Absence Of Lymphocytes Research Articles

Skull bone marrow serves as a niche of adaptive immunity for CNS immunosurveillance

Abstract The central nervous system (CNS) has been considered as an ‘immune-privileged’ organ owing to limited graft- and cancer-rejection, as well as the absence of lymphocytes and lymphatics. However, recent findings unveiled that the immune system actively discerns the status of the CNS through the glymphatic system and meningeal lymphatics. There is a diverse immune repertoire in the CNS borders presenting antigen, affecting behaviors, and defending CNS tissues. Recent studies discovered the channels in the skull bone marrow (SBM), exchanging immune cells and cerebrospinal fluid (CSF). Consequently, molecular exchange and immune cell activation occur in the CNS border, including SBM, like mucosal tissues. Nevertheless, the mechanism responding to CNS antigens and the maintenance of tolerance is unclear. In this study, we noted greater activation and differentiation of T/ B cells in the SBM than dura mater and other BMs. SBM displayed premature features of lymphoid structures, encompassing Tfh, activated B cells, and antibody-secreting cells. We also observed that Tfh cells directly interacted with B cells and induced differentiation. Moreover, our observations indicated that skull T/B cells respond to CNS antigens, but not microbial/food antigen. Thus, our study suggests that the SBM is a niche for adaptive immune cells in response to CNS antigens. The SBM may sustain heightened inflammatory states to promptly counteract tumorigenesis and pathogen invasion, protecting CNS.

HLA-B*57:01-dependent intracellular stress in keratinocytes triggers dermal hypersensitivity reactions to abacavir.

Specific human leukocyte antigen (HLA) polymorphisms combined with certain drug administration strongly correlate with skin eruption. Abacavir hypersensitivity (AHS), which is strongly associated with HLA-B*57:01, is one of the most representative examples. Conventionally, HLA transmits immunological signals via interactions with T cell receptors on the cell surface. This study focused on HLA-mediated intracellular reactions in keratinocytes that might determine the onset of skin immunotoxicity by drug treatments. Abacavir exposure resulted in keratinocytes expressing HLA-B*57:01 exhibiting endoplasmic reticulum (ER) stress responses, such as immediate calcium release into the cytosol and enhanced HSP70 expression. In contrast, keratinocytes expressing HLA-B*57:03 (closely related to HLA-B*57:01) did not show these changes. This indicated that HLA-B*57:01 has a specific intracellular response to abacavir in keratinocytes in the absence of lymphocytes. Furthermore, abacavir exposure in HLA-B*57:01-expressing keratinocytes elevated the expression of cytokines/chemokines such as interferon-γ, interleukin-1β, and CCL27, and induced T lymphoblast migration. These effects were suppressed by ER stress relief using 4-phenylbutyrate (4-PB). HLA-B*57:01-transgenic mice also exhibited ER stress in epidermal areas following abacavir administration, and abacavir-induced skin toxicity was attenuated by the administration of 4-PB. Moreover, abacavir bound to HLA-B*57:01 within cells and its exposure led to HLA-B*57:01 protein aggregation and interaction with molecular chaperones in the ER of keratinocytes. Our results underscore the importance of HLA-mediated intracellular stress responses in understanding the onset of HLA-B*57:01-mediated AHS. We provide the possibility that the intracellular behavior of HLA is crucial for determining the onset of drug eruptions.

A protein-free vaccine stimulates innate immunity and protects against nosocomial pathogens.

Traditional vaccines are difficult to deploy against the diverse antimicrobial-resistant, nosocomial pathogens that cause health care-associated infections. We developed a protein-free vaccine composed of aluminum hydroxide, monophosphoryl lipid A, and fungal mannan that improved survival and reduced bacterial burden of mice with invasive blood or lung infections caused by methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, extended-spectrum beta-lactamase-expressing Escherichia coli, and carbapenem-resistant strains of Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The vaccine also conferred protection against the fungi Rhizopus delemar and Candida albicans. Efficacy was apparent by 24 hours and lasted for up to 28 days after a single vaccine dose, with a second dose restoring efficacy. The vaccine acted through stimulation of the innate, rather than the adaptive, immune system, as demonstrated by efficacy in the absence of lymphocytes that were abrogated by macrophage depletion. A role for macrophages was further supported by the finding that vaccination induced macrophage epigenetic alterations that modulated phagocytosis and the inflammatory response to infection. Together, these data show that this protein-free vaccine is a promising strategy to prevent deadly antimicrobial-resistant health care-associated infections.

Characterization of Immune Infiltrates Associated With Radiation Necrosis in the Setting of Brain Metastases Following Stereotactic Radiosurgery and Immunotherapy: A Retrospective Cohort Analysis.

Radiation necrosis (RN) is caused by vascular damage and brain parenchymal injury resulting in inflammation following radiotherapy (RT) for brain metastases. The impact of immunotherapy (IO) on the immune cellular microenvironment in patients' brain metastases is unknown. The objective of this study was to characterize the inflammatory microenvironment in the setting of RN compared to recurrent metastasis and determine whether IO treatment affects the cellular infiltrates. Adult patients with brain metastases from solid tumors who received both systemic IO and RT prior to resection of intracranial lesions were retrospectively analyzed. The resection either showed biopsy-proven RN or recurrent tumor. A group of patients who developed RN and were not on IO was reviewed as well. A total of 18 patients were categorized into one of three groups: necrosis, IO+RT; tumor, IO+RT; and necrosis, RT. Surgical specimens were stained for immune and inflammatory components and reviewed by a neuro-pathologist who remained blinded during the analysis. The presence or absence of lymphocytes, perivascular cuffs, plasma cells, macrophages, and fibrinoid vascular changes was characterized in a semiquantitative manner. The median age was 61.5 years (range 37-82 years). Seventy-seven percent of primary cancers were melanoma. Patients with RN were more likely to exhibit immune infiltrates compared to patients with recurrent metastasis. Limited analysis showed 100% of patients in "necrosis, IO+RT" had quantifiable cell counts; conversely, 83.3% of patients in "tumor, IO+RT" lacked quantifiable cell counts. Additionally, 83.3% of patients in "necrosis, RT" showed immune cells, including lymphocytes, macrophages, plasma cells, and cuffing. The immune microenvironment of brain metastasis following RT and IO showed higher levels of cell infiltrates in the RN setting versus the recurrent tumor setting. Patients who received prior IO compared to those with no IO had similar immune cell infiltrates adjacent to RN. Lower levels of immune cells in tumor recurrence following IO and RT raise the possibility that an environment lacking primed immune cells may decrease the efficacy of IO.

Epithelial-intrinsic defects in TGFβR signaling drive local allergic inflammation manifesting as eosinophilic esophagitis.

Allergic diseases are a global health challenge. Individuals harboring loss-of-function variants in transforming growth factor-β receptor (TGFβR) genes have an increased prevalence of allergic disorders, including eosinophilic esophagitis. Allergic diseases typically localize to mucosal barriers, implicating epithelial dysfunction as a cardinal feature of allergic disease. Here, we describe an essential role for TGFβ in the control of tissue-specific immune homeostasis that provides mechanistic insight into these clinical associations. Mice expressing a TGFβR1 loss-of-function variant identified in atopic patients spontaneously develop disease that clinically, immunologically, histologically, and transcriptionally recapitulates eosinophilic esophagitis. In vivo and in vitro, TGFβR1 variant-expressing epithelial cells are hyperproliferative, fail to differentiate properly, and overexpress innate proinflammatory mediators, which persist in the absence of lymphocytes or external allergens. Together, our results support the concept that TGFβ plays a fundamental, nonredundant, epithelial cell-intrinsic role in controlling tissue-specific allergic inflammation that is independent of its role in adaptive immunity.

Characterization of Immune Infiltrates Associated with Radiation Necrosis in the Setting of Brain Metastases Following Stereotactic Radiosurgery and Immunotherapy

<h3>Purpose/Objective(s)</h3> Radiation necrosis (RN) represents an inflammatory sequel and hyalinization secondary to radiotherapy (RT). The impact of immunotherapy on immune cellular microenvironment in patients with brain metastasis (BM) is unknown. The objective of this study was to characterize the inflammatory microenvironment in the setting of RN compared to recurrent tumor and determine whether immunotherapy treatment affects cellular infiltrates. <h3>Materials/Methods</h3> Adult patients with BM from solid tumors who received both systemic immunotherapy (IO) and radiotherapy (RT) who then underwent resection for progressively enlarging abnormality following IO+RT were retrospectively analyzed. A group of BM patients who developed RN confirmed by surgery and who did not receive IO was reviewed as control. Surgical specimens were stained for immune and inflammatory components and reviewed by a neuro-pathologist who remained blinded during the analysis. The presence or absence of lymphocytes, cuffing, plasma cells, macrophages, and fibrinoid were used as surrogates of immune infiltrate and were characterized in a semiquantitative manner. <h3>Results</h3> A total of 18 patients were categorized into 1 of 3 groups: (1) Necrosis, IO+RT (2) Tumor, IO+RT (3) Necrosis, RT. The median age was 61.5 years (range 37-82 years). 77% of primary cancers were melanoma. Review of surgical specimens demonstrated a higher but not statistically significant extent of immune infiltrates in the groups with RN when compared to the group with tumor recurrence. Higher lymphocytes, cuffing, and macrophages were found in "Necrosis, IO+RT" patients compared to "Tumor, IO+RT" patients (83.3% and 16.7%, respectively). Further analysis demonstrated 100% of "Necrosis, IO+RT" patients have quantifiable cell counts while 83.3% of "Tumor, IO+RT" patients do not have quantifiable cell counts. <h3>Conclusion</h3> The immune microenvironment of BM following radiotherapy and immunotherapy shows higher levels of cell infiltrates in the RN setting versus recurrent tumor setting. Lower level of presence of immune cells in tumor recurrence following IO+RT may suggest an environment lacking primed immune cells with implication to potential decreased efficacy in immunotherapy.

Leishmania major Strain-Dependent Macrophage Activation Contributes to Pathogenicity in the Absence of Lymphocytes.

ABSTRACTInfection of C57BL/6 wild-type mice with Leishmania major 5-ASKH or Friedlin strains results in relatively similar pathogenicity with self-healing lesions within weeks. Parasite clearance depends on nitric oxide production by activated macrophages in response to cytokines produced mainly by CD4+ Th1 cells. In contrast, C57BL/6 Rag2 knockout mice, which lack T and B lymphocytes, show distinct pathologies during infection with these strains. Despite of the similar parasite number, the 5-ASKH infection induced severe inflammation rather than the Friedlin. To determine the immunological factors behind this phenomenon, we infected C57BL/6 Rag2 knockout mice with these two strains and compared immune cell kinetics and macrophage activation status. Compared with the Friedlin strain, the 5-ASKH strain elicited increased pathology associated with the accumulation of CD11bhigh, Ly6Ghigh neutrophils by week four and increased the expression of macrophage activation markers. We then analyzed the differentially expressed transcripts in infected bone marrow-derived macrophages by RNA sequencing. It showed upregulation of multiple inflammatory transcripts, including Toll-like receptor 1/2 (TLR1/2), CD69, and CARD14, upon 5-ASKH infection. Our findings suggest that different L. major strains can trigger distinct macrophage activation, contributing to the disease outcome observed in the absence of lymphocytes but not in the presence of lymphocytes.IMPORTANCE Disease manifestations of cutaneous leishmaniasis (CL) range from self-healing cutaneous lesions to chronic forms of the disease, depending on the infecting Leishmania sp. and host immune protection. Previous works on mouse models of CL show the distinct pathogenicity of Leishmania major strains in the absence of lymphocytes. However, the mechanisms of this pathology remain uncovered. In the trial to understand the immunological process involved in lymphocyte-independent pathology, we have found a specific induction of macrophages by different L. major strains that affect their ability to mount innate responses leading to neutrophilic pathology when lymphocytes are ablated.

Modulation of tumor environment in colorectal cancer – could gut microbiota be a key player?

The treatment paradigm of neoplastic diseases has dramatically shifted with the introduction of immune checkpoint inhibitors (ICI). They induce a durable response in a wide variety of solid tumors, but this response depends on the infiltration of lymphocytes capable of recognizing and killing tumor cells. The primary predictor of intrinsic immune resistance to ICIs is the absence of lymphocytes in the tumor, the so-called “cold tumors”. Colorectal cancer (CRC) remains one of the most common and challenging cancer, but it is not traditionally considered a highly immunogenic tumor. In fact, immunotherapy showed a remarkable antitumoral activity only on a small subset of CRC patients – the ones with microsatellite instability-high/deficient DNA mismatch repair (MSI-H/dMMR). Most CRCs display a molecular microsatellite stability/proficient DNA mismatch repair (MSS/pMMR) profile, so strategies to improve tumor immunogenicity are crucial. Therefore, ongoing studies investigate new approaches to convert “cold” to “hot” tumors in MSS/pMMR CRCs. In addition, it has been described that gut microbiota influences tumor development and the host immune response. Hence, the microbiota may modulate the immune response, becoming a promising biomarker to identify patients who will benefit from ICIs. Future data will help to better understand microbiota mechanisms and their role in ICI efficacy. Precision medicine in cancer treatment could involve modulation of the microbiota through different strategies to improve tumor immunogenicity. In this review, we aim to present the potential relationship between gut microbiota and the modulation of the immune system and the hypothetical implications in CRC treatment, namely ICIs.

Systemic Inflammation Changes Association with Plan Tumor Volume and its Effects on Radiation Therapy Effects in Esophageal Cancer

Chemoradiation therapy of inoperable locally advanced esophageal cancer (LAEC), although improving outcomes of patients, still results in 50% of recurrence, which may be facilitated by the recruitment of circulating tumor cells to pro-inflammatory microenvironments in the absence of lymphocytes. Also, radiation can both suppress and stimulate the immune system. This study aimed to investigate the radiation induced-systemic inflammation changes in LAEC for early predicting treatment response to radiotherapy. Subjects consisted of 213 LAEC patients (median age of 66 years) who had received definitive thoracic radiotherapy with a median dose of 60Gy and 30fx, and 76% received concurrent chemotherapy. Peripheral blood was collected pre-RT, at week 2 during RT (mid-RT) and post-RT for each patient and analyzed by using automated flow cytometry. Neutrophil: lymphocyte ratio (NLR), platelet: lymphocyte ratio (PLR) were calculated for each complete blood count. Associations between plan tumor volumes (PTVs) with hematologic parameters pre-RT, mid-RT, post-RT and their changes during RT were assessed with Spearman correlation coefficients. Associations of the hematologic parameters with progression-free survival (PFS) of patients were analyzed by Cox proportional hazards regression analysis. With a median follow-up period of 36.3 months (range 24-44.8 months), median PFS was xx months. For all patients, the median PTV was 405.7±17.2 cc. Smaller PTVs were correlated with lower mid-RT NLR (r = 0.35; p = .000) and lower mid-RT PLR (r = 0.27; p = .000). On univariate analysis, Lower NLR (p = .04) and PLR (p = .01) at mid-RT and more decreasing in NLR (p = .001) and PLR (p = .004) at mid-RT were associated with longer PFS (Table 1). No significant predictive effects were shown in NLR or PLR at pre-RT or post-RT. Lower NLR and PLR during definitive radiotherapy were associated with smaller PTVs and longer PFS in LAEC. It indicated that peripheral inflammation following radiotherapy for LAEC may be a novel prognostic biomarker for radiotherapy response and further studies are needed to develop treatment strategies. Table 1. Univariable and multivariable Cox proportional hazards regression analysis.Abstract 3417; TableUnivariable analysisMultivariable analysisHR95%CIP valueHR95%CIP valueNLRpre-RT1.180.78-1.810.45NLRmid-RT1.591.03-2.440.04*0.640.30-1.370.25NLRpost-RT0.920.60-1.400.68NLRearlychange2.051.33-3.150.001*2.371.12-5.000.02*NLRchange0.860.56-1.330.50PLRpre-RT.760.61-1.430.76PLRmid-RT1.721.12-2.640.01*1.200.68-2.150.53PLRpost-RT1.240.81-1.900.32PLRearlychange1.901.23-2.920.004*1.440.82-2.540.21PLRchange1.310.85-2.000.22* statistically significant. Open table in a new tab

Ipilimumab and Its Derived EGFR Aptamer-Based Conjugate Induce Efficient NK Cell Activation against Cancer Cells.

The immune checkpoint CTLA-4 (cytotoxic T-lymphocyte-antigen 4), which inhibits the co-stimulatory CD28 signal on T cells, has been recently found expressed on other cell populations, such as tumor and natural killer (NK) cells. We tested for the first time the effects of ipilimumab, the human anti-CTLA4 mAb in clinical use, on these cells and found that it inhibits the growth of tumor cells expressing CTLA-4 also in the absence of lymphocytes, and efficiently activates NK cells, thus suggesting an important unexplored role of NK cells in ipilimumab-modulated immune responses. Interestingly, the epidermal growth factor receptor (EGFR) has been shown to play a key role in tumor cell escape from immune surveillance, and in cytotoxic T lymphocyte inhibition. Thus, we tested combinatorial treatments of ipilimumab with an anti-EGFR aptamer endowed with anti-tumor activity, and constructed for the first time a novel bispecific immunoconjugate, made up of these two compounds. The novel immunoconjugate binds to the target cells, induces the activation of lymphocytes, including NK cells, and inhibits the growth of tumor target cells more efficiently than the parental compounds, by strongly enhancing the cytotoxic activity of both human peripheral blood mononuclear cells and NK cells against tumor cells.

Cytomorphological findings in diagnosis of Warthin tumor

Background/aim To define the cytomorphologic findings leading to difficulties in diagnosis of Warthin tumors (WTs).Materials and methodsForty-eight histopathologically diagnosed WT patients who had fine needle aspiration cytology preoperatively were reevaluated for defining the presence or absence of lymphocytes, oncocytic cell layer, oncocytic cell papillae, granular debris background, mucoid background, macrophages, polymorphonuclear cells, mast cells, squamous-like cells, atypical vacuolated cytoplasmic cells, and giant cells.ResultsForty-seven tumors were in the parotid gland and one in the submandibular gland. There were 37 (77%) male and 11 (23%) female patients. Cytopathologically in 36 patients the diagnosis was benign neoplasm (WT); in 6, other benign entities; and in 6, suspicious for malignancy. The main characteristic cytomorphologic features of WTs were as follows: 92% lymphoid cells, 83% oncocytic cell layers, and 67% granular debris background. These percentages were 67%, 17%, and 17% in the benign cytology group and 67%, 50%, and 17% in the suspicious for malignancy group, respectively.ConclusionAbsence or lack of main features of WTs with or without presence of squamous-like cells, vacuolated cytoplasmic cells, and inflammatory reaction may cause diagnostic dilemma. The presence of the mast cells accompanied by epithelial tissue was striking for WT diagnosis.

Systemic Inflammation After Radiation Predicts Locoregional Recurrence, Progression, and Mortality in Stage II-III Triple-Negative Breast Cancer

Patients with triple-negative breast cancer experience high rates of recurrence after radiation, which may be facilitated by the recruitment of circulating tumor cells to proinflammatory microenvironments in the absence of lymphocytes. We hypothesized that patients with lymphopenia and elevated inflammatory hematologic markers after radiation therapy would have an increased risk of locoregional failure. With approval, we retrospectively studied a cohort of women treated with adjuvant radiation therapy for stage II-III triple-negative breast cancer. We analyzed the relationship between post-radiation therapy neutrophil:lymphocyte ratio (NLR) and locoregional recurrence by using Cox regression. One-hundred thirty patients met inclusion criteria, and median follow-up time was 7.6 years. Patients with an NLR ≥3 had a higher rate of locoregional failure (P = .04) and lower overall survival (P = .04). After adjusting for stage (hazard ratio [HR], 5.5; P < .0001) and neoadjuvant chemotherapy (HR, 2.5; P = .0162), NLR was highly predictive of locoregional failure (HR, 1.4; P = .0009). NLR was also highly predictive of overall survival (HR, 1.3; P = .0007) after adjustment for stage and neoadjuvant chemotherapy. Innate peripheral inflammation after radiation therapy for triple-negative breast cancer in an immunocompromised setting may be a novel prognostic biomarker for locoregional recurrence, progression, and survival. This finding supports preclinical studies of post-radiation therapy inflammation-mediated tumor progression. Further studies are needed to confirm this finding and develop treatment strategies.

Lymphocytes influence Leishmania major pathogenesis in a strain-dependent manner.

Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis and is caused by several species of Leishmania parasite. Clinical presentation of CL varies from a self-healing infection to a chronic form of the disease determined by the virulence of infecting Leishmania species and host immune responses to the parasite. Mouse models of CL show contradictory roles of lymphocytes in pathogenesis, while acquired immune responses are responsible for host protection from diseases. To reconcile the inconclusive roles of acquired immune responses in pathogenesis, we infected mice from various genetic backgrounds with two pathogenic strains of Leishmania major, Friedlin or 5ASKH, and assessed the outcome of the infections. Our findings showed that the genetic backgrounds of L. major determine the impact of lymphocytes for pathogenesis. In the absence of lymphocytes, L. major Friedlin induced the lowest inflammatory reaction and pathology at the site of infection, while 5ASKH infection induced a strong inflammatory reaction and severe pathology. Lymphocytes ameliorated 5ASKH mediated pathology, while it exacerbated pathology during Friedlin infection. Excess inflammatory reactions, like the recruitment of macrophages, neutrophils, eosinophils and production of pro-inflammatory cytokines, together with uncontrolled parasite growth in the absence of lymphocytes during 5ASKH infection may induce severe pathology development. Taken together our study provides insight into the impact of differences in the genetic background of Leishmania on CL pathogenesis.

Innate Immune Cells Are Regulated by Axl in Hypertensive Kidney

The balance between adaptive and innate immunity in kidney damage in salt-dependent hypertension is unclear. We investigated early renal dysfunction and the influence of Axl, a receptor tyrosine kinase, on innate immune response in hypertensive kidney in mice with lymphocyte deficiency (Rag1-/-). The data suggest that increased presence of CD11b+ myeloid cells in the medulla might explain intensified salt and water retention as well as initial hypertensive response in Rag1-/- mice. Global deletion of Axl on Rag1-/- background reversed kidney dysfunction and accumulation of myeloid cells in the kidney medulla. Chimeric mice that lack Axl in innate immune cells (in the absence of lymphocytes) significantly improved kidney function and abolished early hypertensive response. The bioinformatics analyses of Axl-related gene-gene interaction networks established tissue-specific variation in regulatory pathways. It was confirmed that complement C3 is important for Axl-mediated interactions between myeloid and vascular cells in hypertensive kidney. In summary, innate immunity is crucial for renal dysfunction in early hypertension, and is highly influenced by the presence of Axl.

Gut Microbiota Effects On Bone Density Are Dependent On T‐ and B‐ lymphocytes

Recent studies have shown that gut microbiota is an important regulator of bone density. In addition, it is well known that the gut microbiota can modulate the immune system. However, whether the effects of the gut microbiota on bone health involve the lymphocytes is still unknown. We hypothesized that modulation of gut microbiota will alter bone density, and this effect will be prevented in the absence of lymphocytes. To test our hypothesis, we treated Rag knockout (T and B lymphocyte deficient) mice and the corresponding C57BL/6J wild‐type mice (males, 12 weeks of age) with antibiotics (ABX) ampicillin (1g/L) and neomycin (0.5g/L) in the water for two weeks. After two weeks, mice received water without antibiotics for another 4 weeks to allow the repopulation of gut microbiota. Bone volume fractions (BVF) of the femur were analyzed using microcomputed tomography system. Fecal samples were used to confirm microbiota depletion after 2 weeks and repopulation after 6 weeks. Repopulation of the gut microbiota in the WT‐ABX group significantly decreased femoral trabecular BVF by 24% compared to the non‐ABX treated WT group (BVF/BW WT:.98, WT‐ABX:.74, n= 14–17). In the Rag KO mice, however, repopulation of the gut microbiota following ABX treatment did not affect femoral BVF compared to the respective control group (BVF/BW KO: 1.59, KO‐ABX: 1.49, n=7–11). Analysis of serum bone remodeling parameters indicated significantly lower serum osteocalcin levels (~ 37% of control levels) in WT‐ABX treated mice, while no changes were seen in the RAG‐KO group. Our study demonstrates that repopulation of the gut microbiota can be detrimental to the bone and that this effect is dependent on the T and B lymphocytes.Support or Funding InformationPorter Fellowship awarded to Naiomy‐Deliz Rios Arce. National Institutes of Health Grants RO1 DK101050 and RO1 AT007695‐01This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Abstract WMP79: Favorable Outcome of Stroke in Immunodeficient Mice is Preceded by Faster Normalization of T2 Relaxation

Introduction: Despite the success of rtPA and thrombectomy stroke continues to be a major disease burden to our society. Preventing secondary brain injury after stroke, given the broad therapeutic window, has gained increasing interest. It has been hypothesized that immunological processes substantially contribute to secondary brain damage. Indeed, the outcome of stroke in immunodeficient animals is more favorable compared to that in their immunocompetent counterparts. Here, we followed the evolution of stroke in the presence vs. absence of lymphocytes using serial MRI and T2 measurements. Methods: Adult immunodeficient rag2 -/- mice (n=6) and immunocompetent BALB/c mice (n=6) were subjected to stroke by intracerebral injection of 0.5 μl of 5 mM ouabain. Brain T2 relaxation times were measured using an 11.7T scanner at 1, 5, and 16 days following stroke induction. Post-mortem analysis of tissue sections included H&amp;E and immunohistochemical staining for myelin basic protein, neurofilament, CD8, and CD68. Results: While the increase in T2 values was identical for immunocompetent and immunodeficient animals one day post-stroke (70.88±4.58 vs. 69.88±1.78 ms, respectively, p=0.72), the normalization of the T2 relaxation time (“fogging effect”) proceeded faster in immunodeficient animals over the next few days. Over five days, T2 relaxation times decreased in both groups, but it was significantly shorter in immunodeficient animals compared to immunocompetent animals (41.88±3.68 vs. 59.91±14.95 ms, respectively; p&lt;0.001). On day 16, the T2 relaxation time decreased further in both groups and the difference between infarcted area in immunodeficient and immunocompetent animals as well as healthy tissue was no longer observed. Post-mortem analysis revealed a better preservation of infarcted tissue in immunodeficient animals. Conclusions: In immunodeficient rag2 -/- mice, the restoration of T2 relaxation times in the brain is faster and translates into less profound destruction of brain tissue within stroke lesions. We hypothesize that T2 relaxation time can be used for assessment of immunotherapies aimed at the reduction of secondary brain injury in stroke victims.

Different Biological Characteristics of Macrophages from BALB/c Mice and Severe Combined Immunodeficient Mice.

Our previous research has found that absence of lymphocytes during development may affect innate activity of immune cells. To better understand the effect of lymphocyte defects on macrophages during development, we compared the biological characteristics of peritoneal macrophages (PMa) from BALB/c and severe combined immunodeficient (SCID) mice. Cytokines such as TNF-α, IL-6, and IL-10 produced by PMa and mRNA of those cytokines of PMa, phagocytosis of chicken red cells by PMa, and cell surface markers of PMa from BALB/c and SCID mice were tested. LPS was used as the stimulator. Compared with PMa from BALB/c mice, PMa from SCID mice produced more TNF-α, IL-6, and less IL10 after LPS stimulation in vitro and exhibited decreased phagocytosis in vivo or in vitro. The MFI of cell surface markers, including TLR4, MHC-II and CD80/CD86, on PMa increased markedly after LPS injection in vivo, but was not significantly different between the two mouse strains. Lymphocyte defects during development lead to increased inflammatory potential and decreased phagocytosis of PMa. If BALB/c and SCID mice are used as models to compare differences in infections and inflammation, the different biological characteristics of macrophages should be considered.

Spiradenocylindroma of skin: A hybrid tumor

Spiradenocylindroma is a rare occurrence where tumor has histological features of both spiradenoma and cylindroma in single nodular lesion. Due to dual histomorphological features in a single lesion, it is considered as a hybrid tumor. We describe a case of spiradenocylindroma in a 70-year old female. Spiradenocylindroma presents a diagnostic challenge to the histopathologist because both tumors share some common features; however, the presence and absence of lymphocytes are important for differentiation.

Differential gene expression following TLR stimulation in rag1-/- mutant zebrafish tissues and morphological descriptions of lymphocyte-like cell populations.

In the absence of lymphocytes, rag1-/- mutant zebrafish develop protective immunity to bacteria. In mammals, induction of protection by innate immunity can be mediated by macrophages or natural killer (NK) cells. To elucidate potential responsive cell populations, we morphologically characterized lymphocyte-like cells (LLCs) from liver, spleen and kidney hematopoietic tissues. In fish, these cells include NK cells and Non-specific cytotoxic cells (NCCs). We also evaluated the transcriptional expression response of select genes that are important indicators of NK and macrophage activation after exposure to specific TLR ligands. The LLC cell populations could be discriminated by size and further discriminated by the presence of cytoplasmic granules. Expression levels of mx, tnfα, ifnγ, t-bet and nitr9 demonstrated dynamic changes in response to intra-coelomically administered β glucan (a TLR2/6 ligand), Poly I:C (a TLR3 ligand) and resiquimod (R848) (a TLR7/8 ligand). Following TLR 2/6 stimulation, there was a greater than 100 fold increase in ifnγ in liver, kidney and spleen and moderate increases in tnfα in liver and kidney. TLR3 stimulation caused broad up regulation of mx, down-regulation of tnfα in kidney and spleen tissues and up regulation of nitr9 in the kidney. Following TLR 7/8 stimulation, there was a greater than 100 fold increase in ifnγ in liver and kidney and t-bet in liver. Our gene expression findings suggest that LLCs and macrophages are stimulated following β glucan exposure. Poly I:C causes type I interferon response and mild induction of LLC in the kidney and R-848 exposure causes the strongest LLC stimulation. Overall, the strongest NK like gene expression occurred in the liver. These differential effects of TLR ligands in rag1-/- mutant zebrafish shows strong NK cell-like gene expression responses, especially in the liver, and provides tools to evaluate the basis for protective immunity mediated by the innate immune cells of fish.

고슴도치 구강유두종

Here we describe the histological lesion of a viral fibro-papilloma in a hedgehog. After surgical removal from maxilla, the solitary swollen mass was round to oval, yellowish with rough surface and measuring 6×3×2mm approximately. The tumor mass was submitted to the laboratory of pathology, college of veterinary medicine, Kyungpook National University for pathological diagnosis. Pathological examination of the tumor was established, the tumor was described grossly and sample was trimmed, sectioned and routinely prepared for histopathological evaluation. The tumor mass was diagnosed as viral fibro-papilloma, as the histological picture showed characteristic features of warts caused by papillomaviruses. The tumor characterized by thickening of the stratum spinosum (acanthosis) and basale, koilocytosis, intra-nuclear inclusion bodies in keratinocytes and fibrosis of submucosa. Further, viral inclusion bodies were demonstrated by Machiavello stain giving red color to the nuclei. No lymphocytes that responsible for regression of the wart could be detected, suggesting the poor possibility of spontaneous regression of the tumor. Papillomatosis is a disease of young animals, but in our case the infected Hedgehog was 5 years old, that maybe due to an impaired immune system, which is also shown by absence of lymphocytes. To the best knowledge of the author, this case presents the first report of viral fibropapillomatosis in Hedgehog.