ImmunoHorizons

RationaleThe lung is a unique immunological niche with diverse immune cell types. The effects of stimulation through innate and adaptive immune receptors on human lung immune cells has largely been extrapolated from studies of blood immune cells. While multiple immune cell types and many genes have been implicated as contributing to asthma, the dynamics of these in human lung immune cells following activation will yield insights into asthma pathogenesis and lung immunity more broadly. Methods and MeasurementsHuman lung immune cells from 6 donors were isolated. Mixed leukocytes were treated separately with lipopolysaccharide (LPS), F(ab)2-anti-human-IgM/IgG + IL4 and anti-CD3/CD28 for 4 and 18 hours and underwent single cell RNA sequencing (scRNAseq). Lung immune cell types were annotated, and gene expression compared across conditions. Genes at prior asthma-associated genetic loci were characterized across cell types, treatments and timepoints. Expression of non-classical class II genes associated with asthma, HLA-DQA2 and HLA-DQB2, and their protein products was characterized with immunohistochemistry. Main ResultsWe characterized gene expression in 116,697 lung immune cells. Cell-, treatment-, and timepoint-specific effects on gene expression were detected in all lung immune cell populations. Correlation of gene expression between lung and blood lymphocyte populations decreased following stimulation. Among the genes that were differentially expressed, 97 receptor:ligand pairs had changes with treatments. 96.0% of genes at asthma risk loci demonstrated differential expression in at least one cell type and at least one treatment. B cells were the cell type with the highest expression of HLA-DQA2 and HLA-DQB2 which increased with anti-IgM/IgG treatment and the HLA-DQ{beta}2 protein was identified in lung B cells from a donor with asthma. ConclusionsHuman lung immune activation elicits a broad range of cellular responses that deviate from those of blood immune cells and are relevant to asthma. Lung B cells expressing HLA-DQA2 and HLA-DQB2 appear to be involved in a novel antigen presentation pathway that contributes to asthma risk.

IntroductionBacterial pulmonary infections are a major cause of morbidity and mortality in neonates, with less severity in older children. Previous studies demonstrated that the DNA of CD4+ T cells in the mouse lung, whose primary responsibility is to coordinate the immune response foreign pathogens, is differentially methylated in neonates compared with juveniles. Nevertheless, the effect of this differential DNA methylation on CD4+ T cell gene expression and response to infection remains unclear. MethodsWe treated E. coli-infected neonatal (4-day-old) and juvenile (13-day-old) mice with decitabine (DAC), a DNA methyltransferase inhibitor with broad-spectrum DNA demethylating activity, and performed simultaneous genome-wide DNA methylation and transcriptional profiling on lung CD4+ T cells. ResultsJuvenile and neonatal mice experienced differential demethylation in response to DAC treatment, with larger methylation differences observed in neonates. By cross-filtering differentially expressed genes between juveniles and neonates with those sites that were demethylated in neonates, we found that interferon-responsive genes such as Ifit1 are the most down-regulated methylation-sensitive genes in neonatal mice. DAC treatment shifted neonatal lung CD4+ T cells toward a gene expression program similar to that of juveniles. ConclusionFollowing lung infection with E. coli, lung CD4+ T cells in neonatal mice exhibit epigenetic repression of important host defense pathways, which are activated by inhibition of DNA methyltransferase activity to resemble a more mature profile.

FOXP3+ regulatory T (Treg) cells are necessary to coordinate resolution of lung inflammation and a return to homeostasis after respiratory viral infections, but the specific molecular requirements for these functions and the cell types governed by Treg cells remain unclear. This question holds significance as clinical trials of Treg cell transfer therapy for respiratory viral infection are being planned and executed. Here, we report causal experiments in mice determining that Treg cells are necessary to control the numbers of activated CD8+ T cells during recovery from influenza infection. Using a genetic strategy paired with adoptive transfer techniques, we determined that Treg cells require the transcription factor TBET to regulate these potentially pro-inflammatory CD8+ T cells. Surprisingly, we found that Treg cells are dispensable for the generation of CD8+ lung tissue resident-memory T (Trm) cells yet similarly influence the transcriptional programming of CD8+ Trm and activated T cells. Our study highlights the role of Treg cells in regulating the CD8+ T cell response during recovery from influenza infection.

Bcl-3 is an atypical member of the I{kappa}B protein family that plays important and diverse roles in both innate and adaptive immunity, including Th17-dependent autoimmunity models in mice. When naive mouse splenic CD4+ T cells were cultured under Th17 conditions in vitro, we unexpectedly found that the most highly differentially expressed gene between wild type and Bcl-3-deficient (KO) Th17 cells encoded the cytokine IL-9. We therefore investigated the role of Bcl-3 in Th9 cell differentiation. When naive CD4+ T cells were cultured under Th9-polarizing conditions in vitro, the extent of Th9 differentiation observed in wild type cells was increased in Bcl-3 KO cells and conversely was decreased in cells overexpressing Bcl-3. The suppressive effect of Bcl-3 on Th9 differentiation was cell-autonomous, and NF-{kappa}B inhibitors abolished increased Th9 differentiation in Bcl-3 KO cells. Consistent with this, in the Th9 transfer model of OVA-induced allergic airway inflammation, mice receiving Bcl-3 KO cells had greater immune cell infiltration in the lung than mice receiving wild type cells. Mechanistically, unsupervised transcriptomic analysis revealed differentially expressed genes in KO cells, including the glutamine transporter Slc1a5, which was downregulated. The functional significance of this was suggested by the ability of increasing concentrations of glutamine in the media to reduce the difference in Th9 differentiation between WT and KO cells. Our results suggest a novel role for Bcl-3 as a negative regulator of Th9 differentiation, in part by limiting glutamine accessibility through downregulation of Slc1a5.

This Optimized Multiparameter Immunofluorescence Panel (OMIP) reports on the development of a mass cytometry panel for broad immunophenotyping of leukocytes from bronchoalveolar lavage from rhesus macaques. Using this panel, we were able to identify myeloid populations such as macrophages, neutrophils, monocytes, myeloid and plasmacytoid DCs, basophils and lymphoid cell lineages including B cells, natural killer (NK) cells, mucosal associated invariant T (MAIT) cells, {gamma}{delta} T cells, CD4 T cells, CD8{square}{beta} T cells, CD8 {square}{square} T cells, and innate lymphoid cells (ILCs). We also included markers for defining memory, differentiation (CCR7, CD28, CD45RA), homing potential (CXCR3), cytotoxic potential (perforin, granzyme B, granzyme K), cell activation/differentiation (HLA-DR, CD69, IgD) and effector function (CD154, IFN-{gamma}, TNF, IL-2, IL-17A, IL-6, IL-1{beta}, CCL4 and CD107a). This panel was optimized on cryopreserved, bronchoalveolar lavage and splenocytes collected from rhesus macaques. The antibodies selected in this panel are human-specific antibodies that have been shown to cross-react with non-human primates except for CD45 clone D058-1283 which is specific for non-human primates.

Notch ligands are present during the interactions between T cells and dendritic cells (DC) and induce a myriad of effects that facilitate the activation of T cells, including the induction of T cell regulation, survival, and cytokine production. Although the ligands Delta-like 4 and Delta-like 1 are expressed as a function of DC activation, the notch ligand Jagged-1 is constitutively expressed on DC. We sought to determine the role of Jagged-1 in the interactions between CD4+ T cells and DC. We observed that Jagged-1 regulates Foxp3 expression, and Cd11cCre+Jaggedff mice have an altered expression of Foxp3 in effector cells that arise as a result of infection with the mycobacterium Bacille Calmette-Guerin. The observed changes in Foxp3 expression were correlated with an increase in cytokine production from cultures of antigen-stimulated draining lymph nodes.

Macrophages serve as important sites of bacterial replication and host immune response during Mycobacterium tuberculosis (Mtb) infection with distinct roles for alveolar macrophages (AMs) early in infection and monocyte-derived (MDMs) during later stages of disease. Here, we leverage data from human and mouse models to perform a cross-species analysis of macrophage responses to Mtb infection. Overall, we find that both subsets of human and murine macrophages mount a strong interferon response to Mtb infection. However, AM across both species do not generate as strong a pro-inflammatory response as human MDMs or murine bone marrow-derived macrophages (BMDMs), as characterized by TNFA signaling and inflammatory response pathways. Interestingly, AMs from mice that were previously vaccinated with BCG (scBCG) or from a model of contained TB (coMtb) had Mtb responses that were more similar to human AMs than control mice. We also identify species-specific pathways altered by infection differently in mouse and human macrophages, specifically in pathways related to cholesterol in AMs as well as MYC targets and Hedgehog signaling in MDMs/BMDMs. Lastly, to investigate downstream effects of the macrophage interferon responses, we examine macrophage expression of IL-10, an immunosuppressive cytokine induced by Type I Interferons, and c-Maf, a transcription factor required for IL-10 expression in myeloid cells. We find that c-Maf and IL-10 have significantly lower expression in AMs compared to MDMs in both humans and mice, suggesting one possible mechanism by which AMs mount a stronger interferon response following Mtb infection. Overall, these results highlight the dynamics of innate myeloid responses over the course of Mtb infection and the benefit of a combined analysis across species to reveal conserved and unique responses.

Treatment of antibiotic-resistant Acinetobacter baumannii infections has become exceedingly challenging, leading to higher morbidity and mortality. Therefore, the development of new therapeutics to treat these infections is critically needed, and immunotherapy is one potential treatment option. Immune responses against this pathogen, particularly lymphocyte- mediated responses, are not well understood. In this study, we investigated the role of B cells in innate resistance to A. baumannii pulmonary infection using a B cell-deficient ({micro}MT) mouse model. B cell-deficient mice were impaired in clearing A. baumannii from the lung, liver, and spleen and failed to prevent extrapulmonary dissemination of A. baumannii after infection. Transcriptomic analyses indicated that the lack of B cells was associated with reduced expression of several genes encoding antimicrobial proteins. In addition, B cell deficiency was associated with pulmonary eosinophilia and increased pulmonary recruitment of Ly6C+ NK cells following A. baumannii infection. This study demonstrates the significant role of B cells in providing early protection against A. baumannii infection and implicates B cell-dependent mechanisms beyond antibody-mediated bacterial resistance.

The skin lesion erythema migrans (EM) is the first clinical sign of Lyme disease, an infection due to the tick-transmitted bacterium Borrelia burgdorferi (Bb). Previously, we used scRNA-Seq to characterize the cutaneous immune response in the EM lesion, focusing on B cells. Here, with an expanded sample size, we profiled T cell responses in EM lesions compared to autologous uninvolved skin. In addition to CD4+ T cell subsets known to be abundant in the EM, we identified clonal expansion of CD8+ GZMK+ IFNG+ T cells that exhibited significant differential expression of interferon-regulated genes. This subset included IFNG+ cells with low cytotoxic gene expression, which may promote inflammation. While FOXP3+ regulatory T cells were also increased in EM, they exhibited little IL10 expression. In contrast, a CD4+ FOXP3- tissue-resident T cell subset contained the largest population of cells with IL10 expression. Fibroblasts, endothelial cells, and pericytes were the principal cells that significantly differentially expressed key T cell-recruiting chemokines. These studies represent the first comprehensive interrogation of the cutaneous T cell response to Bb infection using single cell transcriptomics with adaptive immune receptor sequencing, providing insight into the skin barrier defense and orchestration of the immune response to this vector-borne pathogen.

CD8 T cell differentiation is controlled by the crosstalk of various transcription factors and epigenetic modulators. Uncovering the different players in regulating this process is fundamental to improving immunotherapy and designing novel therapeutic approaches. Here, we show that Polycomb Repressive Complex (PRC)1 subunit Chromobox (Cbx)4 favors differentiation to effector CD8 T cells. Cbx4 deficiency in CD8 T cells induced transcriptional signature and phenotype of memory cells, increasing the formation of memory population during acute viral infection. It has been previously shown that besides chromodomain-mediated binding to H3K27me3, Cbx4 function as a SUMO E3 ligase in a SUMO interacting motifs (SIM)-dependent way. The overexpression of Cbx4 mutants in distinct domains showed that this protein regulates CTL differentiation primarily in a SIM-dependent way and partially through its chromodomain. Our data revealed a novel role of a Polycomb group protein Cbx4 controlling CD8 T lymphocyte differentiation and indicates the SUMOylation process as a key molecular mechanism connected to chromatin modification in this process. SummaryUnderstanding the epigenetic control of CTL differentiation is critical for the manipulation of these cells in immunotherapy protocols. This article demonstrates a novel role for Cbx4, a Polycomb-group protein, in supporting CD8 T cell commitment to an effector cell phenotype.

The immune regulatory gene PTPN22 is expressed in all immune cells and encodes Lyp in humans and the ortholog PEP in mice. The PTPN22 alternative allele, 1858C>T, is expressed in 5-15% of the North American population and is strongly associated with the development of autoimmune disease while simultaneously capable of providing protection during virus infection and cancer. In murine models, significant progress has been made in elucidating the molecular mechanisms that PEP and its pro-autoimmune variant (PEP-R619W) modulate T cell function, yet their influence on non-T cell pathways, such as antigen presenting cell cytokine production, remains less defined. Previously, it was reported that PEP promotes type I interferon (IFN-I) production in dendritic cells (DCs) and macrophages following TLR4 stimulus. Here, we show that contrary to previous results, both PEP-WT and the PEP-R619W variant do not promote IFN-I production in DCs and macrophages following exposure to LPS, 3p-hpRNA, or coronavirus MHV A59. We attribute the prior findings to mouse strain-specific differences and conclude that factors independent of PEP may be regulating IFN-I production in these studies. We further show that PEP and its R619W variant distinctly modulate the production of TNF, IL-12 and IL-2 in DCs following LPS stimulus. Taken together, our results challenge the current understanding of the role of PEP during inflammation while providing new insight into how the PEP-R619W variant may alter myeloid cell function during disease.

While age-associated B cells (ABCs) are known to expand and persist following viral infection and during autoimmunity, their interactions are yet to be studied together in these contexts. Epstein-Barr virus (EBV) infection has long been implicated in multiple sclerosis (MS), and it is not known whether ABCs could play a role in mediating viral contribution to autoimmunity. Here, we show that the circulating ABC population is expanded in people with MS and that EBV infection and MS status differentially impact the circulating ABC phenotype. We then directly compared ABCs during viral infection and autoimmunity using mouse models of EBV, gammaherpesvirus 68 ({gamma}HV68), and MS, experimental autoimmune encephalomyelitis (EAE). We observed that splenic ABCs are expanded in a sex-biased manner during both latent virus infection and EAE, and each event drives the ABC population to opposing phenotypes. We have previously shown that latent{gamma} HV68 infection exacerbates EAE and here we show that mice lacking ABCs fail to display{gamma} HV68-enhanced disease. Collectively, these findings indicate that latent viral infection and central nervous system autoimmunity differentially impact the ABC population and suggests that viral infections such as EBV prime ABCs to contribute pathogenically in MS.

There is mounting evidence that macrophage-fibroblast communication is key to the understanding of disease processes. To gain insights into these relationships in the context of progressive lung damage, we measured changes in protein and RNA expression of pulmonary macrophages and fibroblasts upon exposure to IL-33, IL-13, and IL-17A, which are three cytokines often implicated in pathways driving chronic lung remodeling and severe disease like emphysema. Applying an in vitro culture system, bulk-RNA sequencing, and protein assays, it was determined that IL-33, IL-13, and IL-17A used alone or in combination activated mouse alveolar macrophages to a modest extent with IL-13 inducing the most vigorous response. While lung fibroblasts also responded modestly to single and paired treatments with IL-33, IL-13, and IL-17A, simultaneous exposure to all three cytokines induced significant activation that was characterized by expression of genes associated with immune cell trafficking and activation, tissue remodeling, and maintenance of the extracellular matrix. Importantly, factors secreted by triple-treated lung fibroblasts resulted in the activation of macrophages in vitro. In addition to being the first report describing the cooperative interactions of IL-33, IL-13, and IL-17A on lung fibroblasts, these findings provide additional evidence that fibroblast-macrophage communication is a key component to repair and remodeling in the lung, as well as mechanisms that drive progression of emphysema.

If we are to break new grounds in TB research, we need to have a complete understanding of what is occurring at the site of infection in humans. Postmortem studies give us an opportunity to compare TB-involved and -uninvolved tissues, in both diseased and non-diseased individuals. We examined the feasibility of carrying out a postmortem study in Mulago and Kiruddu National Referral Hospitals in Uganda, to determine whether we could use immune cells collected postmortem for immunological studies. We report that we can consent the Next-of-Kin, perform postmortem procedures and process tissues within 8 hours of death, and that immune cells remain viable and functional up to 14 hours after death. We found subtle differences in T cell subsets within TB groups. We found a depletion of the CD4 CD69+CD103+ T cell subset in the lungs and BAL, which was associated with HIV, and that the CD8 CD69+CD103- T cell subset was depleted in BAL only, and was associated with TB. Our data show overall changes Tissue Resident Memory T cells within, and between, TB-infected and TB-uninfected human lungs. SummaryO_LICoroner led postmortem studies are possible in Uganda, samples processed within 8 hours from death C_LIO_LICells from samples collected postmortem are viable and functional C_LIO_LIHIV associated depletion of CD4 CD69+/CD103+ T cell subset in lungs and BAL C_LIO_LICD8 CD69+/CD103- depletion in BAL associated with TB C_LI

Macrophages play a crucial role in eliminating respiratory pathogens. Both pulmonary resident alveolar macrophages (AMs) and recruited macrophages contribute to detecting, responding to, and resolving infections in the lungs. Despite their distinct functions, it remains unclear how these macrophage subsets regulate their responses to infection, including how activation by the cytokine IFN{gamma} is regulated. This shortcoming prevents the development of therapeutics that effectively target distinct lung macrophage populations without exacerbating inflammation. We aimed to better understand the transcriptional regulation of resting and IFN{gamma}-activated cells using a new ex vivo model of AMs from mice, fetal liver-derived alveolar-like macrophages (FLAMs), and immortalized bone marrow-derived macrophages (iBMDMs). Our findings reveal that IFN{gamma} robustly activates both macrophage types; however, the profile of activated IFN{gamma}-stimulated genes varies greatly between these cell types. Notably, FLAMs show limited expression of costimulatory markers essential for T cell activation upon stimulation with only IFN{gamma}. To understand cell type-specific differences, we examined how the inhibition of the regulatory kinases GSK3/{beta} alters the IFN{gamma} response. GSK3/{beta} controlled distinct IFN{gamma} responses, and in AM-like cells, we found GSK3/{beta} restrained the induction of type I IFN and TNF, thus preventing the robust expression of costimulatory molecules and limiting CD4+ T cell activation. Together, these data suggest that the capacity of AMs to respond to IFN{gamma} is restricted in a GSK3/{beta}-dependent manner and that IFN{gamma} responses differ across distinct macrophage populations. These findings lay the groundwork to identify new therapeutic targets that activate protective pulmonary responses without driving deleterious inflammation.

Autophagy proteins have been linked with development of immune-mediated diseases including lupus, but the mechanisms for this are unclear. We have previously shown that non-canonical autophagy induced by v-integrins regulates B cell activation by viral and self-antigens in mice. Here we investigated the involvement of this pathway in B cells from human tissue. Our data revealed that autophagy is specifically induced in germinal-center and memory B cell sub-populations from human tonsil and spleen. Transcriptomic analysis showed that induction of autophagy is related to unique aspects of activated B cells such as mitochondrial metabolism. To understand the function of non-canonical autophagy in B cells, we used CRISPR-mediated knockdown of autophagy genes. Integrating data from primary B cells and knockout cells we found that v-integrin-related non-canonical autophagy limits activation of specific pathways while promoting others. These data provide new mechanistic links for autophagy and immune dysregulation in diseases such as lupus.

Heterogeneous nuclear ribonucleoprotein A2B1 (HNRNPA2B1) is a well known RNA binding protein but the mechanisms by which it contributes to innate immune gene regulation are poorly understood. Here we report that HNRNPA2B1 functions in macrophages to regulate IFNG (IFN-{gamma}) signaling through alternative splicing of the IFNG receptor. Specific deletion of HNRNPA2B1 in macrophages resulted in altered cytokine responses in both an endotoxic shock model and following Salmonella infection. Interestingly, while HNRNPA2B1 can function as a viability gene, we observed increased macrophage and neutrophil numbers in the KO mice following LPS induced endotoxic shock. We also discovered that HNRNPA2B1 restricts replication of Salmonella enterica in vivo. Mechanistically, loss of HNRNPA2B1 resulted in an increase in NGO transcripts, which lack a start codon, of the IFNG receptor (Ifngr) leading to lower expression of the receptor at the cell surface impacting the downstream IFNG signaling cascade. Collectively, our data highlight an important role for HNRNPA2B1 in regulating IFNG signaling and restricting intracellular bacterial pathogens in macrophages.

BackgroundAberrant CD8 T-cell differentiation contributes to the pathogenesis of autoimmune diseases, and immune-mediated tissue damage. However, the molecular mechanisms that prevent premature effector T cell programming in humans remain incompletely defined. Signal regulatory protein gamma (SIRP{gamma}) is selectively expressed on T-cells in the human immune system. Notably, genetic variants associated with reduced SIRP{gamma} expression have been linked to increased risk of immune-mediated diseases, including type 1 diabetes and multiple sclerosis, but the contribution of SIRP{gamma} to CD8 T-cell dysregulation in these contexts remains unclear. ObjectiveTo determine how inter-individual variation in SIRP{gamma} expression influences immune homeostasis and CD8 T-cell effector programming. MethodsPeripheral blood CD8 T-cells from healthy donors were analyzed for SIRP{gamma} expression and associated differentiation phenotypes. Naive CD8 T-cells were purified and subjected to siRNA-mediated knockdown of SIRPG, followed by suboptimal TCR stimulation. Differentiation status, transcription factor expression, and effector cytokine production were measured using flow cytometry. CD47 blockade was used to assess ligand dependency. ResultsLow SIRP{gamma} expression on CD8 T-cells was associated with increased frequencies of CD27-CD45RO effector-like and CD27-CD45RO- terminally differentiated CD8 T-cells. SIRPG knockdown induced effector-like differentiation, with increased CD45RO and T-bet expression and elevated TNF-, IFN-{gamma}, and Granzyme B production. This effect was not recapitulated by CD47 blockade, suggesting a CD47-independent regulatory mechanism. ConclusionSIRP{gamma} serves as a negative regulator of CD8 T-cell effector differentiation under suboptimal stimulation. Inter-individual variation in its expression may influence susceptibility to immune dysregulation, positioning it as a potential biomarker and therapeutic target.

ABSTRACTInflammatory control is critical to recovery from respiratory viral infection. Acetylcholine (ACh) secreted from non-neuronal sources, including lymphocytes, plays an important, albeit underappreciated, role in regulating immune-mediated inflammation. This study was designed to explore the role of ACh in acute viral infection and recovery. Using the murine model of influenza A, cholinergic status in the lungs and airway was examined over the course of infection and recovery. The results showed that airway ACh remained constant through the early stage of infection and increased during the peak of the acquired immune response. As the concentration of ACh increased, cholinergic lymphocytes appeared in the airway and lungs. Cholinergic capacity was found primarily in CD4 T cells, but also in B cells and CD8 T cells. The cholinergic CD4+ T cells bound to influenza-specific tetramers at the same frequency as their conventional (i.e., non-cholinergic) counterparts. In addition, they were retained in the lungs throughout the recovery phase and could still be detected in the resident memory regions of the lung up to two months after infection. Histologically, cholinergic lymphocytes were found in direct physical contact with activated macrophages throughout the lung. When ACh production was inhibited, mice exhibited increased tissue inflammation, altered lung architecture, and delayed recovery. Together, these findings point to a previously unrecognized role for ACh in the transition from active immunity to recovery and pulmonary repair following respiratory viral infection.View Full Text

Autoimmune diseases, such as systemic lupus erythematosus (SLE), are underscored by dysregulated B cell function including the production of autoantibodies, skewed population ratios, and aberrant signaling. Given that the family of nuclear factor kappa B (NF-{kappa}B) transcription factors govern responses to stimuli, survival, differentiation, and so forth understanding the intricate regulatory network of NF-{kappa}B in B cell biology is paramount for unraveling treatments for B cell-linked autoimmune diseases. Here, we focus on a negative regulator of NF-{kappa}B signaling, A20 (TNFAIP3), that deactivates NF-{kappa}B transcription factor translocation through the ubiquitination and deubiquitination of target proteins. Haploinsufficiency in A20 results in an autoimmune phenotype and mutations to A20 have been associated with SLE, suggesting implications to B cell function. To investigate the role of A20 in NF-{kappa}B in human B cells, we generated a TNFAIP3 knockout (KO) Raji cell line. Cells were stimulated with either anti-IgM or Resiquimod (R848) to activate distinct NF-{kappa}B signaling pathways. Using qRT-PCR, western blotting, and flow cytometry, we assessed differences in gene expression, protein production, and NF-{kappa}B activation. We observed key limitations in using Epstein-Barr virus transformed B cell lines to model inducible NF-{kappa}B signaling.