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Articles 1 - 24 of 24
Full-Text Articles in Engineering
Developing An Immunomodulatory Strategy Using Biophysical Cues To Modulate Macrophage Phenotype For Fracture Healing And Bone Regeneration, Harshini Suresh Kumar
Developing An Immunomodulatory Strategy Using Biophysical Cues To Modulate Macrophage Phenotype For Fracture Healing And Bone Regeneration, Harshini Suresh Kumar
Theses and Dissertations--Biomedical Engineering
Chronic inflammation is a major cause of the pathogenesis of musculoskeletal diseases such as fragility, fracture, and nonunion. Studies have shown that modulating the immune phenotype of macrophages from proinflammatory to pro-healing can heal recalcitrant bone defects. Current therapeutic strategies predominantly apply biochemical cues, which often lack target specificity, and controlling their release kinetics in vivo is challenging spatially and temporally. We have developed a magnetic iron-oxide nanocomplexes (MNC)-based therapy for resolving chronic inflammation in the context of promoting fracture healing. Here, we show that MNC internalized macrophages, when coupled with an external magnetic field, can exert an intracellular magnetic …
Surface Antibody Changes Protein Corona Both In Human And Mouse Serum But Not Final Opsonization And Elimination Of Targeted Polymeric Nanoparticles, Sara Capolla, Federico Colombo, Luca De Maso, Prisca Mauro, Paolo Bertoncin, Thilo Kähne, Alexander Engler, Luis Núñez, Gustavo Larsen, Et Al.
Surface Antibody Changes Protein Corona Both In Human And Mouse Serum But Not Final Opsonization And Elimination Of Targeted Polymeric Nanoparticles, Sara Capolla, Federico Colombo, Luca De Maso, Prisca Mauro, Paolo Bertoncin, Thilo Kähne, Alexander Engler, Luis Núñez, Gustavo Larsen, Et Al.
Department of Chemical and Biomolecular Engineering: Faculty Publications
Background: Nanoparticles represent one of the most important innovations in the medical field. Among nanocarriers, polymeric nanoparticles (PNPs) attracted much attention due to their biodegradability, biocompatibility, and capacity to increase efficacy and safety of encapsulated drugs. Another important improvement in the use of nanoparticles as delivery systems is the conjugation of a targeting agent that enables the nanoparticles to accumulate in a specific tissue. Despite these advantages, the clinical translation of therapeutic approaches based on nanoparticles is prevented by their interactions with blood proteins. In fact, the so-formed protein corona (PC) drastically alters the biological identity of the particles. Adsorbed …
Interactions Of Carboxylated Nanodiamonds With Mouse Macrophages Cell Line And Primary Cells, Maisoun Bani-Hani, Stephen J. Beebe, Michael W. Stacey, Christopher Osgood
Interactions Of Carboxylated Nanodiamonds With Mouse Macrophages Cell Line And Primary Cells, Maisoun Bani-Hani, Stephen J. Beebe, Michael W. Stacey, Christopher Osgood
Bioelectrics Publications
Nanodiamonds (ND) have attracted significant interest for their use in several biomedical applications. These applications can be very useful if the safety and compatibility of ND are proven. We assessed the effects of ND (100 nm, Carboxylated) on primary macrophages and a macrophage-like cell line and found that these particles are not toxic to these cells at lower concentrations but may interfere with cell functions and differentiation. Internalization of ND by these cells in a time- and dose-dependent manner was mostly via phagocytosis and clathrin-dependent endocytosis and localized to the cytoplasm but not into the nucleus. No significant induction of …
Elucidating Mammalian Cellular Responses To The Uptake Of Nanoparticles (Nps), Pathogens, And Lipoproteins: Similarities And Differences, Monireh Asoudeh
Elucidating Mammalian Cellular Responses To The Uptake Of Nanoparticles (Nps), Pathogens, And Lipoproteins: Similarities And Differences, Monireh Asoudeh
Doctoral Dissertations
Soft poly-ethylene-glycol (PEG)-based soft nanoparticles (NPs) including cylindrical (CNPs) micelles, spherical (SNPs) micelles, and lipid bilayer vesicles (LNPs) are thought to be treated as foreign objects by mammalian phagocytes. If this hypothesis is true, NPs should trigger a proinflammatory, autophagic phenotype that is similar to the one seen when macrophages phagocytose pathogens or when macrophage surface expressed proteins bind pathogen surface factors such as lipopolysaccharide (LPS). Here, we show that macrophage responses to the above NPs are almost completely unique from those triggered by group A streptococcus (GAS) pathogens (JRS4 cells) and LPS. Instead, macrophages treat these soft NPs more …
Effects Of Surface Topography On Macrophages And Bacterial Cells, Joseph Carnicelli
Effects Of Surface Topography On Macrophages And Bacterial Cells, Joseph Carnicelli
Theses - ALL
An association has been found between the texture of breast implants and anaplastic large cell lymphoma, which led to some textured implants to be withdrawn from the market in 2019. There is evidence that these cancers are associated with the harboring of bacteria on the surfaces of the textured implants. It is possible that specific topographic features hinder the removal of attached bacteria by inhibiting macrophage phagocytosis or promoting biofilm formation. Here we examine how bacteria and macrophages interact with recessive surface topographies as analogs to the surfaces seen on textured breast implants. Changes in bacteria morphology were observed among …
Impact Of Primary Myoblasts On Macrophage Polarization In-Vitro, Olivia Welch
Impact Of Primary Myoblasts On Macrophage Polarization In-Vitro, Olivia Welch
Master's Theses
Peripheral artery disease (PAD) is characterized by the development of atherosclerotic plaques on arterial walls, leading to the narrowing of blood vessels, resulting in ischemia in the downstream tissue. In the United States, 12% of the adult population is affected by PAD and its related symptoms. Current surgical revascularization techniques can be effective in part of the patient population, but there is a need for other options. Alternatively, collateral blood vessels, or natural bypass arteries, enlarge to increase blood flow to the ischemic tissue in a process called arteriogenesis, which has been studied as a therapeutic option. Cell-based therapies, such …
Effects Of Il-10 On Local Cell Populations And Functional Recovery Following Vml Injury, Zain Blackwell
Effects Of Il-10 On Local Cell Populations And Functional Recovery Following Vml Injury, Zain Blackwell
Biomedical Engineering Undergraduate Honors Theses
Volumetric muscle loss (VML) injuries are prevalent in both military personnel suffering from battlefield related incidents, and civilians following severe motor accidents. Despite its prevalence, VML has no pro-regenerative clinical treatments in place to recover some of the functional capabilities of the damaged muscle. Free flap grafting, debridement of damaged tissue, and physical therapy are the only clinical standards available that offer little functional recovery benefits, even after years of consistent treatment. In this study, anti-inflammatory cytokine interleukin-10 in conjunction with autologous minced muscle was assessed as a possible treatment for VML injuries and its influences on cellular behavior within …
Defining The Innate Immune Responses For Sars-Cov-2-Human Macrophage Interactions, Mai M. Abdelmoaty, Pravin Yeapuri, Jatin Machhi, Katherine E. Olson, Farah Shahjin, Vikas Kumar, You Zhou, Jingjing Liang, Kabita Pandey, Arpan Acharya, Siddappa N. Byrareddy, R. Lee Mosley, Howard E. Gendelman
Defining The Innate Immune Responses For Sars-Cov-2-Human Macrophage Interactions, Mai M. Abdelmoaty, Pravin Yeapuri, Jatin Machhi, Katherine E. Olson, Farah Shahjin, Vikas Kumar, You Zhou, Jingjing Liang, Kabita Pandey, Arpan Acharya, Siddappa N. Byrareddy, R. Lee Mosley, Howard E. Gendelman
Nebraska Center for Biotechnology: Faculty and Staff Publications
Host innate immune response follows severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and it is the driver of the acute respiratory distress syndrome (ARDS) amongst other inflammatory end-organ morbidities. Such life-threatening coronavirus disease 2019 (COVID-19) is heralded by virus-induced activation of mononuclear phagocytes (MPs; monocytes, macrophages, and dendritic cells). MPs play substantial roles in aberrant immune secretory activities affecting profound systemic inflammation and end-organ malfunctions. All follow the presence of persistent viral components and virions without evidence of viral replication. To elucidate SARS-CoV- 2-MP interactions we investigated transcriptomic and proteomic profiles of human monocyte-derived macrophages. While expression of the …
High-Spatial-Resolution Transcriptomic Map Of The Mouse Lymph Node Microenvironment Using Deterministic Barcoding, Archibald Enninful, Yang Liu, Rong Fan
High-Spatial-Resolution Transcriptomic Map Of The Mouse Lymph Node Microenvironment Using Deterministic Barcoding, Archibald Enninful, Yang Liu, Rong Fan
The Yale Undergraduate Research Journal
Spatial transcriptomics is an emerging approach which characterizes gene expression profiles for a more nuanced understanding of biological processes at a tissue level. This offers significant advantages over traditional omics which require the digestion of tissues and subsequent isolation of cells, during which the spatial information is completely lost. Lymph nodes are an integral part of the immune system and an in-depth analysis of its spatial organization will provide useful insights which can be applicable in the development of novel immunotherapies. In this study, the mouse lymph node is characterized using the newly developed microfluidic-based approach, Deterministic Barcoding in Tissue …
Disentangling Glial Diversity In Peripheral Nerves At Single Nuclei Resolution, Aldrin Kay Yuen Yim
Disentangling Glial Diversity In Peripheral Nerves At Single Nuclei Resolution, Aldrin Kay Yuen Yim
Arts & Sciences Electronic Theses and Dissertations
The ability to discern gene expression at single cell level is revolutionizing our understanding of both basic biology and human health. Peripheral nerves are essential communicators between the outside world and the CNS, as evidenced by the devastating effects of diseases that disrupt them, such as ALS, Charcot-Marie-Tooth Syndrome and diabetic neuropathy. Understanding peripheral nerve dysfunction at a mechanistic level is of considerable interest due to the increasing prevalence and associated patient care costs of these disorders. Although most research of the peripheral nerve has focused on glial-axonal interactions, the important contributions of other cell types besides Schwann cells, such …
Pilot Study Exploring The Effect Of Targeted Cox-2 Inhibition In Macrophages Responding To Neuronal Injury; Promoting Enhanced Axonal Regeneration, Alyssa Brauckmann
Pilot Study Exploring The Effect Of Targeted Cox-2 Inhibition In Macrophages Responding To Neuronal Injury; Promoting Enhanced Axonal Regeneration, Alyssa Brauckmann
Electronic Theses and Dissertations
Celecoxib nanoemulsion (CXB-NE) has been developed as a macrophage targeted analgesics by Dr. Janjic and her team at Duquesne University, (Janjic et al, 2018; Liu et al, 2020; Saleem et al, 2019b; Vasudeva et al, 2014). The CXB-NE nanoemulsion carrying a Nonsteroidal Anti-inflammatory (NSAID) inhibitor of COX-2 activity result in a reduction in PGE2 expression in macrophages. Using CXB-NE in rats that have peripheral nerve injury constricting the sciatic nerve relieves hypersensitivity, a pain-like behavior. The treatment also decreases inflammation associated with this chronic constriction injury (Janjic et al, 2018; Saleem et al, 2019b; Stevens et al, 2019). In this …
Cardiac Regenerative Medicine: Insights From Healthy And Diseased Engineered Tissues, Pamela Grace Hitscherich
Cardiac Regenerative Medicine: Insights From Healthy And Diseased Engineered Tissues, Pamela Grace Hitscherich
Dissertations
Cardiovascular disease remains the leading cause of mortality in the United States. Current tissue engineering approaches have fallen short of promoting fully functional cardiovascular cells and the post-myocardial infarction microenvironment is still not well understood. These gaps in knowledge are addressed in this dissertation through the development of in vitro engineered cardiac tissues using electroactive materials to enhance the differentiation of pluripotent stem cell derived cardiomyocytes and through the development of in vitro myocardial inflammation models dedicated to understanding cardiomyocytes and macrophages interactions.
Specifically, piezoelectric poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) supports the attachment and survival of mouse embryonic stem cell derived …
Prevalence Of Infection-Competent Serogroup 6 Legionella Pneumophila Within Premise Plumbing In Southeast Michigan, Brenda G. Byrne, Sarah Mccolm, Shawn P. Mcelmurry, Paul E. Kilgore, Joanne Sobeck, Rick Sadler, Nancy G. Love, Michele S. Swanson
Prevalence Of Infection-Competent Serogroup 6 Legionella Pneumophila Within Premise Plumbing In Southeast Michigan, Brenda G. Byrne, Sarah Mccolm, Shawn P. Mcelmurry, Paul E. Kilgore, Joanne Sobeck, Rick Sadler, Nancy G. Love, Michele S. Swanson
Department of Pharmacy Practice
Coinciding with major changes to its municipal water system, Flint, MI, endured Legionnaires’ disease outbreaks in 2014 and 2015. By sampling premise plumbing in Flint in the fall of 2016, we found that 12% of homes harbored legionellae, a frequency similar to that in residences in neighboring areas. To evaluate the genetic diversity of Legionella pneumophila in Southeast Michigan, we determined the sequence type (ST) and serogroup (SG) of the 18 residential isolates from Flint and Detroit, MI, and the 33 clinical isolates submitted by hospitals in three area counties in 2013 to 2016. Common to one environmental and four …
Biomaterials Approaches For Utilizing The Regenerative Potential Of The Peripheral Nerve Injury Microenvironment, Melissa Renee Wrobel
Biomaterials Approaches For Utilizing The Regenerative Potential Of The Peripheral Nerve Injury Microenvironment, Melissa Renee Wrobel
Wayne State University Dissertations
Clinically available treatments are insufficient to achieve full functional recovery in large (>3cm) peripheral nerve injuries (PNI). The objectives in this thesis were 1) to study often overlooked elements of intrinsic PNI repair including release of inhibitory CSPGs and post-injury responses of inflammatory macrophages and dedifferentiated Schwann cells; 2) to create biomaterial scaf-folds featuring topographical and adhesive cues to enhance neurite outgrowth; and 3) to test the ability of those cues to direct macrophages and Schwann cells towards a pro-regenerative phe-notype. It is hypothesized that recapitulating the positive and negative cues of the PNI microenvi-ronment can better improve regeneration. …
Methamphetamine Administration Targets Multiple Immune Subsets And Induces Phenotypic Alterations Suggestive Of Immunosuppression., Robert Z. Harms, Brenda M. Morsey, Craig W. Boyer, Howard S. Fox, Nora E. Sarvetnick
Methamphetamine Administration Targets Multiple Immune Subsets And Induces Phenotypic Alterations Suggestive Of Immunosuppression., Robert Z. Harms, Brenda M. Morsey, Craig W. Boyer, Howard S. Fox, Nora E. Sarvetnick
Journal Articles: Regenerative Medicine
Methamphetamine (Meth) is a widely abused stimulant and its users are at increased risk for multiple infectious diseases. To determine the impact of meth on the immune system, we utilized a murine model that simulates the process of meth consumption in a typical addict. Our phenotypic analysis of leukocytes from this dose escalation model revealed that meth affected key immune subsets. Meth administration led to a decrease in abundance of natural killer (NK) cells and the remaining NK cells possessed a phenotype suggesting reduced responsiveness. Dendritic cells (DCs) and Gr-1(high) monocytes/macrophages were also decreased in abundance while Gr-1(low) monocytes/macrophages appear …
Regeneration Of Electrospun Bioresorbable Vascular Grafts: A Phenomenon Associated With Vascular Graft Properties And Macrophage Phenotypes (M1/M2), Koyal Garg
Theses and Dissertations
Macrophages (MФ) and mast cells are important cell types in the context of tissue remodeling and regeneration. Mast cells participate in the early stages of wound healing and modulate the acute inflammatory responses to biomaterials. Mast cells can secrete a myriad of different cytokines by the process of degranulation; the process of regulated secretion in which preformed contents stored in their granules are rapidly released by exocytosis. Some of these cytokines such as IL-4, IL-13 and TNF-α can modulate the MФ phenotype. Macrophages (MΦ) are innate immune cells, crucial for tissue homeostasis, presentation of foreign and self-antigens following infection/injury, pathogen …
The Yin And Yang Actions Of North American Ginseng Root In Modulating The Immune Function Of Macrophages, Chike Godwin Azike, Paul Abrahams Charpentier, Jirui Hou, Hua Pei, Edmund Man King Lui
The Yin And Yang Actions Of North American Ginseng Root In Modulating The Immune Function Of Macrophages, Chike Godwin Azike, Paul Abrahams Charpentier, Jirui Hou, Hua Pei, Edmund Man King Lui
Physiology and Pharmacology Publications
BACKGROUND: Immuno-modulatory effects of ginseng, including both immuno-stimulatory and immuno-suppressive effects, have been widely reported. This study aims to determine whether the paradoxical immuno-modulatory effect is related to unique phytochemical profiles of different North American (NA) ginseng, namely aqueous (AQ) and alcoholic (ALC) extracts.
METHODS: AQ and ALC extracts were prepared and their immuno-bioactivity were studied in vitro in murine macrophages (Raw 264.7) through measuring the direct stimulatory production of pro-inflammatory mediator and cytokines as well as the suppression of lipopolysaccharide (LPS)-stimulatory response by the two extracts. Gel permeation chromatography was used to fractionate and isolate phytochemicals for characterization of …
The Yin And Yang Actions Of North American Ginseng Root In Modulating The Immune Function Of Macrophages, Chike Azike, Paul Charpentier, Jirui Hou, Hua Pei, Edmund Lui
The Yin And Yang Actions Of North American Ginseng Root In Modulating The Immune Function Of Macrophages, Chike Azike, Paul Charpentier, Jirui Hou, Hua Pei, Edmund Lui
Edmund M. K. Lui
BACKGROUND: Immuno-modulatory effects of ginseng, including both immuno-stimulatory and immuno-suppressive effects, have been widely reported. This study aims to determine whether the paradoxical immuno-modulatory effect is related to unique phytochemical profiles of different North American (NA) ginseng, namely aqueous (AQ) and alcoholic (ALC) extracts.
METHODS: AQ and ALC extracts were prepared and their immuno-bioactivity were studied in vitro in murine macrophages (Raw 264.7) through measuring the direct stimulatory production of pro-inflammatory mediator and cytokines as well as the suppression of lipopolysaccharide (LPS)-stimulatory response by the two extracts. Gel permeation chromatography was used to fractionate and isolate phytochemicals for characterization of …
Macrophages Loaded With Gold Nanoshells For Photothermal Ablation Of Glioma: An In Vitro Model, Amani Riad Makkouk
Macrophages Loaded With Gold Nanoshells For Photothermal Ablation Of Glioma: An In Vitro Model, Amani Riad Makkouk
UNLV Theses, Dissertations, Professional Papers, and Capstones
The current median survival of patients with glioblastoma multiforme (GBM), the most common type of glioma, remains at 14.6 months despite multimodal treatments (surgery, radiotherapy and chemotherapy). This research aims to study the feasibility of photothermal ablation of glioma using gold nanoshells that are heated upon laser irradiation at their resonance wavelength. The novelty of our approach lies in improving nanoshell tumor delivery by loading them in macrophages, which are known to be recruited to gliomas via tumor-released chemoattractive agents. Ferumoxides, superparamagnetic iron oxide (SPIO) nanoparticles, are needed as an additional macrophage load in order to visualize macrophage accumulation in …
Angiogenic Potential Of Human Macrophages On Electrospun Bioresorbable Vascular Grafts, Koyal Garg
Angiogenic Potential Of Human Macrophages On Electrospun Bioresorbable Vascular Grafts, Koyal Garg
Theses and Dissertations
The aim of this study was to investigate macrophage interactions with electrospun scaffolds and quantify the expression of vital angiogenic growth factors in vitro. This study will further help in evaluating the potential of these electrospun constructs as vascular grafts for tissue repair and regeneration in situ. Human peripheral blood macrophages were seeded in serum free media on electrospun (10 mm) discs of polydioxanone (PDO), elastin and PDO:elastin blends (50:50, 70:30 and 90:10). The growth factor secretion was analyzed by ELISA. Macrophages produced high levels of vascular endothelial growth factor (VEGF) and acidic fibroblast growth factor (aFGF). Transforming growth factor …
In Vitro Toxicity Of Aluminum Nanoparticles In Rat Alveolar Macrophages, Andrew J. Wagner
In Vitro Toxicity Of Aluminum Nanoparticles In Rat Alveolar Macrophages, Andrew J. Wagner
Theses and Dissertations
Nanomaterials, which are by definition in the 1 - 100 nanometer range, have numerous possible benefits to society, but currently there is a lack of data that characterizes these materials effects on human health and environment. In general nanomaterials are of interest to the Air Force because of their applications in electronics, sensors, munitions and energetic/reactive systems. Nanoparticles such as aluminum have been considered for enhancing propulsion in solid rocket fuel. To date, only a few studies have looked at the toxicological effects of direct exposure to nanoparticles, none with aluminum. It is important to increase the understanding of the …
Macrophage Response To Polymethylmethacrylate Particles, Stephen M. Horowtiz
Macrophage Response To Polymethylmethacrylate Particles, Stephen M. Horowtiz
Cells and Materials
This paper reviews studies performed by this laboratory involving the macrophage response to implant particles. Through the development of a tissue culture model, we have studied the events which occur following macrophage phagocytosis of bone cement particles, the released mediators and cell interactions which may ultimately lead to bone resorption, and the inhibition of this process with the use of pharmaceutical agents. This is divided into the following sections: Histologic response of macrophages to cement particles I toxicity I and mediator release, the effects of particle size and composition on mediator release by macrophages, macrophage I osteoblast interactions, macrophage I …
Biodegradation Of Synthetic Biphasic Calcium Phosphate And Biological Calcified Substratum By Cells Of Hemopoietic Origin, A. Soueidan, O. I. Gan, J. M. Bouler, F. Gouin, G. Daculsi
Biodegradation Of Synthetic Biphasic Calcium Phosphate And Biological Calcified Substratum By Cells Of Hemopoietic Origin, A. Soueidan, O. I. Gan, J. M. Bouler, F. Gouin, G. Daculsi
Cells and Materials
Different types of osteoclastic cells (authentic osteoclasit from human giant cell tumor and bone marrow of newborn rats; newly-formed osteoclasts from adult rat bone marrow), giant multinucleated cells and macrophages were studied for their effect on synthetic and natural mineralized substrata. Biphasic calcium phosphate ceramic consisted of hydroxyapatite and beta tricalcium phosphate was chosen for in vitro experiments, and dentine served as a positive control for cell resorbing activity . Our results show the limited capacity of authentic and newly-formed osteoclasts to resorb synthetic ceramic as compared to that of natural substrata. In vitro cell-mediated biodegradation included also modifications of …
Nitric Oxide Production: A Mechanism For Inhibition Of Chlamydia Trachomatis Replication, Bojun Chen
Nitric Oxide Production: A Mechanism For Inhibition Of Chlamydia Trachomatis Replication, Bojun Chen
Electronic Theses and Dissertations
Chlamydia trachomatis (CT) replicates in macrophages, but is inhibited by IFN-$\gamma$ or LPS. IFN-$\gamma$ and/or LPS induced nitrite production in mouse peritoneal macrophages, macrophage cell lines (RAW264.7 and J774A.1) and McCoy cells. Kinetic studies indicated that peak production occurred 48 hours post-treatment. CT infection itself was insufficient to induce nitrite production, but resulted in enhancement of nitrite production in IFN-$\gamma$-treated cells. Treatment with IFN-$\gamma$ or LPS resulted in significant inhibition of CT replication in these cells. Strong correlation between nitrite production and inhibition of CT replication was observed in RAW264.7 and J774A.1 cells (correlation coefficients: $-$0.93 and $-$0.94, p $<$ 0.001). N$\sp{\rm g}$- monomethyl-L-arginine (L-NMMA) specifically inhibited nitrite production and partially reversed inhibition of CT replication in macrophage cell lines. NOS mRNA was measured in RAW264.7 cells by Northern blot and Dot blot hybridization. Strong correlation between NOS mRNA expression and inhibition of CT replication (correlation coefficient: $-$0.97, p $<$ 0.05) was observed. Anti-TNF-$\alpha$ antibody completely neutralized the biological activity of TNF-$\alpha$ secreted by LPS-treated RAW264.7 cells, yet the antibody neither reduced nitrite production nor restored CT replication. Combination of the antibody and L-NMMA significantly enhanced restoration of CT replication. In peritoneal macrophages, inhibition of CT replication induced by IFN-$\gamma$ was partially restored by L-NMMA or anti-TNF-$\alpha$ antibody. In McCoy cells, inhibition of CT replication induced by IFN-$\gamma$ and LPS was not significantly restored by L-NMMA. Great restoration of CT replication by 1 mM L-NMMA was observed in LPS-treated J774A.1 cells (31%), but not in IFN-$\gamma$-treated cells (5%). Our data indicate that (1) NO production is one of the mechanisms for inhibition of CT replication in IFN-$\gamma$-activated peritoneal macrophages and RAW264.7 cells; (2) NO plays a significant role in CT inhibition in LPS-treated macrophage cell lines, but not peritoneal macrophages; (3) TNF-$\alpha$ may be associated with inhibition, but the mechanism(s) may not involve NO production; (4) NO production may not be the mechanism for CT inhibition in McCoy cells treated with IFN-$\gamma$ and LPS.