HSV immune or nonimmune humans could not protect infant C57BL/6 mice from fatal HSV infection. In contrast, a combination of a subneutralizing dilution of globulin and leukocytes from nonimmune or immune human donors, given one day before inoculation, was highly protective against lethal HSV infection. The cells involved included lymphocytes or monocyte-macrophages. At least 5 X 10(6) viable leukocytes (or 1 X 10(6) monocyte-macrophages) and immune serum globulin concentrations as low as 10(-8) were protective. Infected cell monolayer adsorption and DEAE column fractionation demonstrated that the protection by globulin was due to specific antiviral IgG antibody. Protection was n ot seen in animals receiving virus before immune transfer. Protection did not involve synergistic viral neutralization by antibody and cells, as shown by in vitro experiments. Animals receiving globulin and cells, unlike normal infant mice, had circulating antiviral antibody and peritoneal leukocytes able to mediate ADCC to HSV-infected cells. This is the first in vivo evidence for the role of human ADCC. This model also allows for the in vivo evaluation of the ability of cells from immunocompromised humans to curb viral infection.

The effect of route of delivery on neonatal natural killer cytotoxicity and antibody-dependent cellular cytotoxicity to herpes simplex virus-infected cells

The ability of human neonatal and adult Ficoll-hypaque purified mononuclear cells to mediate natural killer cytotoxicity (NKC) and antibody-dependent cellular-cytotoxicity (ADCC) against 51Cr labeled herpes simplex virus-infected (HSV-infected) and uninfected cells was evaluated in healthy term infants delivered vaginally or by Cesarean (C)-section without labor, and in healthy adult controls. Cord blood NKC to HSV-infected cells (12.5 +/- 7.0) was lower (P less than 0.01) than adult controls NKC (29.5 +/- 7.0). NKC to HSV-infected cells of babies delivered vaginally (16.6 +/- 3.4) was lower (P less than 0.05) than adult controls (28.4 +/- 4.2). NKC to HSV-infected cells of neonates delivered by C-section without labor (7.6 +/- 2.8) was also lower (P less than 0.001) than adult controls (30.7 +/- 4.0) and lower (P less than 0.05) than that of neonates delivered vaginally. Cord blood ADCC (43.1 +/- 9.0) was lower (P less than 0.05) than ADCC of adult controls (58 +/- 10). ADCC of neonates delivered vaginally (50 +/- 5.9) was similar to ADCC of adult controls (57.4 +/- 6.9). ADCC of neonates delivered by C-section without labor (30.4 +/- 7.2) was lower than ADCC of adult (58.5 +/- 7.4) and was lower (P less than 0.05) than ADCC of neonates delivered vaginally. These findings demonstrate that the method of delivery influences subsequent neonatal leukocyte NKC and ADCC. Further experiments will delineate the cause of these variations, which probably include labor or stress related hormonal changes in the mother or neonate.

Inhibition of cellular cytotoxicity of leukocytes for herpes simplex virus-infected cells in vitro and in vivo by intralipid

The effect of intralipid, a lipid emulsion used in total parenteral nutrition, on cellular cytotoxicity for herpes simplex virus (HSV)-infected cells was analyzed. In vitro, intralipid inhibited antibody-dependent cellular cytotoxicity (ADCC) of lymphocytes, monocytes-macrophages, and polymorphonuclear leukocytes and natural killer cytotoxicity of lymphocytes for radiolabeled HSV-infected liver cells. This was due to an effect on the leukocytes, rather than on the target cells. Intralipid did not affect leukocyte viability but inhibited the expression of leukocyte Fc receptors necessary for cytotoxicity. In vivo, intralipid inhibited murine ADCC and completely nullified the protection against lethal infection with HSV in neonatal mice afforded by the administration of human leukocytes and antibody. These data suggest that high levels of circulating intralipid may interfere with antiviral immunity in humans and predispose hosts who are already compromised to severe viral infections.