Alarmin S100A11 initiates a chemokine response to the human pathogen Toxoplasma gondii.

Toxoplasma gondii is a common protozoan parasite that infects up to one third of the world's population. Notably, very little is known about innate immune sensing mechanisms for this obligate intracellular parasite by human cells. Here, by applying an unbiased biochemical screening approach, we show that human monocytes recognized the presence of T. gondii infection by detecting the alarmin S100A11 protein, which is released from parasite-infected cells via caspase-1-dependent mechanisms. S100A11 induced a potent chemokine response to T. gondii by engaging its receptor RAGE, and regulated monocyte recruitment in vivo by inducing expression of the chemokine CCL2. Our experiments reveal a sensing system for T. gondii by human cells that is based on the detection of infection-mediated release of S100A11 and RAGE-dependent induction of CCL2, a crucial chemokine required for host resistance to the parasite.

A noncanonical role for the engulfment gene ELMO1 in neutrophils that promotes inflammatory arthritis.

Rheumatoid arthritis is characterized by progressive joint inflammation and affects ~1% of the human population. We noted single-nucleotide polymorphisms (SNPs) in the apoptotic cell-engulfment genes ELMO1, DOCK2, and RAC1 linked to rheumatoid arthritis. As ELMO1 promotes cytoskeletal reorganization during engulfment, we hypothesized that ELMO1 loss would worsen inflammatory arthritis. Surprisingly, Elmo1-deficient mice showed reduced joint inflammation in acute and chronic arthritis models. Genetic and cell-biology studies revealed that ELMO1 associates with receptors linked to neutrophil function in arthritis and regulates activation and early neutrophil recruitment to the joints, without general inhibition of inflammatory responses. Further, neutrophils from the peripheral blood of human donors that carry the SNP in ELMO1 associated with arthritis display increased migratory capacity, whereas ELMO1 knockdown reduces human neutrophil migration to chemokines linked to arthritis. These data identify 'noncanonical' roles for ELMO1 as an important cytoplasmic regulator of specific neutrophil receptors and promoter of arthritis.

Pannexin 1 channels facilitate communication between T cells to restrict the severity of airway inflammation.

Allergic airway inflammation is driven by type-2 CD4+ T cell inflammatory responses. We uncover an immunoregulatory role for the nucleotide release channel, Panx1, in T cell crosstalk during airway disease. Inverse correlations between Panx1 and asthmatics and our mouse models revealed the necessity, specificity, and sufficiency of Panx1 in T cells to restrict inflammation. Global Panx1-/- mice experienced exacerbated airway inflammation, and T-cell-specific deletion phenocopied Panx1-/- mice. A transgenic designed to re-express Panx1 in T cells reversed disease severity in global Panx1-/- mice. Panx1 activation occurred in pro-inflammatory T effector (Teff) and inhibitory T regulatory (Treg) cells and mediated the extracellular-nucleotide-based Treg-Teff crosstalk required for suppression of Teff cell proliferation. Mechanistic studies identified a Salt-inducible kinase-dependent phosphorylation of Panx1 serine 205 important for channel activation. A genetically targeted mouse expressing non-phosphorylatable Panx1S205A phenocopied the exacerbated inflammation in Panx1-/- mice. These data identify Panx1-dependent Treg:Teff cell communication in restricting airway disease.

Estimating the effect of latent time-varying count exposures using multiple lists.

A major challenge in longitudinal built-environment health studies is the accuracy of commercial business databases that are used to characterize dynamic food environments. Different databases often provide conflicting exposure measures on the same subject due to different source credibilities. As on-site verification is not feasible for historical data, we suggest combining multiple databases to correct the bias in health effect estimates due to measurement error in any 1 datasource. We propose a joint model for the time-varying health outcomes, observed count exposures, and latent true count exposures. Our model estimates the time-specific quality of sources and incorporates time dependence of true count exposure by Poisson integer-valued first-order autoregressive process. We take a Bayesian nonparametric approach to flexibly account for location-specific exposures. By resolving the discordance between different databases, our method reduces the bias in the longitudinal health effect of the true exposures. Our method is demonstrated with childhood obesity data in California public schools with respect to convenience store exposures in school neighborhoods from 2001 to 2008.

Distress about social problems and tobacco and cannabis use outcomes among young adults in Los Angeles County.

OBJECTIVE: To examine associations of concern, worry, and stress about discrimination, shootings/violence, and police brutality and exclusive and dual tobacco and cannabis use among young adults. METHODS: A prospective, racially/ethnically diverse cohort of young adults (n = 1960) living in Los Angeles, California completed a baseline survey in 2020 (age range: 19-23) and a follow-up survey in 2021. Exploratory factor analysis (EFA) was employed on nine variables assessing levels of concern, worry, and stress about societal discrimination, societal shootings/violence, and community police brutality at baseline. Past 30-day tobacco and cannabis use at follow-up was categorized as current exclusive tobacco, exclusive cannabis, and dual tobacco and cannabis (vs never/former) use based on eleven use variables. Multinomial logistic regressions estimated adjusted associations between each factor score (translated to standard deviation units) with exclusive and dual tobacco and cannabis use. RESULTS: The EFA produced four factor scores representing concern/worry/stress (i.e., distress) about community police brutality (F1), distress about societal shootings/violence (F2), and distress about societal discrimination (F3), as well as generalized stress about police brutality, shootings/violence, and discrimination (F4). F1, F2, and F3 were associated with subsequent exclusive current cannabis use, with F1 having the strongest association (OR: 1.35, 95% CI: 1.18-1.55), while only F1 (OR: 1.51, 95% CI: 1.27-1.78) was associated with dual tobacco and cannabis use. None of the factors were associated with exclusive tobacco use. CONCLUSIONS: Young adult concern, worry, and/or stress about social problems may increase risk of cannabis use with or without concurrent tobacco use 6-12 months later.

Surrogacy validation for time-to-event outcomes with illness-death frailty models.

A common practice in clinical trials is to evaluate a treatment effect on an intermediate outcome when the true outcome of interest would be difficult or costly to measure. We consider how to validate intermediate outcomes in a causally-valid way when the trial outcomes are time-to-event. Using counterfactual outcomes, those that would be observed if the counterfactual treatment had been given, the causal association paradigm assesses the relationship of the treatment effect on the surrogate outcome with the treatment effect on the true, primary outcome. In particular, we propose illness-death models to accommodate the censored and semicompeting risk structure of survival data. The proposed causal version of these models involves estimable and counterfactual frailty terms. Via these multistate models, we characterize what a valid surrogate would look like using a causal effect predictiveness plot. We evaluate the estimation properties of a Bayesian method using Markov chain Monte Carlo and assess the sensitivity of our model assumptions. Our motivating data source is a localized prostate cancer clinical trial where the two survival outcomes are time to distant metastasis and time to death.

Neighborhood racial income inequality and cognitive health.

INTRODUCTION: Neighborhood socioeconomic status (SES) has been linked to dementia, but the distribution of SES within a neighborhood may also matter. METHODS: Data from 460 (47% Black, 46% White) older adults from the Michigan Cognitive Aging Project were linked to census tract-level data from the National Neighborhood Data Archive (NaNDA). Neighborhood SES included two composites reflecting disadvantage and affluence. Neighborhood racial income inequality was the ratio of median incomes for White versus Black residents. Generalized estimating equations examined associations between neighborhood factors and cognitive domains. RESULTS: Neighborhood racial income inequality was uniquely associated with worse cognitive health, and these associations did not differ by participant race. Neighborhood disadvantage was only associated with worse cognitive health among Black participants. DISCUSSION: Both the level and racial distribution of SES within a neighborhood may be relevant for dementia risk. Racial differences in the level and impact of neighborhood SES contribute to dementia inequalities. HIGHLIGHTS: Black participants lived in neighborhoods with lower socioeconomic status (SES) than White participants, on average. Neighborhood SES and racial income inequality were associated with worse cognition. Effects of neighborhood racial income inequality did not differ across racial groups. Effects of neighborhood SES were only evident among Black participants.

Solutions for surrogacy validation with longitudinal outcomes for a gene therapy.

Valid surrogate endpoints S can be used as a substitute for a true outcome of interest T to measure treatment efficacy in a clinical trial. We propose a causal inference approach to validate a surrogate by incorporating longitudinal measurements of the true outcomes using a mixed modeling approach, and we define models and quantities for validation that may vary across the study period using principal surrogacy criteria. We consider a surrogate-dependent treatment efficacy curve that allows us to validate the surrogate at different time points. We extend these methods to accommodate a delayed-start treatment design where all patients eventually receive the treatment. Not all parameters are identified in the general setting. We apply a Bayesian approach for estimation and inference, utilizing more informative prior distributions for selected parameters. We consider the sensitivity of these prior assumptions as well as assumptions of independence among certain counterfactual quantities conditional on pretreatment covariates to improve identifiability. We examine the frequentist properties (bias of point and variance estimates, credible interval coverage) of a Bayesian imputation method. Our work is motivated by a clinical trial of a gene therapy where the functional outcomes are measured repeatedly throughout the trial.

A statewide population-based approach to examining Long COVID symptom prevalence and predictors in Michigan.

OBJECTIVE: The current broad definition of Long COVID, and an overreliance on clinical and convenience samples, is leading to a wide array of Long COVID estimates with limited generalizability. Our objective was to examine Long COVID symptoms using a statewide population-based probability sample. METHODS: Among 8000 sampled adults with polymerase-chain-reaction-confirmed SARS-CoV-2 between June 2020 and July 2021 in the Michigan Disease Surveillance System, 2533 completed our survey (response rate 32.2%). Using modified Poisson regression, we examined sociodemographic, behavioral, and clinical predictors of eight Long COVID symptom clusters, defined as at least one applicable symptom lasting 90 or more days post COVID-19 onset. RESULTS: Neuropsychiatric Long COVID symptoms, including brain fog, were most prevalent (23.7%), followed by systemic symptoms (17.1%), including fatigue, musculoskeletal (11.4%), pulmonary (10.4%), dermatologic (6.7%), cardiovascular (6.1%), gastrointestinal (5.4%), and ear, nose, and throat symptoms (5.3%). In adjusted analyses, female sex, a pre-existing psychological condition, and intensive care unit admission were strong predictors of most Long COVID symptom clusters. Older age was not associated with a higher prevalence of all symptoms - cardiovascular and dermatologic symptoms were most prevalent among middle-aged adults and age was not associated with neuropsychiatric or gastrointestinal symptoms. Additionally, there were fewer associations between pre-existing conditions and cardiovascular, neuropsychiatric, and dermatologic symptoms compared to other symptom clusters. CONCLUSIONS: While many predictors of Long COVID symptom clusters were similar, the relationship with age and pre-existing conditions varied across clusters. Cardiovascular, neuropsychiatric, and dermatologic symptoms require further study as potentially distinct from other Long COVID symptoms.

Cigarette Prices and Disparities in Cessation in the United States.

INTRODUCTION: Achieving cessation in people with established smoking patterns remains a challenge. Increasing cigarette prices has been one of the most effective strategies for lowering smoking rates. It remains unclear how effective it has been in encouraging cessation among adults in recent years and how the effectiveness varies by sociodemographic characteristics. METHODS: Using repeated cross-sectional data collected by the Tobacco Use Supplement of the Current Population Survey, we investigate the relationship between cigarette prices and cessation from 2003 to 2019 in adults 25+. We examine the associations between price and cessation in the population overall and by sex, race/ethnicity, and socioeconomic status. RESULTS: We found mixed support for associations between greater local prices and cessation. Unadjusted models showed that greater local prices were associated with greater odds of cessation, but the associations did not persist after controlling for sociodemographic characteristics. The associations did not significantly differ by respondent characteristics. Sensitivity analysis using alternative specifications and retail state price as the main predictor showed similar results. Sensitivity analysis with controls for e-cigarette use in the 2014-2019 period showed that greater local price was associated with cessation among adults with less than a high school degree. When stratified by year of data collection, results show that greater local prices were associated with cessation after 2009. CONCLUSIONS: Overall, the study adds to the conflicting evidence on the effectiveness of increasing prices on smoking cessation among adults with established smoking patterns. IMPLICATIONS: Higher cigarette prices have been one of the most effective tools for lowering smoking prevalence. It remains unclear how effective they are in encouraging adults with established smoking patterns to quit. Results show that greater local prices were associated with higher odds of cessation, but the association did not persist after sociodemographic adjustment. In a sensitivity analysis, greater local price was associated with cessation among people with less than a high school degree in models controlling for e-cigarette use. We also found evidence that greater local price was associated with cessation after 2009. More comprehensive smoke-free coverage was also associated with greater odds of cessation. The study's results highlight that encouraging cessation among adults with an established smoking pattern remains a challenging policy problem even when cigarette prices rise.

Death in the CNS: six-microns-under.

During embryonic development, large numbers of apoptotic cells are rapidly cleared by phagocytes. In this issue, Kurant et al. (2008) describe a new phagocytic receptor, called six-microns-under (SIMU), that promotes engulfment of apoptotic neurons by glial cells in the developing nervous system of Drosophila.

Differential impact of the Canadian point-of-sale tobacco display bans on quit attempts and smoking cessation outcomes by sex, income and education: longitudinal findings from the ITC Canada Survey.

SIGNIFICANCE: This study examines the differential effects of Canadian point-of-sale (POS) tobacco display bans across provinces on quit attempts and smoking cessation, by sex, education and income. METHODS: We analysed survey data from five waves (waves 4-8) of the International Tobacco Control Canada Survey, a population-based, longitudinal survey, where provinces implemented display bans between 2004 and 2010. Primary outcomes were quit attempts and successful cessation. We used generalised estimating equation Poisson regression models to estimate associations between living in a province with or without a POS ban (with a 24-month threshold) and smoking outcomes. We tested whether these associations varied by sex, education and income by including interaction terms. RESULTS: Across survey waves, the percentage of participants in provinces with POS bans established for more than 24 months increased from 5.0% to 95.8%. There was no association between POS bans and quit attempts for provinces with bans in place for 0-24 months or more than 24 months, respectively (adjusted relative risk (aRR)=0.99, 95% CI: 0.89 to 1.10; 1.03, 95% CI: 0.88 to 1.20). However, we found a differential impact of POS bans on quit attempts by sex, whereby bans were more effective for women than men for bans of 0-24 months. Participants living in a province with a POS ban for at least 24 months had a higher chance of successful cessation (aRR=1.49; 95% CI: 1.08 to 2.05) compared with those in a province without a ban. We found no differences in the association between POS bans and quit attempts or cessation by education or income, and no differences by sex for cessation. CONCLUSION: POS bans are associated with increased smoking cessation overall and more quit attempts among women than men.

Differential care-seeking behaviors during the beginning of the COVID-19 pandemic in Michigan: a population-based cross-sectional study.

BACKGROUND: At the beginning of the COVID-19 pandemic in the United States in the spring of 2020, many Americans avoided the healthcare system, while those with COVID-19 symptoms were faced with decisions about seeking healthcare services for this novel virus. METHODS: Using a probability sample (n = 1088) from the Michigan adult population of PCR-confirmed COVID-19 cases who were diagnosed prior to July 31, 2020, we used logistic regression to examine sociodemographic and symptom severity predictors of care-seeking behaviors. The analyses examined three different outcomes: (1) whether respondents sought care and, among those who sought care, whether they sought care from (2) a primary care provider or (3) an emergency room. Final models were adjusted for sex, age, race and ethnicity, income, education, marital status, living arrangement, health insurance, and self-reported symptom severity. RESULTS: We found that participants ages 65 and older had 4.00 times higher odds of seeking care than 18-34-year-olds (95% CI: 2.21, 7.24), while adults reporting very severe symptoms had roughly 15 times higher odds of seeking care than those with mild symptoms (95% CI: 7.73, 27.01). Adults who were non-Hispanic Black or were uninsured had lower odds of seeking care from a primary care physician versus seeking care from other locations in comparison to adults who were non-Hispanic White or were privately insured, respectively (non-Hispanic Black: aOR = 0.27, 95% CI: 0.16, 0.44; Uninsured: aOR = 0.19, 95% CI: 0.09, 0.42). Conversely, adults who were older or reported more severe symptoms had higher odds of seeking care from an emergency room versus other locations in comparison to adults who were younger or reported less severe symptoms (Age 65+: aOR = 2.96, 95% CI: 1.40, 6.28; Very Severe Symptoms: aOR = 6.63, 95% CI: 3.33, 13.20). CONCLUSIONS: Our results suggest differential utilization of healthcare services early in the COVID-19 pandemic. Further analyses are needed to examine the reasons for these differences.

Patterns and predictors of depressive and anxiety symptoms within a population-based sample of adults diagnosed with COVID-19 in Michigan.

PURPOSE: The COVID-19 pandemic has had wide-ranging impacts on mental health, however, less is known about predictors of mental health outcomes among adults who have experienced a COVID-19 diagnosis. We examined the intersection of demographic, economic, and illness-related predictors of depressive and anxiety symptoms within a population-based sample of adults diagnosed with COVID-19 in the U.S. state of Michigan early in the pandemic. METHODS: Data were from a population-based survey of Michigan adults who experienced a COVID-19 diagnosis prior to August 1, 2020 (N = 1087). We used weighted prevalence estimates and multinomial logistic regression to examine associations between mental health outcomes (depressive symptoms, anxiety symptoms, and comorbid depressive/anxiety symptoms) and demographic characteristics, pandemic-associated changes in accessing basic needs (accessing food/clean water and paying important bills), self-reported COVID-19 symptom severity, and symptom duration. RESULTS: Relative risks for experiencing poor mental health outcomes varied by sex, age, race/ethnicity, and income. In adjusted models, experiencing a change in accessing basic needs associated with the pandemic was associated with higher relative risks for anxiety and comorbid anxiety/depressive symptoms. Worse COVID-19 symptom severity was associated with a higher burden of comorbid depressive/anxiety symptoms. "Long COVID" (symptom duration greater than 60 days) was associated with all outcomes. CONCLUSION: Adults diagnosed with COVID-19 may face overlapping risk factors for poor mental health outcomes, including pandemic-associated disruptions to household and economic wellbeing, as well as factors related to COVID-19 symptom severity and duration. An integrated approach to treating depressive/anxiety symptoms among COVID-19 survivors is warranted.

Exploring the Potential for Smoke-Free Laws to Reduce Smoking Disparities by Sexual Orientation in the USA.

BACKGROUND: We examined associations between smoke-free laws and smoking outcomes in a nationally representative sample of US adults, including exploring whether these associations differed for heterosexual and sexual minority (SM) adults. METHODS: We constructed county-level variables representing the percent of the population covered by state-, county-, or city-level smoke-free laws in workplaces and hospitality venues. We combined this information with restricted individual-level adult data with masked county identifiers from the National Health Interview Survey (NHIS), 2013-2018. We used modified Poisson regression to explore associations between each type of smoke-free law and the prevalence ratio (PR) of current smoking, and we used linear regression to explore associations with smoking intensity (mean cigarettes per day). We assessed interactions between smoke-free laws and SM status on the additive scale to determine whether associations were different for SM and heterosexual adults. RESULTS: In adjusted models without interaction terms, smoke-free laws in hospitality venues were associated with lower prevalence of current smoking (PR = 0.93, 95% confidence interval (CI) = 0.89, 0.98). Both types of smoke-free laws were associated with lower mean cigarettes per day (workplace law change in mean = - 0.50, 95% CI = - 0.89, - 0.12; hospitality law change in mean = - 0.72, 95% CI = - 1.14,-0.30). We did not observe any statistically significant interactions by SM status, though statistical power was limited. CONCLUSIONS: We did not find evidence that smoke-free laws were differentially associated with smoking outcomes for heterosexual and SM adults. Additional studies are needed to further explore the potential for tobacco control policies to address the elevated risk of smoking in SM communities.

Latent Classes of Tobacco and Cannabis Use among Youth and Young Adults in the United States.

Background: Research characterizing patterns of tobacco and cannabis use by product type and route of administration among youth and young adults (YAs) is limited. Methods: We conducted latent class analysis of tobacco and cannabis use (i.e., cigarettes, electronic nicotine delivery systems (ENDS), cigars, blunts, cannabis vaping, and other cannabis use (without blunting/vaping)) among youth (ages 15-17) and YAs (ages 18-24) who used at least one product in the past 30 days, using data from the Population Assessment of Tobacco and Health Study (Wave 4, 2016-2017). We used multinomial logistic regression models to examine associations between sociodemographic characteristics and use classes. Results: The latent use classes for youth included cigarettes (2.5%), ENDS (2.6%), blunts (2.5%), other cannabis (6.3%), ENDS + cannabis vaping (2.7%), and cigarettes + cigars + other cannabis (1.5%), while the latent use classes for YAs included cigarettes (11.7%), ENDS (3.9%), blunts (5.3%), other cannabis (7.0%), cigarettes + cigars (8.2%), and cigarettes + ENDS + cannabis vaping (4.9%). We compared use classes to never/former use for youth (82.0%) and YAs (59.0%) and found that they differed by each sociodemographic characteristic. For example, non-Hispanic Black YAs had higher odds of cigarettes + cigar use compared to non-Hispanic White YAs, whereas racial/ethnic minority youth and YAs had lower odds of other dual/poly use groups compared to their non-Hispanic White counterparts. Conclusions: We observed differences in use classes by sociodemographic characteristics for youth and YAs. Health professionals must consider tobacco and cannabis use patterns when implementing prevention and cessation interventions.

High-resolution quantification of discrete phagocytic events by live cell time-lapse high-content microscopy imaging.

Phagocytosis is a dynamic process central to immunity and tissue homeostasis. Current methods for quantification of phagocytosis largely rely on indirect or static measurements, such as target clearance or dye uptake, and thus provide limited information about engulfment rates or target processing. Improved kinetic measurements of phagocytosis could provide useful, basic insights in many areas. We present a live-cell, time-lapse and high-content microscopy imaging method based on the detection and quantification of fluorescent dye 'voids' within phagocytes that result from target internalization to quantify phagocytic events with high temporal resolution. Using this method, we measure target cell densities and antibody concentrations needed for optimal antibody-dependent cellular phagocytosis. We compare void formation and dye uptake methods for phagocytosis detection, and examine the connection between target cell engulfment and phagolysosomal processing. We demonstrate how this approach can be used to measure distinct forms of phagocytosis, and changes in macrophage morphology during phagocytosis related to both engulfment and target degradation. Our results provide a high-resolution method for quantifying phagocytosis that provides opportunities to better understand the cellular and molecular regulation of this fundamental biological process.

Gas6 induces inflammation and reduces plaque burden but worsens behavior in a sex-dependent manner in the APP/PS1 model of Alzheimer's disease.

BACKGROUND: Alzheimer's disease is the leading cause of dementia worldwide. TAM receptor tyrosine kinases (Tyro3, Axl, MerTK) are known for their role in engagement of phagocytosis and modulation of inflammation, and recent evidence suggests a complex relationship between Axl, Mer, and microglial phagocytosis of amyloid plaques in AD. Gas6, the primary CNS TAM ligand, reduces neuroinflammation and improves outcomes in murine models of CNS disease. Therefore, we hypothesized that AAV-mediated overexpression of Gas6 would alleviate plaque pathology, reduce neuroinflammation, and improve behavior in the APP/PS1 model of Alzheimer's disease. METHODS: Adeno-associated viral vectors were used to overexpress Gas6 in the APP/PS1 model of Alzheimer's disease. Nine-month-old male and female APP/PS1 and nontransgenic littermates received bilateral stereotactic hippocampal injections of AAV-Gas6 or AAV-control, which expresses a non-functional Gas6 protein. One month after injections, mice underwent a battery of behavioral tasks to assess cognitive function and brains were processed for immunohistochemical and transcriptional analyses. RESULTS: Gas6 overexpression reduced plaque burden in male APP/PS1 mice. However, contrary to our hypothesis, Gas6 increased pro-inflammatory microglial gene expression and worsened contextual fear conditioning compared to control-treated mice. Gas6 overexpression appeared to have no effect on phagocytic mechanisms in vitro or in vivo as measured by CD68 immunohistochemistry, microglial methoxy-04 uptake, and primary microglial uptake of fluorescent fibrillar amyloid beta. CONCLUSION: Our data describes a triad of worsened behavior, reduced plaque number, and an increase in proinflammatory signaling in a sex-specific manner. While Gas6 has historically induced anti-inflammatory signatures in the peripheral nervous system, our data suggest an alternative, proinflammatory role in the context of Alzheimer's disease pathology.

Macrophage hypophagia as a mechanism of innate immune exhaustion in mAb-induced cell clearance.

Macrophage antibody (Ab)-dependent cellular phagocytosis (ADCP) is a major cytotoxic mechanism for both therapeutic unconjugated monoclonal Abs (mAbs) such as rituximab and Ab-induced hemolytic anemia and immune thrombocytopenia. Here, we studied the mechanisms controlling the rate and capacity of macrophages to carry out ADCP in settings of high target/effector cell ratios, such as those seen in patients with circulating tumor burden in leukemic phase disease. Using quantitative live-cell imaging of primary human and mouse macrophages, we found that, upon initial challenge with mAb-opsonized lymphocytes, macrophages underwent a brief burst (<1 hour) of rapid phagocytosis, which was then invariably followed by a sharp reduction in phagocytic activity that could persist for days. This previously unknown refractory period of ADCP, or hypophagia, was observed in all macrophage, mAb, and target cell conditions tested in vitro and was also seen in vivo in Kupffer cells from mice induced to undergo successive rounds of αCD20 mAb-dependent clearance of circulating B cells. Importantly, hypophagia had no effect on Ab-independent phagocytosis and did not alter macrophage viability. In mechanistic studies, we found that the rapid loss of activating Fc receptors from the surface and their subsequent proteolytic degradation were the primary mechanisms responsible for the loss of ADCP activity in hypophagia. These data suggest hypophagia is a critical limiting step in macrophage-mediated clearance of cells via ADCP, and understanding such limitations to innate immune system cytotoxic capacity will aid in the development of mAb regimens that could optimize ADCP and improve patient outcome.

Impact of the Tips From Former Smokers Anti-Smoking Media Campaign on Youth Smoking Behaviors and Anti-Tobacco Attitudes.

INTRODUCTION: Anti-tobacco media campaigns can prevent youth smoking, but there is little research on how adult-targeted campaigns affect youth. We investigated the association between the Tips From Former Smokers (Tips) campaign and youth smoking behaviors and anti-tobacco attitudes, and variation by sex, race and/or ethnicity, or socioeconomic status. AIMS AND METHODS: We used data from the monitoring of the future study, a nationally representative survey on 8th, 10th, and 12th graders, from 2013-2015. Quartiles of Tips gross rating points (GRPs) were used to estimate exposure. Youth smoking behavior outcomes included smoking prevalence, initiation, and susceptibility. The anti-tobacco attitude outcomes included the extent that anti-tobacco ads made participants (1) less favorable towards smoking or (2) less likely to smoke cigarettes. Modified Poisson regression models estimated average marginal effects; separate additive interactions between Tips GRP exposure and sex, race and/or ethnicity, parents' highest education, and college plans (12th graders only) were used to test for effect modification. RESULTS: Tips GRPs were not associated with smoking behaviors within any grade. However, 12th graders in the highest quartile of Tips had a 7.0 percentage point higher probability (95% CI = 0.023-0.116) of responding that anti-tobacco ads made them less likely to smoke. Tips GRPs were associated with a lower probability of past 30-day smoking prevalence among 10th grade females, but not males (joint P-value = .002). No additional statistically significant interactions were found for any other outcomes for any grade. CONCLUSIONS: This study revealed the potential for adult-targeted campaigns to increase youth's anti-smoking attitudes, but campaign exposure was not associated with smoking behaviors. IMPLICATIONS: Few studies have examined the potential for anti-smoking media campaigns to influence audiences outside their targeted audience. In this study, we show the potential for adult-targeted campaigns to impact youth and suggest that Tips exposure may promote anti-smoking attitudes among youth.