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Background:Significant clinical similarities have been observed between the recently Described ‘Long-Haul’ COVID-19 (LHC) syndrome, Postural Orthostatic Tachycardia Syndrome (POTS) and Inappropriate Sinus Tachycardia (IST). Shared symptoms include light-headedness, palpitations, tremulousness, generalized weakness, blurred vision, chest pain, dyspnea, “brain-fog”, and fatigue. Ivabradine is a selective sinoatrial node blocker FDA-approved for management of tachycardia associated with stable angina and heart failure not fully managed by beta blockers. In our study we aim to identify risk factors underlying LHC, as well as the effectiveness of ivabradine in controlling heart rate dysregulations and POTS/IST related symptoms.Methods/Design:A detailed prospective phenotypic evaluation combined with multi-omic analysis of 200 LHC volunteers will be conducted to identify risk factors for autonomic dysfunction. A comparator group of 50 volunteers with documented COVID-19 but without LHC will be enrolled to better understand the risk factors for LHC and autonomic dysfunction. Those in the cohort who meet diagnostic criteria for POTS or IST will be included in a nested prospective, randomized, placebo-controlled trial to assess the impact of ivabradine on symptoms and heart rate, assessed non-invasively based on physiologic response and ambulatory electrocardiogram. Additionally, studies on catecholamine production, mast cell and basophil degranulation, inflammatory biomarkers, and indicators of metabolic dysfunction will be measured to potentially provide molecular classification and mechanistic insights.Discussion:Optimal therapies for dysautonomia, particularly associated with LHC, have yet to be defined. In the present study, ivabradine, one of numerous proposed interventions, will be systematically evaluated for therapeutic potential in LHC-associated POTS and IST. Additionally, this study will further refine the characteristics of the LHC-associated POTS/IST phenotype, genotype and transcriptional profile, including immunologic and multi-omic analysis of persistent immune activation and dysregulation. The study will also explore and identify potential endotheliopathy and abnormalities of the clotting cascade.Trial registration:ClinicalTrials.gov, ID:NCT05481177Registered on 29 July 2022.

We compared neutralizing antibody responses to BA.4/5, BQ.1.1, XBB, and XBB.1.5 Omicron SARS-CoV-2 variants after a bivalent or ancestral COVID-19 mRNA booster vaccine or post-vaccination infection. We found that the bivalent booster elicited moderately high antibody titers against BA.4/5 that were approximately two-fold higher against all Omicron variants than titers elicited by the monovalent booster. The bivalent booster elicited low but similar titers against both XBB and XBB.1.5 variants. These findings inform risk assessments for future COVID-19 vaccine recommendations and suggest that updated COVID-19 vaccines containing matched vaccine antigens to circulating divergent variants may be needed.

Background We sought to determine the frequency of asymptomatic SARS-CoV-2 infections, the BNT162b2 mRNA COVID 19 vaccine-related symptoms, and the correlates of immunity in post-vaccination breakthrough infections in a prospective cohort of healthcare workers. Methods We have been conducting a single-center, observational cohort study of healthcare workers. 271 participants were enrolled since August 25, 2020. Testing for SARS-CoV-2 spike (S)-specific IgG antibodies is conducted using a microsphere-based multiplex immunoassay interpolated against an internal standard curve for binding antibody (bAb) units (BAU) and has been performed on serum samples collected at monthly visits between September 2020 to August of 2021, and quarterly since then. Neutralizing antibody titers against wild-type (WT) virus are determined by microneutralization assays and against Delta and Omicron variants by lentiviral pseudovirus neutralization assays. For the first 6 months, participants completed a symptoms questionnaire every day they had any symptoms. Results 12 participants were diagnosed with SARS-CoV-2, with at least mild symptoms. Of 206 participants evaluated for adverse effects after 1st and 2nd vaccine doses, no relationship was observed between vaccine-associated symptom scores and antibody titers 1 month after the 2nd dose. Longitudinal studies demonstrate that anti-S IgG bAbs decrease from a geometric mean (GM) of 1929 BAU/mL at 1 month post-vaccination to a GM of 442 BAU/mL at 6 months post-vaccination (P< 0.001, n=187), and that boosting increases S-specific IgG BAU. While only 5 of 39 participants had detectable anti-Omicron neutralizing activity 1 month after 2 vaccinations, booster vaccination resulted in detectable neutralizing activity for all participants. Conclusion Asymptomatic infection is likely rare, that there is no relationship between vaccine-associated symptom severity and antibody titers 1 month after the 2nd vaccination, and that booster results in better protection against the Omicron variant. Ongoing studies are evaluating serological and cellular immune responses immediately prior to 38 breakthrough infections in an attempt to identify immune correlates of protection and will be reported at the conference. Disclosures John H. Powers, III, MD, Arrevus: Advisor/Consultant|Eicos: Advisor/Consultant|Evofem: Advisor/Consultant|Eyecheck: Advisor/Consultant|Gilead: Advisor/Consultant|GlaxoSmithKline: Advisor/Consultant|OPKO: Advisor/Consultant|Resolve: Advisor/Consultant|Romark: Advisor/Consultant|SpineBioPharma: Advisor/Consultant|UTIlity: Advisor/Consultant|Vir: Advisor/Consultant David Tribble, MD, DrPH, Astra Zeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response Simon Pollett, MBBS, Astra Zeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response Timothy Burgess, MD, MPH, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response.

SummaryThe rapid emergence of new SARS-CoV-2 variants challenges vaccination strategies. Here, we measured antigenic diversity among variants and interpreted neutralizing antibody responses following single and multiple exposures in longitudinal infection and vaccine cohorts. Antigenic cartography using primary infection antisera showed that BA.2, BA.4/BA.5, and BA.2.12.1 are distinct from BA.1 and closer to the Beta cluster. Three doses of an mRNA COVID-19 vaccine increased breadth to BA.1 more than to BA.4/BA.5 or BA.2.12.1. Omicron BA.1 post-vaccination infection elicited antibody landscapes characterized by broader immunity across antigenic space than three doses alone, although with less breadth than expected to BA.2.12.1 and BA.4/BA.5. Those with Omicron BA.1 infection after two or three vaccinations had similar neutralizing titer magnitude and antigenic breadth. Accounting for antigenic differences among variants of concern when interpreting neutralizing antibody titers aids understanding of complex patterns in humoral immunity and informs selection of future COVID-19 vaccine strains.

The rapid emergence of SARS-CoV-2 variants challenges vaccination strategies. Here, we collected 201 serum samples from persons with a single infection or multiple vaccine exposures, or both. We measured their neutralization titers against 15 natural variants and 7 variants with engineered spike mutations and analyzed antigenic diversity. Antigenic maps of primary infection sera showed that Omicron sublineages BA.2, BA.4/BA.5, and BA.2.12.1 are distinct from BA.1 and more similar to Beta/Gamma/Mu variants. Three mRNA COVID-19 vaccinations increased neutralization of BA.1 more than BA.4/BA.5 or BA.2.12.1. BA.1 post-vaccination infection elicited higher neutralization titers to all variants than three vaccinations alone, although with less neutralization to BA.2.12.1 and BA.4/BA.5. Those with BA.1 infection after two or three vaccinations had similar neutralization titer magnitude and antigenic recognition. Accounting for antigenic differences among variants when interpreting neutralization titers can aid the understanding of complex patterns in humoral immunity that informs the selection of future COVID-19 vaccine strains.

The rapid spread of the highly contagious Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) along with its high number of mutations in the spike gene has raised alarms about the effectiveness of current medical countermeasures. To address this concern, we measured the neutralization of the Omicron BA.1 variant pseudovirus by postvaccination serum samples after two and three immunizations with the Pfizer/BioNTech162b2 SARS-CoV-2 mRNA (Pfizer/BNT162b2) vaccine, convalescent serum samples from unvaccinated individuals infected by different variants, and clinical-stage therapeutic antibodies. We found that titers against the Omicron variant were low or undetectable after two immunizations and in many convalescent serum samples, regardless of the infecting variant. A booster vaccination increased titers more than 30-fold against Omicron to values comparable to those seen against the D614G variant after two immunizations. Neither age nor sex was associated with the differences in postvaccination antibody responses. We also evaluated 18 clinical-stage therapeutic antibody products and an antibody mimetic protein product obtained directly from the manufacturers. Five monoclonal antibodies, the antibody mimetic protein, three antibody cocktails, and two polyclonal antibody preparations retained measurable neutralization activity against Omicron with a varying degree of potency. Of these, only three retained potencies comparable to the D614G variant. Two therapeutic antibody cocktails in the tested panel that are authorized for emergency use in the United States did not neutralize Omicron. These findings underscore the potential benefit of mRNA vaccine boosters for protection against Omicron and the need for rapid development of antibody therapeutics that maintain potency against emerging variants.

Background The frequency of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is unclear and may be influenced by how symptoms are evaluated. In this study, we sought to determine the frequency of asymptomatic SARS-CoV-2 infections in a prospective cohort of health care workers (HCWs). Methods A prospective cohort of HCWs, confirmed negative for SARS-CoV-2 exposure upon enrollment, were evaluated for SARS-CoV-2 infection by monthly analysis of SARS-CoV-2 antibodies as well as referral for polymerase chain reaction testing whenever they exhibited symptoms of coronavirus disease 2019 (COVID-19). Participants completed the standardized and validated FLU-PRO Plus symptom questionnaire scoring viral respiratory disease symptom intensity and frequency at least twice monthly during baseline periods of health and each day they had any symptoms that were different from their baseline. Results Two hundred sixty-three participants were enrolled between August 25 and December 31, 2020. Through February 28, 2021, 12 participants were diagnosed with SARS-CoV-2 infection. Symptom analysis demonstrated that all 12 had at least mild symptoms of COVID-19, compared with baseline health, near or at time of infection. Conclusions These results suggest that asymptomatic SARS-CoV-2 infection in unvaccinated, immunocompetent adults is less common than previously reported. While infectious inoculum doses and patient factors may have played a role in the clinical manifestations of SARS-CoV-2 infections in this cohort, we suspect that the high rate of symptomatic disease was due primarily to participant attentiveness to symptoms and collection of symptoms in a standardized, prospective fashion. These results have implications for studies that estimate SARS-CoV-2 infection prevalence and for public health measures to control the spread of this virus.

The rapid spread of the highly contagious Omicron variant of SARS-CoV-2 along with its high number of mutations in the spike gene has raised alarm about the effectiveness of current medical countermeasures. To address this concern, we measured neutralizing antibodies against Omicron in three important settings: (1) post-vaccination sera after two and three immunizations with the Pfizer/BNT162b2 vaccine, (2) convalescent sera from unvaccinated individuals infected by different variants, and (3) clinical-stage therapeutic antibodies. Using a pseudovirus neutralization assay, we found that titers against Omicron were low or undetectable after two immunizations and in most convalescent sera. A booster vaccination significantly increased titers against Omicron to levels comparable to those seen against the ancestral (D614G) variant after two immunizations. Neither age nor sex were associated with differences in post-vaccination antibody responses. Only three of 24 therapeutic antibodies tested retained their full potency against Omicron and high-level resistance was seen against fifteen. These findings underscore the potential benefit of booster mRNA vaccines for protection against Omicron and the need for additional therapeutic antibodies that are more robust to highly mutated variants., One Sentence Summary: Third dose of Pfizer/BioNTech COVID-19 vaccine significantly boosts neutralizing antibodies to the Omicron variant compared to a second dose, while neutralization of Omicron by convalescent sera, two-dose vaccine-elicited sera, or therapeutic antibodies is variable and often low.

Antibodies against SARS-CoV-2 decay but persist six months post-vaccination, with lower levels of neutralizing titers against Delta than wild-type. Only 2 of 227 vaccinated healthcare workers experienced outpatient symptomatic breakthrough infections despite 59 of 227 exhibiting serological evidence of exposure to SARS-CoV-2 as defined by development of anti-nucleocapsid protein antibodies.

Background The relationship between postvaccination symptoms and strength of antibody responses is unclear. The goal of this study was to determine whether adverse effects caused by vaccination with the Pfizer/BioNTech BNT162b2 vaccine are associated with the magnitude of vaccine-induced antibody levels. Methods We conducted a single-center, observational cohort study consisting of generally healthy adult participants that were not severely immunocompromised, had no history of coronavirus disease 2019, and were seronegative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein before vaccination. Severity of vaccine-associated symptoms was obtained through participant-completed questionnaires. Testing for immunoglobulin G antibodies against SARS-CoV-2 spike protein and receptor-binding domain was conducted using microsphere-based multiplex immunoassays performed on serum samples collected at monthly visits. Neutralizing antibody titers were determined by microneutralization assays. Results Two hundred six participants were evaluated (69.4% female, median age 41.5 years old). We found no correlation between vaccine-associated symptom severity scores and vaccine-induced antibody titers 1 month after vaccination. We also observed that (1) postvaccination symptoms were inversely correlated with age and weight and more common in women, (2) systemic symptoms were more frequent after the second vaccination, (3) high symptom scores after first vaccination were predictive of high symptom scores after second vaccination, and (4) older age was associated with lower titers. Conclusions Lack of postvaccination symptoms after receipt of the BNT162b2 vaccine does not equate to lack of vaccine-induced antibodies 1 month after vaccination., We found no correlation between BNT162b2-associated symptom severity and vaccine-induced antibody titers 1 month after vaccination. Adverse effects inversely correlated with age and weight, whereas symptom severity after first vaccination was predictive of that after second vaccination.

Background The Prospective Assessment of SARS-CoV-2 Seroconversion (PASS) study is following over 200 healthcare workers who have received the Pfizer-BioNTech BNT162b2 COVID-19 mRNA vaccine. A major aim of the study is to determine whether baseline antibody titers against the seasonal human coronaviruses are associated with altered levels of vaccine-induced antibody responses to SARS-CoV-2. Methods Serial serum samples obtained pre-vaccination and 1 month after the second dose were tested for IgG antibodies against the full pre-fusion spike protein and the receptor binding domain (RBD) of SARS-CoV-2, as well as the full pre-fusion spike proteins of OC43, HKU1, 229E, and NL63. Antibodies were measured using highly sensitive and specific multiplex assays based on Luminex-xMAP technology. Results Preliminary analyses of the first 103 subjects in whom we have 1 month post-vaccination serum demonstrate development of high IgG geometric mean titers (GMT) to both the full spike protein (GMT: 13,685, 12,014-15,589, 95% CI) and the RBD (GMT: 19,448, 17,264-21,908, 95% CI) of SARS-CoV-2 after the 2nd vaccine dose. Preliminary analysis demonstrates no association between baseline antibody titers against spike protein of OC43 and antibody titers against SARS-CoV-2 spike protein (Pearson’s r-value= 0.13, P-value= 0.21) or RBD (Pearson’s r-value= 0.09, P-value= 0.36) one month after vaccination. Future analyses will evaluate whether there is an association with baseline seasonal coronavirus antibody titers and either SARS-CoV-2 neutralization titers or anti-SARS-CoV-2 spike protein titers at 6 months after vaccination. Conclusion These preliminary results suggest that baseline antibody responses to seasonal coronaviruses neither boost nor impede SARS-CoV-2 vaccine-induced antibody responses. Longitudinal sampling will enable assessment of vaccine durability and determination of whether baseline seasonal coronavirus antibody levels are associated with altered duration of detectable COVID-19 vaccine-induced antibody responses. Disclosures Simon Pollett, MBBS, Astra Zeneca (Other Financial or Material Support, HJF, in support of USU IDCRP, funded under a CRADA to augment the conduct of an unrelated Phase III COVID-19 vaccine trial sponsored by AstraZeneca as part of USG response (unrelated work)) David Tribble, M.D., DrPH, Astra Zeneca (Other Financial or Material Support, HJF, in support of USU IDCRP, funded under a CRADA to augment the conduct of an unrelated Phase III COVID-19 vaccine trial sponsored by AstraZeneca as part of USG response (unrelated work))

Systematic Lupus Erythematosus (SLE) is an autoimmune syndrome of unclear etiology. While T and B cell abnormalities contribute to disease pathogenesis, recent work suggests that inflammatory M1-like macrophages also play a role. Previous work showed that the TLR2/1 agonist PAM3CSK4 (PAM3) could stimulate normal human monocytes to preferentially differentiate into immunosuppressive M2-like rather than inflammatory M1-like macrophages. This raised the possibility of PAM3 being used to normalize the M1:M2 ratio in SLE. Consistent with that possibility, monocytes from lupus patients differentiated into M2-like macrophages when treated with PAM3 in vitro. Furthermore, lupus-prone NZB x NZW F1 mice responded similarly to weekly PAM3 treatment. Normalization of the M2 macrophage frequency was associated with delayed disease progression, decreased autoantibody and inflammatory cytokine synthesis, reduced proteinuria and prolonged survival in NZB x NZW F1 mice. The ability of PAM3 to bias monocyte differentiation in favor of immunosuppressive macrophages may represent a novel approach to the therapy of SLE.

International audience; Endoparasitoid wasps, which lay eggs inside the bodies of other insects, use various strategies to protect their offspring from the host immune response. The hymenopteran species of the genus Leptopilina, parasites of Drosophila, rely on the injection of a venom which contains proteins and peculiar vesicles (hereafter venosomes). We show here that the injection of purified L. boulardi venosomes is sufficient to impair the function of the Drosophila melanogaster lamellocytes, a hemocyte type specialized in the defense against wasp eggs, and thus the parasitic success of the wasp. These venosomes seem to have a unique extracellular biogenesis in the wasp venom apparatus where they acquire specific secreted proteins/virulence factors and act as a transport system to deliver these compounds into host lamellocytes. The level of venosomes entry into lamellocytes of different Drosophila species was correlated with the rate of parasitism success of the wasp, suggesting that this venosome-cell interaction may represent a new evolutionary level of host-parasitoid specificity.

Systematic Lupus Erythematosus (SLE) is an autoimmune syndrome of unclear etiology. While T and B cell abnormalities contribute to disease pathogenesis, recent work suggests that inflammatory M1-like macrophages also play a role. Previous work showed that the TLR2/1 agonist PAM3CSK4 (PAM3) could stimulate normal human monocytes to preferentially differentiate into immunosuppressive M2-like rather than inflammatory M1-like macrophages. This raised the possibility of PAM3 being used to normalize the M1:M2 ratio in SLE. Consistent with that possibility, monocytes from lupus patients differentiated into M2-like macrophages when treated with PAM3 in vitro. Furthermore, lupus-prone NZB x NZW F1 mice responded similarly to weekly PAM3 treatment. Normalization of the M2 macrophage frequency was associated with delayed disease progression, decreased autoantibody and inflammatory cytokine synthesis, reduced proteinuria and prolonged survival in NZB x NZW F1 mice. The ability of PAM3 to bias monocyte differentiation in favor of immunosuppressive macrophages may represent a novel approach to the therapy of SLE.

Systematic Lupus Erythematosus (SLE) is an autoimmune disease characterized by the overproduction of autoantibodies and the chronic inflammation of multiple organs. Early studies suggested that T and/or B cell abnormalities were critical to disease pathogenesis in lupus patients. More recent work shows that abnormalities in the innate immunity play a contributory if not central role. In that context, we find that SLE patients have significantly more CD14lowCD16+ monocytes compared to healthy controls.CD14lowCD16+ monocytes are a subset known as non-classical monocytes and display inflammatory characteristics upon activation. The frequency of inflammatory macrophages correlates with disease severity and is associated with reduced clearance of apoptotic cells and the overproduction of inflammatory cytokines. We previously found that the TLR2/1 agonist PAM3CSK4 (PAM3) can inhibit the generation of M1- while promoting the generation of immunosuppressive M2-like macrophages. This work examines whether PAM3 can shift the M1:M2 macrophage ratio to restore balance in lupus patients. Even though phenotypically, PAM3 did not seem to induce as many as CD163+ (a functional marker of M2) macrophages like M-CSF did, there was no significant difference in the endocytosis ability of the CD163+ macrophages induced by PAM3 compared M-CSF induced ones. The in vivo activity of PAM3 was investigated in the NZB/W murine model of lupus. Preliminary results indicate that, PAM3 injection increases the survival and decreases proteinuria in mice sera. These findings suggest that PAM3 may promote the polarization of SLE monocytes into immunosuppressive macrophages and thus could represent a novel approach to the therapy of this autoimmune disease.

Introduction TLR7/8 agonist (3M-052) and TLR9 agonist (CpG ODN) both trigger innate immune responses supporting the induction of tumor-specific immunity. Previous studies showed that this specific combination of TLR agonists synergistically promoted the elimination of large established tumors (>500 mm3). This effect was optimized when delivered directly into the tumor, leading to a conversion from immunosuppressive to inflammatory milieu. The current work explores the effect of a combination of a localized TLR agonists therapy and a systemic chemotherapy on lung metastases. Methods 66Cl4-luc cells (a luciferase-expressing variant of the 4T1 murine mammary carcinoma line) were orthotopically implanted into the fourth mammary fat pad of syngeneic Balb/c mice. The combination therapy was initiated when the primary tumor exceeded 300 mm3 and pulmonary metastases were present. Results Treatment delivered into both the primary tumor and the lungs, when associated with systemic chemotherapy significantly reduced tumor growth and prolonged survival. Discussion The combined effect of the two TLR agonists was further enhanced when associated with classic chemotherapy, providing a significant decrease of tumor growth at both sites. These results provide new leads to explore when considering lung metastases treatment.

Background: The present study was planned to investigate the therapeutic actions of 1-tetradecanol complex (1-TDC), a novel monounsaturated fatty acid mixture, in established periodontitis in rabbits. Methods: Periodontitis was initiated in 18 New Zealand White rabbits using ligatures around mandibular second premolars, followed by topical Porphyromonas gingivalis application (10 9 colony forming units). After 6 weeks of disease induction (phase 1), three animals were sacrificed to assess the established periodontitis level. P. gingivalis application was discontinued, and the remaining 15 animals continued with topical treatment of 1-TDC (100 mg/ml; n = 5) or placebo (n = 5) or no treatment (n = 5) for an additional 6 weeks (phase 2). Mandibular block sections obtained after euthanasia were decalcified and embedded in paraffin. In addition to the macroscopic analyses, hematoxylin and eosin–stained sections were used to study cellular inflammatory infiltrate and quantitative histomorphometry. Tartrate-resistant acid phosphatase and osteocalcin were used to identify osteoclastic and osteoblastic activity, respectively. Results: P. gingivalis application resulted in periodontal disease with gingival inflammation and bone loss (30% compared to baseline) at 6 weeks. Treatment with 1-TDC stopped the progression of the disease and resulted in a significant reduction in the macroscopic periodontal inflammation, attachment, and bone loss (10.1% – 1.8%), whereas periodontal disease progressed in the untreated and placebo groups (P

Resolvin E1 (RvE1) is a potent proresolving mediator of inflammation derived from omega-3 eicosapentaenoic acid that acts locally to stop leukocyte recruitment and promote resolution. RvE1 displays potent counter-regulatory and tissue-protective actions in vitro and in vivo. Periodontal disease is a local inflammatory disease initiated by bacteria characterized by neutrophil-mediated tissue injury followed by development of a chronic immune lesion. In this study, we report the treatment of established periodontitis using RvE1 as a monotherapy in rabbits compared with structurally related lipids PGE2 and leukotriene B4. PGE2 and leukotriene B4 each enhanced development of periodontitis and worsened the severity of disease. Promotion of resolution of inflammation as a therapeutic target with RvE1 resulted in complete restoration of the local lesion, and reduction in the systemic inflammatory markers C-reactive protein and IL-1β. This report is the first to show that resolution of inflammation by a naturally occurring endogenous lipid mediator results in complete regeneration of pathologically lost tissues, including bone.

The TLR7/8 agonist 3M-052 and the TLR9 agonist CpG ODN both trigger innate immune responses that support the induction of tumor-specific immunity. Previous studies showed that intra-tumoral delivery of this agonist combination was synergistic and led to the eradication of large primary tumors and the establishment of long-term protective immunity in murine tumor models. We explored the effect of delivering 3M-052 plus CpG ODN to the lungs of mice bearing breast-derived lung metastases. 66Cl4-Luc cells (a luciferase-expressing variant of the 4T1 murine mammary carcinoma) were orthotopically implanted in the fourth mammary fat pad of Balb/c mice. Progression of the primary tumor and lung metastases was monitored by bioluminescence. TLR agonist treatment by intratracheal instillation was initiated after mets were detected in the lungs. Results show that intra-pulmonary treatment with the combination of TLR7/8 and TLR9 agonists slowed the growth of the lung metastases compared to either agonist alone. This treatment decreased pulmonary tumor burden and significantly prolonged survival when compared to control (untreated) animals. In contrast, pulmonary therapy had no significant effect on the primary tumor. Results from ongoing studies examining the effect of higher/more frequent lung delivery combined with direct treatment of the primary tumor will be presented.

SUMMArY OBJECTIvES: Piezocision is a novel, minimally invasive technique combining micro-incisions and decortications made by a piezotome in order to enhance the rate of orthodontic tooth movement. The combined technique allows simultaneous hard and/or soft tissue grafting via selective tunnelling to correct gingival recessions or bone deficiencies. The present study was designed to evaluate the effects of Piezocision on bone with or without tooth movement on a rat model. MATErIAlS AND METHODS: Ninety-four Sprague–Dawley rats were divided into four groups: no treatment (n = 3), TM (tooth movement alone; n = 21), PS (Piezocision alone; n = 35), and PS + TM (Piezocision and tooth movement; n = 35). In each group, seven time points were studied: 1, 3, 7, 14, 28, 42, and 56 days. After sacrifice, the maxillae were removed, defleshed, stained with haematoxylin and eosin for morphometric analyses and tartrate-resistant acid phosphatase for osteoclastic activity. rESUlTS: Three days after the surgery, the bone content decreased significantly in the PS and PS + TM groups compared to baseline (P < 0.01) and the TM group (P < 0.05). This trend continued until Day 28 and was particularly evident in the PS + TM group. At Day 56, alveolar bone returned to its baseline levels in all groups. Osteoclastic activity followed similar change pattern found in the amount of bone, suggesting a strong role for the coupling of the resorptive and formative turnover of the bone. Osteoclastic activity increased as soon as Day 1 in the PS (29.0 ± 3.0, P