Immunology and Infectious Disease Commons^™

Immune Suppression And Metabolic Reprogramming In Bactrocera Dorsalis Parasitized By Fopius Arisanus, Rehemah Gwokyalya, Jeremy Herren, Thomas Ogao Onchuru, Sahadatou Mama Sambo, Cassandra Purity Ronnie, Ndlela Shepard, Sunday Ekesi, Samira A. Mohamed

All Peer-Reviewed Publications

Abstract – Bactrocera dorsalis is a major horticultural pest. Biocontrol using parasitoids, such as Fopius arisanus, is a sustainable tool for managing this pest. However, the mechanisms enabling the successful parasitism of B. dorsalis are poorly understood. Using transcriptomic profiling, cellular bioassays, and targeted metabolite analyses, we investigated how F. arisanus modulates the immunity and metabolic activity of B. dorsalis to achieve a high parasitism rate. Our results revealed a weak and late encapsulation response of B. dorsalis towards F. arisanus. Additionally, parasitism reduced the number of circulating haemocytes by 35%, lowered constitutive granulocyte counts and inhibited phenoloxidase activity in …

Examining The Ligands, Location, And Function Of Toll-Like Receptor 10, Kiefer Keanu Tam

Master's Theses

Toll-like receptors are a class of innate immune pattern recognition receptors that detect pathogen-associated molecular patterns and regulate downstream inflammatory responses. Toll-like receptor 10 remains the only human TLR whose ligand specificity, cellular localization, and immunological function are not fully defined. Emerging evidence suggests that TLR10 may play an anti-inflammatory role and can heterodimerize with TLR2 to modulate immune signaling. Previous studies from our laboratory demonstrated that stimulation with heat-killed Mycobacterium tuberculosis promotes TLR2-TLR10 heterodimerization and trafficking to the cell surface. In this study, we expanded our ligand panel to include additional gram-positive bacteria, particularly anti-inflammatory probiotic species, to further …

Tlr3 Mediated Type I Interferon Response In Mammalian Cell Defense Against Cryptosporidium Parvum Infection., Anjelica Matias

Biochemistry and Molecular Biology

Cryptosporidium parvum is a major cause of a diarrheal disease which affects many children in the USA as well as the rest of the world, yet the contribution of its double stranded RNA (dsRNA) viral symbiont, Cryspovirus (CSpV1) to host innate immunity remains unclear. This study investigated whether CSpV1 activates Toll Like Receptor 3 (TLR3) signaling pathways and downstream Interferon type I (IFN I) responses in mammalian intestinal epithelial cells. Confluent Human Ileocecal Colorectal Adenocarcinoma cells (HCT8) were exposed to CSpV1, and the expression levels of Tumor Necrosis Factor Receptor-Associated Factor 3 (TRAF3), Nuclear Factor-𝜅-light chain enhancer of activated B-cells …

Investigating The Immunostimulatory Potential Of Dsrna-Silk Nanoparticle Complexes In Melanoma, Samuel J. Peters

Theses and Dissertations (Comprehensive)

The rate of resistance to immune checkpoint inhibitor treatment in metastatic melanoma is quite high, with an overall rate of 70%. Melanoma achieves these high rates of resistance by suppressing the immune response in the tumour microenvironment (TME), making them immunologically “cold”. The type 1 interferon response could be leveraged to initiate immune responses in melanoma, making their “cold” TMEs “warm” again. Double-stranded ribonucleic acids (dsRNAs) are potent activators of an innate immune response; however, they are susceptible to degradation by nucleases present in the body and need a carrier. Silk nanoparticles (SNPs) are an ideal drug-delivery platform as they …

Functional Impact Of Single Nucleotide Polymorphism Rs4129009 (Ile775val) On Human Toll-Like Receptor 10, Audrey N. Koti

Biology Student Research

Toll-like receptors (TLRs) are a subclass of pattern recognition receptors within the

innate immune system that detect pathogen-associated and danger-associated molecular patterns,

thereby initiating host defense responses. The human TLR family comprises ten receptors (TLR1

– TLR10), each recognizing structurally conserved microbial motifs such as bacterial

lipoproteins and viral nucleic acids. The ligand specificities, adaptor protein recruitment, and

downstream signaling cascades have been well-characterized for TLR1 – TLR9, which

predominantly engage MyD88- or TRIF-dependent pathways to activate pro-inflammatory

transcription factors including NF-κB. In contrast, the ligand specificity and intracellular

signaling mechanisms of TLR10 have yet to be fully elucidated. Emerging …

Bmp Signaling Co-Regulation Of Immune Response And Lipid Metabolism, Katerina K. Yamamoto

Dissertations, Theses, and Capstone Projects

The Bone Morphogenetic Proteins (BMPs) are secreted peptide ligands of the Transforming Growth Factor beta (TGF-β) family, initially identified for their roles in development and differentiation across animal species. They are now increasingly recognized for their roles in physiology and infectious disease. In the nematode Caenorhabditis elegans, the BMP ligand DBL-1 controls fat metabolism and immune response, in addition to its roles in body size regulation and development. DBL-1 regulates classical aspects of innate immunity, including the induction of anti-microbial peptides. We theorized that BMP-dependent regulation of fat metabolism could also promote resilience against microbial pathogens. We found that …

Expanding Inducible Epithelial Resistance Against Pneumonia: Novel Virus, Novel Receptor, Michael Longmire

Dissertations and Theses (Open Access)

Pneumonia is the leading infectious cause of death worldwide and presents a continuing risk among immunocompromised patients. Our work has been focused for many years on the phenomenon of inducible epithelial resistance, where activation of the innate immune response in the airway epithelium is necessary and sufficient to produce a pathogen-killing but self-protective environment to prevent severe disease. Inducible resistance is pathogen-agnostic and has been demonstrated against an array of respiratory infections. We achieve this using a combination of pattern recognition receptor agonists – Pam2CSK4 and ODN M362 being the current formulation – which produce synergistic levels of pathogen reduction …

Investigating Genetic Regulators Of Crystal Cell Development In Drosophila Melanogaster, Andrea Feria, Nyla Walbrook, Anisa Turaeva, Rebecca Spokony

Publications and Research

Crystal cells, a subset of Drosophila melanogaster hemocytes, are important for melanization, a crucial immune response. While the genetic regulation of crystal cell develop remains incompletely understood, this study investigates the functions of five candidate genes: ACXB, ACXA, Gp210, CG4390, and Cyp4s3; identidied through previous genome-wide association studies. Using the Gal4/UAS system along with RNA interference (RNAi), we exclusively knocked down each gene in third instar larvae and quantified crystal cell populations following heat shock-induced melanization. Our results imply that the knockdown of ACXB and ACXA significantly increased crystal cell counts in both sexes, suggesting these genes either act as …

Importance Of Specific Nk Cell Subsets For Antitumor Immunity In Hpv+ Cancers, Madison O'Hara

Dissertations and Theses (Open Access)

High-risk type human papillomaviruses (HPV) are associated with genital and oral cancers, and the incidence of HPV+ head and neck squamous cell cancers is fast increasing worldwide. Survival rates for patients with locally advanced disease are poor and variable after standard of care (SOC) treatment. Identifying the antitumor host immune mediators important for treatment response and designing strategies to promote them are essential for improving clinical outcome. The natural killer (NK) cells are a critical component for antitumor innate effector immunity. Among the multitude of activation and inhibitory receptors on immune cells, HLA-DR is recognized as an important activation marker …

The Conceptual Foundations Of Innate Immunity: Taking Stock 30 Years Later, Thomas Pradeu, Bart P.H.J. Thomma, Stephen E. Girardin, Bruno Lemaitre

Presidential Fellows Articles and Research

While largely neglected over decades during which adaptive immunity captured most of the attention, innate immune mechanisms have now become central to our understanding of immunology. Innate immunity provides the first barrier to infection in vertebrates, and it is the sole mechanism of host defense in invertebrates and plants. Innate immunity also plays a critical role in maintaining homeostasis, shaping the microbiota, and in disease contexts such as cancer, neurodegeneration, metabolic syndromes, and aging. The emergence of the field of innate immunity has led to an expanded view of the immune system, which is no longer restricted to vertebrates and …

Large-Scale Phenotyping Of Patients With Long Covid Post-Hospitalization Reveals Mechanistic Subtypes Of Disease, Felicity Liew, Claudia Efstathiou, Sara Fontanella, Matthew Richardson, Ruth Saunders, Dawid Swieboda, Jasmin K Sidhu, Stephanie Ascough, Shona C Moore, Noura Mohamed, Jose Nunag, Clara King, Olivia C Leavy, Omer Elneima, Hamish J C Mcauley, Aarti Shikotra, Amisha Singapuri, Marco Sereno, Victoria C Harris, Linzy Houchen-Wolloff, Neil J Greening, Nazir I Lone, Matthew Thorpe, A A Roger Thompson, Sarah L Rowland-Jones, Annemarie B Docherty, James D Chalmers, Ling-Pei Ho, Alexander Horsley, Betty Raman, Krisnah Poinasamy, Michael Marks, Onn Min Kon, Luke S Howard, Daniel G Wootton, Jennifer K Quint, Thushan I De Silva, Antonia Ho, Christopher Chiu, Ewen M Harrison, William Greenhalf, J Kenneth Baillie, Malcolm G Semple, Lance Turtle, Rachael A Evans, Louise V Wain, Christopher Brightling, Ryan S Thwaites, Peter J M Openshaw, Phosp-Covid Collaborative Group, Isaric Investigators

Faculty, Staff and Student Publications

One in ten severe acute respiratory syndrome coronavirus 2 infections result in prolonged symptoms termed long coronavirus disease (COVID), yet disease phenotypes and mechanisms are poorly understood1. Here we profiled 368 plasma proteins in 657 participants ≥3 months following hospitalization. Of these, 426 had at least one long COVID symptom and 233 had fully recovered. Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment. Additional markers …

The Influence Of Intracellular Photosymbiosis On The Evolution And Function Of Cnidarian Immunity, Madison A. Emery

Biology Dissertations - Archive

Intracellular photosymbiosis with Symbiodiniaceae is facilitated by cnidarian immunity as it is required for symbiont recognition and is subsequently suppressed to maintain stable intracellular symbiosis. To date, it is unclear how the cnidarian-Symbiodiniaceae symbiosis influences immune gene repertoires, immune gene expression, and disease pathology across its independent evolutions. To address these knowledge gaps, my dissertation approaches studying the cnidarian-Symbiodiniaceae symbiosis through a comparative lens to determine how it shapes immune gene evolution and immune responses in divergent symbiotic cnidarian species. In chapter two I survey eight non-symbiotic and seven symbiotic cnidarians proteomes for four families of pattern recognition receptors (PRRs) …

Functional Analysis Of Two Campoletis Sonorensis Ichnovirus Vinnexins In Drosophila Melanogaster, Peng Zhang

All Dissertations

Campoletis sonorensis Ichnovirus (CsIV) is produced by the ichneumonid parasitoid Campoletis sonorensis (the primary host). Female parasitoid wasps restrictedly replicate viruses in their ovaries and inject them into a larval lepidopteran (secondary host) during oviposition. This symbiotic virus of C. sonorensis is essential for successful parasitization. CsIV is characterized by having a large, segmented double-stranded DNA genome with a large number of genes, many of which are associated with one of five multigene families. The CsIV vinnexin gene family is one of them and has four members, including CsIV-vnxD and CsIV-vnxG. Vinnexins are homologues of insect Innexins, which form gap …

Investigating The Roles Of Lung Epithelial Stat3 In Therapeutically Inducible Resistance To Acute Bacterial Pneumonia., Vikram V. Kulkarni, Vikram V. Kulkarni

Dissertations and Theses (Open Access)

Investigating the roles of lung epithelial STAT3 in therapeutically inducible resistance to acute bacterial pneumonia.

Vikram Vitthal Kulkarni, M.S.

Advisory Professor: Scott Evans, MD.

The lung epithelium is a dynamic tissue capable of displaying structural and functional plasticity in response to pathogenic challenges. Our lab has demonstrated that it is possible to therapeutically exploit the lung epithelium’s versatility by inducing resistance to lethal pneumonias caused by viruses, bacteria and fungi. An inhaled combination of a TLR2/6 agonist and a TLR9 agonist (Pam2ODN) results in robust protection against otherwise lethal pneumonia caused by Pseudomonas aeruginosa. Pam2ODN-mediated protection requires key signaling …

Tgf-B Signaling Mechanisms In Caenorhabditis Elegans Response To Bacterial Pathogens, Emma J. Ciccarelli

Dissertations, Theses, and Capstone Projects

When exposed to infection, the nematode C. elegans mounts an innate immune response through secretion of antimicrobial peptides (AMPs). Different signaling pathways in the worm regulate release of these AMPs. One highly conserved pathway is the C. elegans BMP like pathway – regulated by the ligand DBL-1. The DBL-1 pathway is noted for its significant role in development but has also been shown to regulate many post-developmental processes within the worm, including the immune response. We are interested in determining how DBL-1 signaling can mediate a response specific to immunity, separate from its other functions in the worm. Through survival …

Sex-Dependent Effects Of Induced Acute Inflammation On Glucose Homeostasis And Rna Editing Enzymes, Christian A. Rivas

Graduate Theses/Dissertations

The first line of defense against bodily insults, like pathogen invasion, is the innate immune system. Innate immunity sets in motion countless cascades that result in inflammation. Inflammation simultaneously affects multiple biological processes like metabolism and gene expression. Males and females react differently to inflammation. To understand both molecular and physiological sex differences in inflammation, we examined how inflammation affects gene expression and glucose metabolism. Adenosine deaminase acting on RNA (ADAR1) is upregulated by inflammation and catalyzes RNA editing, a process where nucleotides encoded by the genome are modified. ADAR1 also controls the innate immune reaction by decreasing activity of …

Examining The Immune Regulation Of Nlrp12 Through Novel Protein Interactions, Catherine Rippe

Graduate Theses/Dissertations

NOD-like receptors (NLRs) are intracellular proteins that play an important role in the regulation of the innate immune response to pathogens. Since being identified, various functions for NOD-like receptor pyrin domain containing 12 (NLRP12) have been suggested. It has been shown to negatively regulate the inflammatory response through canonical and noncanonical NF-kB signaling pathways, control tumorigenesis and gut homeostasis and exacerbate inflammation through the formation of a multi-protein complex called an inflammasome. Due to the varying roles established for NLRP12, the mechanisms by which it functions remain poorly understood. In this study, I sought to confirm a novel protein-protein interaction …

Innate Immunity In The Pathobiology And Treatment Of Infectious And Neurodegenerative Diseases, Mai Mostafa

Theses & Dissertations

Mononuclear phagocytes (MPs; monocytes, macrophages, and dendritic cells) are the governors of innate immunity which is the body’s first line of defense against microbial pathogens. They act beneficial or detrimental. They are crucial for an effective non-specific immune response to invading pathogens by engulfing, destroying, then eliciting an adaptive specific immune response. Given their pivotal functions in the host immune defense, studying MP immune responses in disease is paramount important for understanding disease pathobiology and uncovering therapeutic strategies.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the driver of acute respiratory distress syndrome (ARDS) in coronavirus disease 2019 (COVID-19) amongst …

Time Course Investigation Of The Dermal Leukocyte Response To Lipoteichoic Acid In Chickens, Ian Gilbert

Animal Science Undergraduate Honors Theses

Lipoteichoic acid (LTA) is component of the cell wall of Gram-positive bacteria that stimulates inflammation during bacterial infection. However, few studies have investigated the in vivo immune response to LTA, and none of the in vivo studies done have been performed in birds. For this project, the pulp (a skin-derivative) of growing feathers (GFs) of chickens were used as a test site to investigate the in vivo effects of intradermally injected LTA. In Study 1, the pulp of 12 GFs of 11-week-old Light-brown Leghorn (LBL) males were injected with 10 μL of differing concentrations of LTA (0.1, 1.0, 10, 100 …

Epithelial Immunomodulation By Aerosolized Toll-Like Receptor Agonists Prevents Allergic Inflammation In Airway Mucosa In Mice, David L Goldblatt, Gabriella Valverde Ha, Shradha Wali, Vikram V Kulkarni, Michael K Longmire, Ana M Jaramillo, Rosha P Chittuluru, Adrienne Fouts, Margarita Martinez-Moczygemba, Jonathan T Lei, David P Huston, Michael J Tuvim, Burton F Dickey, Scott E Evans

Faculty, Staff and Student Publications

Allergic asthma is a chronic inflammatory respiratory disease associated with eosinophilic infiltration, increased mucus production, airway hyperresponsiveness, and airway remodeling. Epidemiologic data reveal that the prevalence of allergic sensitization and associated diseases has increased in the twentieth century. This has been hypothesized to be partly due to reduced contact with microbial organisms (the hygiene hypothesis) in industrialized society. Airway epithelial cells, once considered a static physical barrier between the body and the external world, are now widely recognized as immunologically active cells that can initiate, maintain, and restrain inflammatory responses, such as those that mediate allergic disease. Airway epithelial cells …

Time Course Investigation Of The Dermal Leukocyte Response To Lipoteichoic Acid In Chickens, Ian M. Gilbert, Jossie M. Santamaria, Gisela F. Erf

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Lipoteichoic acid (LTA) is a cell-wall polymer in Gram-positive bacteria that stimulates inflammation. Few studies have investigated in vivo immune response to LTA, and none of the in vivo studies have been performed in birds. For this project, the pulp (a skin derivative) of growing feathers (GF) of chickens was used to investigate the in vivo effects of intradermally injected LTA. In Study 1, GF of chickens were injected with 10 μL of differing concentrations of LTA (0.1, 1.0, 10, 100 or 250 μg LTA/mL; 3 chickens/dose). Growing feathers were plucked before injection (0 h) and at 6, 24, 48, …

Dicer Represses Antiviral Innate Immunity Pathways In Mouse Embryonic Stem Cells, Chandan Gurung

Dissertations

Recent studies have demonstrated that embryonic stem cells (ESCs) are deficient in expressing type I interferons (IFN), the cytokines that play key roles in antiviral responses. However, the underlying molecular mechanisms and biological implications of this finding are poorly understood. In this study, I used a synthetic RNA-based assay that can simultaneously assess multiple forms of antiviral responses in ESCs. Dicer is an enzyme essential for RNA interference (RNAi), which is used as a major antiviral mechanism in invertebrates but not clear in vertebrates. RNAi activity is detected in wild-type ESCs but is abolished in Dicer knockout ESCs (D−/−ESCs) as …

Harnessing The Power Of Trained Immunity In The Setting Of Pancreatic Cancer: A Novel Mechanism Of Immune Trafficking And Tumor Control., Anne Elena Geller

Electronic Theses and Dissertations

Despite the success of immunotherapy in many types of cancer, pancreatic adenocarcinoma (PDAC) has yet to benefit. Innate immune cells are critical to antitumor immunosurveillance and recent studies have revealed that these populations possess a form of memory, termed trained innate immunity, which occurs through transcriptomic, epigenetic, and metabolic reprograming. Though trained innate immunity has mostly been investigated in the context of infection, the induction of trained innate immunity could also protect against tumors, and specifically pancreatic tumors. Here, we demonstrate that yeast-derived particulate β-glucan, a known inducer of trained immunity, traffics to the pancreas following IP administration. This causes …

Molecular And Genetic Studies On A Sipd/Ipad-Related Virulence Spike Protein From Immune-Suppressive Particles Of A Drosophila Parasitoid, Carlo Miguel A. Sevilla

Dissertations and Theses

Parasitoid wasps are effective biological control agents that have evolved intricate host immune suppression strategies to overcome host immune defenses. The most important anti-parasite defense mechanism is encapsulation, where the host’s blood cells surround the wasp egg. In the Drosophila/Leptopilina host-parasitoid system, extracellular vesicles (EVs) are oviposited along with the wasp egg. The EVs possess spikes and contain hundreds of proteins, some of which enable wasp eggs to escape encapsulation by changing the morphology and function of hemocytes, or killing them. Previous studies have identified an abundant surface/spike protein (SSp40) from Leptopilina heterotoma EVs. While p40, a predicted …

Plasmodium Impairs Antibacterial Innate Immunity To Systemic Infections In Part Through Hemozoin-Bound Bioactive Molecules., Christopher Lynn Harding

Electronic Theses and Dissertations

Despite efforts to decrease the global health burden of malaria, infections with Plasmodium species continue to cause over 200 million episodes of malaria each year which resulted in 405,000 deaths in 2018 [1]. One complication of malaria is increased susceptibility to invasive bacterial infections. Plasmodium infections impair host immunity to non-Typhoid Salmonella (NTS) through activities of heme oxygenase I (HO-I) )-induced release of immature granulocytes and myeloid cell-derived IL-10. Yet, it is not known if these mechanisms are specific to NTS. We show here, that Plasmodium yoelii 17XNL (Py) infected mice had impaired clearance of systemic Listeria monocytogenes (Lm) during …

Defective Early Innate Immune Response To Ectromelia Virus In The Draining Lymph Nodes Of Aged Mice Due To Impaired Dendritic Cell Accumulation., Colby Stotesbury, Eric B Wong, Lingjuan Tang, Brian Montoya, Cory J Knudson, Carolina R Melo-Silva, Luis J Sigal

Department of Microbiology and Immunology Faculty Papers

It is known that aging decreases natural resistance to viral diseases due to dysfunctional innate and adaptive immune responses, but the nature of these dysfunctions, particularly in regard to innate immunity, is not well understood. We have previously shown that C57BL/6J (B6) mice lose their natural resistance to footpad infection with ectromelia virus (ECTV) due to impaired maturation and recruitment of natural killer (NK) cells to the draining popliteal lymph node (dLN). More recently, we have also shown that in young B6 mice infected with ECTV, the recruitment of NK cells is dependent on a complex cascade whereby migratory dendritic …

Effects Of Individual Orsay Virus Proteins On The Intracellular Pathogen Response Of C. Elegans, Barbara Chen, Jessica N. Sowa

Biology Student Work

In order to cause infection, pathogens must avoid destruction by the host immune system. However, how pathogens evolved to evade host immunity is not fully understood. Mammals have two systems of immunity, innate and adaptive, which are regulated by complex interactions between the two systems. In order to study innate immunity exclusively, the roundworm C. elegans is a useful invertebrate model because it lacks adaptive immunity and the complexities that arise from interactions between the two types of immunity. The goal of this project is to investigate whether the individual expression of the Orsay virus capsid and delta-fusion proteins can …

Identifying Novel Triggers Of The Intracellular Pathogen Response (Ipr) In C. Elegans, Catherine T. Byrnes, Jessica N. Sowa

Biology Student Work

The intracellular pathogen response (IPR) is a cell signaling pathway found in C. elegans that is triggered when pathogenic microorganisms invade, and immune responses attempt to eliminate the threat. Due to the relative simplicity of C. elegans, they are an excellent model organism to analyze the cell signaling pathways triggered by various pathogens. They lack the complex immune systems of larger organisms, making it easier to study the involved cell signaling pathways. Past studies have shown that the IPR can also be triggered via intestinal wounding. Heat stress, viral infection, and proteasome stress are all known triggers of the IPR. …

Innate Antibodies, Murine Models, And Evolution: A Study Of Trypanosome Lytic Factor Functions And Their Translational Applications, Joseph P. Verdi

Dissertations, Theses, and Capstone Projects

Trypanosome lytic factors (TLFs) are primate-specific antimicrobial protein complexes that lyse African trypanosome parasites by delivering the channel-forming toxin APOL1 to the invading microorganisms. Human serum contains two TLFs that are delivered to the parasite by separate mechanisms, only one of which has been characterized. TLF1 is endocytosed by a receptor that is typically blocked by other serum factors in vivo, suggesting that TLF2 is the more relevant lytic factor in the context of trypanosome immunity. TLF2 is non-covalently associated with polyclonal immunoglobulin M (IgM) antibodies, which we report here to be involved in the uptake mechanism. The TLF2-IgMs …

Neutrophils From Both Susceptible And Resistant Mice Efficiently Kill Opsonized Listeria Monocytogenes, Michelle G. Pitts, Travis A. Combs, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Inbred mouse strains differ in their susceptibility to infection with the facultative intracellular bacterium Listeria monocytogenes, largely due to delayed or deficient innate immune responses. Previous antibody depletion studies suggested that neutrophils (polymorphonuclear leukocytes [PMN]) were particularly important for clearance in the liver, but the ability of PMN from susceptible and resistant mice to directly kill L. monocytogenes has not been examined. In this study, we showed that PMN infiltrated the livers of BALB/c/By/J (BALB/c) and C57BL/6 (B6) mice in similar numbers and that both cell types readily migrated toward leukotriene B4 in an in vitro chemotaxis assay. However, …