Stromal cell and B cell dialogue potentiates IL-33-enriched lymphoid niches to support eosinophil recruitment and function during type 2 immunity.

Eosinophils are involved in host protection against multicellular organisms. However, their recruitment to the mesenteric lymph node (mLN) during type 2 immunity is understudied. Our results demonstrate that eosinophil association with lymphoid stromal niches constructed by fibroblastic reticular cells (FRCs) and lymphatic endothelial cells is diminished in mice selectively lacking interleukin (IL)-4Rα or lymphotoxin-ß (LTß) expression on B cells. Furthermore, eosinophil survival, activation, and enhanced Il1rl1 receptor expression are driven by stromal cell and B cell dialogue. The ligation of lymphotoxin-ß receptor (LTßR) on FRCs improves eosinophil survival and significantly augments IL-33 expression and eosinophil homing to the mLN, thus confirming the significance of lymphotoxin signaling for granulocyte recruitment. Eosinophil-deficient ΔdblGATA-1 mice show diminished mLN expansion, reduced interfollicular region (IFR) alarmin expression, and delayed helminth clearance, elucidating their importance in type 2 immunity. These findings provide insight into dialogue between stromal cells and B cells, which govern mLN eosinophilia, and the relevance of these mechanisms during type 2 immunity.

Influence of Photodynamic Therapy with Subsequent Surgical Treatment of Experimental Breast Cancer on Quantitative Changes in miRNAs in a Mesenteric Lymph Node.

In female Wistar rats with breast cancer, quantitative changes of pro-oncogenic miRNAs (miR-21, -27a, and -221) and tumor-suppressive miR-429 in the mesenteric lymph node were assessed after photodynamic therapy for breast cancer and after photodynamic therapy followed surgical treatment. The level of pro-oncogenic miR-221 in the mesenteric lymph node decreased, and the level of pro-oncogenic miR-21 increased after photodynamic therapy for breast cancer followed by surgical treatment in comparison with the corresponding parameters after photodynamic therapy alone. The content of tumor-suppressive miR-429 remained reduced, as in the group of animals receiving photodynamic therapy alone.

Mesenteric Castleman Disease Mimicking Neuroendocrine Tumor.

Castleman disease (CD) is a benign lymphoproliferative disorder of unknown etiology, which can involve any part of the body. CD can involve a single lymph node (unicentric) or multiple lymph nodes (multicentric) of which unicentric CD is the most common type. The unicentric CD is usually localized, asymptomatic, and often appears as an incidental mass on radiographs, whereas multicentric CD is characterized by systemic involvement. Mesenteric involvement of CD is very rare. In this article, we present a case of the unicentric CD of small bowel mesentery, which mimicked a neuroendocrine tumor preoperatively.

Effects of the commensal microbiota on spleen and mesenteric lymph node immune function: investigation in a germ-free piglet model.

Commensal microbial-host interaction is crucial for host metabolism, growth, development, and immunity. However, research on microbial-host immunity in large animal models has been limited. This study was conducted to investigate the effects of the commensal microbiota on immune function in two model groups: germ-free (GF) and specific-pathogen-free (SPF) piglets. The weight and organ index of the spleen of the GF piglet were larger than those in the SPF piglet (P < 0.05). The histological structure of the red pulp area and mean area of germinal centers were larger in the SPF piglet than in the GF piglet (P < 0.05), whereas the areas of staining of B cells and T cells in the spleen and mesenteric lymph nodes (MLNs) were lower in the GF piglet (P < 0.05). We identified immune-related genes in the spleen and MLNs using RNA sequencing, and used real-time quantitative PCR to analyze the expression of core genes identified in gene set enrichment analysis. The expression levels of genes in the transforming growth factor-ß/SMAD3 signaling pathway, Toll-like receptor 2/MyD88/nuclear factor-κB signaling pathway, and pro-inflammatory factor genes IL-6 and TNF-α in the spleen and MLNs were higher in the SPF piglet and in splenic lymphocytes compared with those in the GF and control group, respectively, under treatment with acetic acid, propionic acid, butyric acid, lipopolysaccharide (LPS), or concanavalin A (ConA). The abundances of plasma cells, CD8++ T cells, follicular helper T cells, and resting natural killer cells in the spleen and MLNs were significantly greater in the SPF piglet than in the GF piglet (P < 0.05). In conclusion, the commensal microbiota influenced the immune tissue structure, abundances of immune cells, and expression of immune-related pathways, indicating the importance of the commensal microbiota for spleen and MLNs development and function. In our study, GF piglet was used as the research model, eliminating the interference of microbiota in the experiment, and providing a suitable and efficient large animal research model for exploring the mechanism of "microbial-host" interactions.

Enhanced Proteomic Coverage in Tissue Microenvironment by Immune Cell Subtype Library-Assisted DIA-MS.

Immune cells that infiltrate the tumor microenvironment (TME) play crucial roles in shaping cancer development and influencing clinical outcomes and therapeutic responses. However, obtaining a comprehensive proteomic snapshot of tumor-infiltrating immunity in clinical specimens is often hindered by small sample amounts and a low proportion of immune infiltrating cells in the TME. To enable in-depth and highly sensitive profiling of microscale tissues, we established an immune cell-enriched library-assisted strategy for data-independent acquisition mass spectrometry (DIA-MS). Firstly, six immune cell subtype-specific spectral libraries were established from sorted cluster of differentiation markers, CD8+, CD4+ T lymphocytes, B lymphocytes, natural killer cells, dendritic cells, and macrophages in murine mesenteric lymph nodes (MLNs), covering 7815 protein groups with surface markers and immune cell-enriched proteins. The feasibility of microscale immune proteomic profiling was demonstrated on 1 µg tissue protein from the tumor of murine colorectal cancer (CRC) models using single-shot DIA; the immune cell-enriched library increased coverage to quantify 7419 proteins compared to directDIA analysis (6978 proteins). The enhancement enabled the mapping of 841 immune function-related proteins and exclusive identification of many low-abundance immune proteins, such as CD1D1, and CD244, demonstrating high sensitivity for immune landscape profiling. This approach was used to characterize the MLNs in CRC models, aiming to elucidate the mechanism underlying their involvement in cancer development within the TME. Even with a low percentage of immune cell infiltration (0.25-3%) in the tumor, our results illuminate downregulation in the adaptive immune signaling pathways (such as C-type lectin receptor signaling, and chemokine signaling), T cell receptor signaling, and Th1/Th2/Th17 cell differentiation, suggesting an immunosuppressive status in MLNs of CRC model. The DIA approach using the immune cell-enriched libraries showcased deep coverage and high sensitivity that can facilitate illumination of the immune proteomic landscape for microscale samples.

Unilateral gluteal myositis as a unique presentation in mesenteric Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease (KFD) is a self-limiting disease, characterised by fever and cervical lymphadenopathy. Lymphadenopathy without cervical lymph node involvement is rare and may mimic lymphoma. Although KFD can be associated with extranodal involvement, muscle involvement has not been reported. Herein, we report a novel case of unilateral gluteal myositis associated with mesenteric KFD in a patient who presented with persistent fever and right hip pain. Radiological imaging revealed an inflammatory lesion on the right gluteal muscle and multiple enlarged abdominal lymph nodes. No cervical lymphadenopathy was observed. A mesenteric lymph node biopsy was performed, and the histopathological findings led to a diagnosis of KFD. By day 29, the patient's body temperature gradually returned to normal without any therapeutic intervention. Follow-up radiological imaging showed resolution of the gluteal lesion and a significant decrease in abdominal lymph node size. Considering the clinical course, the unilateral myositis may have developed as an extranodal involvement of KFD. Even if the clinical findings appear unrelated to those of KFD, a differential diagnosis that includes KFD should be considered in patients with unknown origin of fever.

Effects of rumen cannulation combined with different pre-weaning feeding intensities on the intestinal, splenic and thymic immune system in heifer calves several month after surgery.

Fistulation is a helpful procedure in animal nutritional research and also common practise in human medicine. However, there are indications that alterations in the upper gastrointestinal tract contribute to intestinal immune modulations. The present study aimed to investigate effects of a rumen cannulation in week 3 of life on the intestinal and tissue specific immune system of 34-week old heifers. Nutrition influences the development of the neonatal intestinal immune system to a high extent. Therefore, rumen cannulation was investigated in combination with different pre-weaning milk feeding intensities (20% (20MR) vs. 10% milk replacer feeding (10MR). Heifers of 20MR without rumen cannula (NRC) showed higher cluster of differentiation (CD)8+ T cell subsets in mesenteric lymph nodes (MSL) compared to heifers with rumen cannula (RC) and 10MRNRC heifers. CD4+ T cell subsets in jejunal intraepithelial lymphocytes (IELs) were higher in 10MRNRC heifers compared to 10MRRC heifers. CD4+ T cell subsets in ileal IELs were lower and CD21+ B cell subsets were higher in NRC heifers compared to RC heifers. CD8+ T cell subsets in spleen tended to be lower in 20MRNRC heifers compared to all other groups. Splenic CD21+ B cell subsets were higher in 20MRNRC heifers compared to RC heifers. Splenic toll like receptor (TLR) 6 expression was increased and IL4 expression tended to be increased in RC heifers than NRC heifers. Splenic TLR2, 3 and 10 gene expression was higher in 20MR compared to 10MR heifers. Jejunal prostaglandin endoperoxide synthase 2 expression was higher in RC heifers than NRC heifers, and MUC2 expression tended to increase in 20MR heifers compared to 10MR heifers. In conclusion, rumen cannulation modulated T and B cell subsets in the down streaming gastrointestinal tract and spleen. Pre-weaning feeding intensity seemed to affect intestinal mucin secretion and T and B cell subsets in MSL, spleen and thymus until several month later. Interestingly, in MSL, spleen and thymus the 10MR feeding regime evoked similar modulations of T and B cell subsets like rumen cannulation.

Characteristics of Th9 cells in Schistosoma japonicum-infected C57BL/6 mouse mesenteric lymph node.

Interleukin 9 (IL-9) is an effective cytokine secreted by newly defined Th9 cells, which is involved in allergic and infectious diseases. In this study, lymphocytes were isolated from mesenteric lymph node (MLN), spleen, liver, lung, and Peyer's patches (PP) of C57BL/6 mice 5-6 weeks after S. japonicum infection, intracellular cytokine staining was done to detect the percentage of IL-9-producing CD4+ T cells. The qPCR and ELISA were used to verify the content of IL-9 in MLN. The population of IL-9-producing lymphocyte subset was identified by FACS. In addition, the dynamic changes and cytokine profiles of Th9 cells in the MLN of infected mice were detected by FACS. ELISA was used to detect IL-9 induced by soluble egg antigen (SEA) from isolated lymphocytes in mouse MLN. The results showed that the percentage of IL-9-secreting Th9 cells in the MLN of the infected mouse was higher than that in the spleen, liver, lung, or PP. Though CD8+ Tc cells, NKT cells, and γδT cells could secrete IL-9, CD4+ Th cells were the main source of IL-9 in S. japonicum-infected C57BL/6 mice (P < 0.05). The percentage of Th9 cells in MLN of infected mouse increased from week 3-4, and reached a peak at week 5-6, then began to decrease from week 7-8 (P < 0.05). Moreover, Th9 cells could also secrete a small amount of IL-4, IFN-γ, IL-5, and IL-10. Our results suggested a higher percentage of Th9 cells was induced in the MLN of S. japonicum-infected mice, which might play an important role in the early stage of S. japonicum-induced disease.

N-Acetylcysteine Administration Improves the Redox and Functional Gene Expression Levels in Spleen, Mesenteric Lymph Node and Gastrocnemius Muscle in Piglets Infected with Porcine Epidemic Diarrhea Virus.

Our previous study reported that N-acetylcysteine (NAC) administration improved the function of intestinal absorption in piglets infected with porcine epidemic diarrhea virus (PEDV). However, the effects of NAC administration on the functions of other tissues and organs in PEDV-infected piglets have not been reported. In this study, the effects of NAC on the liver, spleen, lung, lymph node, and gastrocnemius muscle in PEDV-infected piglets were investigated. Thirty-two 7-day-old piglets with similar body weights were randomly divided into one of four groups: Control group, NAC group, PEDV group, and PEDV+NAC group (eight replicates per group and one pig per replicate). The trial had a 2 × 2 factorial design consisting of oral administration of 0 or 25 mg/kg body weight NAC and oral administration of 0 or 1.0 × 104.5 TCID50 PEDV. The trial lasted 12 days. All piglets were fed a milk replacer. On days 5-9 of the trial, piglets in the NAC and PEDV + NAC groups were orally administered NAC once a day; piglets in the control and PEDV groups were orally administered the same volume of saline. On day 9 of trial, piglets in the PEDV and PEDV+NAC groups were orally administrated 1.0 × 104.5 TCID50 PEDV, and the piglets in the control and NAC groups were orally administrated the same volume of saline. On day 12 of trial, samples, including of the liver, spleen, lung, lymph node, and gastrocnemius muscle, were collected. PEDV infection significantly increased catalase activity but significantly decreased the mRNA levels of Keap1, Nrf2, HMOX2, IFN-α, MX1, IL-10, TNF-α, S100A12, MMP3, MMP13, TGF-ß, and GJA1 in the spleens of piglets. NAC administration ameliorated abnormal changes in measured variables in the spleens of PEDV-infected piglets. In addition, NAC administration also enhanced the antioxidant capacity of the mesenteric lymph nodes and gastrocnemius muscles in PEDV-infected piglets. Collectively, these novel results revealed that NAC administration improved the redox and functional gene expression levels in the spleen, mesenteric lymph nodes, and gastrocnemius muscle in PEDV-infected piglets.

Fecal and Tissue Microbiota Are Associated with Tumor T-Cell Infiltration and Mesenteric Lymph Node Involvement in Colorectal Cancer.

Colorectal cancer (CRC) is associated with alterations of the fecal and tissue-associated microbiome. Preclinical models support a pathogenic role of the microbiome in CRC, including in promoting metastasis and modulating antitumor immune responses. To investigate whether the microbiome is associated with lymph node metastasis and T cell infiltration in human CRC, we performed 16S rRNA gene sequencing of feces, tumor core, tumor surface, and healthy adjacent tissue collected from 34 CRC patients undergoing surgery (28 fecal samples and 39 tissue samples). Tissue microbiome profiles-including increased Fusobacterium-were significantly associated with mesenteric lymph node (MLN) involvement. Fecal microbes were also associated with MLN involvement and accurately classified CRC patients into those with or without MLN involvement. Tumor T cell infiltration was assessed by immunohistochemical staining of CD3 and CD8 in tumor tissue sections. Tumor core microbiota, including members of the Blautia and Faecalibacterium genera, were significantly associated with tumor T cell infiltration. Abundance of specific fecal microbes including a member of the Roseburia genus predicted high vs. low total and cytotoxic T cell infiltration in random forests classifiers. These findings support a link between the microbiome and antitumor immune responses that may influence prognosis of locally advanced CRC.

Usefulness of intraoperative monitoring for mesenteric lymph node metastasis in transplanted free jejunum.

We herein report a rare case of a patient with hypopharyngeal squamous cell carcinoma (SCC) who presented with recurrent metastasis in the mesenteric lymph node of a transplanted jejunum. Removal of the metastatic lymph node required resection of the nutrient vessels which risked the current state of the transplanted jejunum. Importantly, although the nutrient vessels were resected, the jejunum did not become necrotic. This case and another similar case indicate that it may be possible to predict the viability of a transplanted jejunum where jejunal nutrient vessels must subsequently be resected. Key indicators for jejunal survival include determining jejunal blood flow by intraoperative indocyanine green fluorescence imaging, confirming good jejunal color and observation of peristaltic movement by intraoperative blood flow blockage of nutrient vessels. In conclusion, if intraoperative indocyanine green fluorescence imaging in the entire jejunum can be confirmed, there is a high possibility that the jejunum can be well preserved. The clinical presentation and clinical course are described with a proposed new schema of the resectable site of the transplanted jejunal mesentery.

Is complete mesocolic excision or total mesorectal excision necessary during cytoreductive surgery in ovarian peritoneal carcinomatosis with colonic involvement?

INTRODUCTION: Cytoreductive surgery (CRS) and intraperitoneal chemotherapy are effective in the treatment of ovarian peritoneal carcinomatosis (OPC). Colon resection is often required to achieve maximal cytoreduction during CRS. The success of complete mesocolic excision (CME) and total mesorectal excision (TME) in the surgical treatment of primary colorectal tumors is well-known. Our study aimed to investigate the factors affecting mesocolic lymph node metastasis (MLNM) and the contribution of CME/TME techniques to maximal cytoreduction in patients diagnosed with ovarian peritoneal carcinomatosis (OPC) with colon metastasis. PATIENTS AND METHODS: Between 2004-2020, 30 patients who underwent colorectal resection with CME/TME techniques due to OPC-related colon metastasis were retrospectively analyzed. RESULTS: The median age of patients was 61 (33-86). Six (20%) patients underwent total colectomy, 7 (23%) subtotal colectomy, 6 (20%) right hemicolectomy, 4 (13%) left hemicolectomy, and 7 (23%) rectosigmoid resection. Histopathological diagnosis was high-grade serous carcinoma in 29 (97%) patients, and malignant mixed Mullerian tumor in 1 (3%) patient. MLNM was detected in 17 (56%) of 30 patients. There was a significant relationship between MLNM and pelvic and para-aortic lymph node metastasis (PALNM) (p = 0.009) and lymphovascular invasion in primary ovarian tumors (p = 0.017). There was no significant relationship between MLNM and depth of colonic invasion (p = 0.463), histological grade (p = 0.711), and primary/secondary surgery (p = 0.638). MLNM was seen in 8 (47%) of 17 patients with only serosal invasion. CONCLUSION: A high rate of MLNM can be seen in OPC-induced colon metastasis regardless of the degree of colon wall invasion. In patients with PALNM, the frequency of MLNM increases. We believe that if colon resection is to be performed in OPC, a colectomy should be performed by CME/TME principles to achieve maximal cytoreduction.

Small bowel fistula with colorectal cancer and mesenteric lymph node metastasis: a report of two cases.

A 65-year-old man presented to our hospital with complaints of diarrhea. Computed tomography showed a fistula with the small intestine, and a single incision laparoscopic low anterior resection for rectum with D3 dissection and partial resection of the small intestine were performed. Lymph node dissection, including a part of the inflow vessel area, was also performed because lymph node swelling was observed in the mesentery of the small intestine around the fistula. Histopathological analysis revealed that the lymph nodes in the small intestine were positive for metastasis. The patient was a 61-year-old woman who presented to our hospital with a chief complaint of diarrhea. A partial resection of the small intestine, including resection of the left hemicolectomy and lymph node dissection around the fistula, was performed at laparotomy. Histopathological examination revealed numerous lymph node metastases in the small intestinal mesentery.

Salvage surgery for mesenteric lymph node metastasis by resection of the first jejunal flap and reconstruction with the second jejunal flap.

We report a case of a second free jejunal transfer to treat metastasis in the mesenteric lymph node of the first jejunal flap. A 73-year-old man underwent total pharyngolaryngectomy, bilateral neck dissection, and free jejunal transfer for recurrent hypopharyngeal cancer [left pyriform sinus, pT2N0, moderately differentiated squamous cell carcinoma (SCC)] after radiotherapy. Seven years post-surgery, he underwent transoral videolaryngoscopic surgery for oropharyngeal cancer (soft palate, pT1N0, well-differentiated SCC). Ten years after the first jejunal transfer, metastasis was found in the mesenteric lymph node surrounding the jejunal flap's vascular pedicle. Under general anesthesia, resection of the first jejunum including the affected lymph node, and second jejunal transfer were performed. Lymph node pathological examination revealed poorly differentiated SCC, compatible with pharyngeal cancer metastasis. After neck dissection and jejunal flap transfer, lymphatic collateral pathways toward the flap's mesenteric lymph node might form. Possibly, hypopharyngeal or oropharyngeal cancer metastasized via this pathway.

Characteristics of intestinal-related lymphoid hyperplasia in children and its correlation with intussusception of children.

BACKGROUND: Primary intussusception in children is a common acute abdominal disease. The cause of this disease is still not fully understood. Many articles have reported that children with intussusception are often accompanied by hyperplasia of mesenteric lymph nodes and submucosal lymphoid tissue of the terminal ileum. Therefore, hyperplasia of intestinal-associated lymphoid tissue (mesenteric lymph nodes and submucosal lymphoid tissue of the intestinal tract) may be one of the main causes of intussusception. However, the characteristics and differences of intestinal-associated lymphoid tissues in healthy children and children with intussusception at different ages have not been reported. In addition, the relationship between mesenteric lymph nodes and intestinal submucosal lymphatic tissue also needs to be further understood. METHODS: 73 patients with intussusception during the recovery phase who were treated in our hospital from October 2019 to October 2021 were collected as the observation group, while 101 children with healthy physical examination or diseases unrelated to intestinal lymphoid hyperplasia were collected as the control group. They were divided into different age groups of 1-6 months, 7-12 months, 13-18 months, 19-24 months, 25-36 months, 3-4 years, 5-6 years, and 7-8 years old. Ultrasonography was used to explore and scan mesenteric lymph nodes in fixed areas of the right lower abdomen and around the umbilicus. The size (cm3) and number (n) of detectable lymph nodes in each region were recorded and calculated, and the total mesenteric lymph node volume (cm3) of the right lower abdomen (RLTMLNV) and periumbilical region (PTMLNV) was calculated, respectively. The total mesenteric lymph node volume of each region in different ages of the two groups was analyzed. RESULTS: (1) There were significant differences between the control group and the observation group in the right lower abdominal total mesenteric lymph nodes volume (RLTMLNV) and the periumbilical total mesenteric lymph nodes volume (PTMLNV) (P = 0.001). The mesenteric lymph nodes in the observation group showed severe hyperplasia. (2) Children with intussusceptions are usually accompanied by severe mesenteric lymphoid hyperplasia. The mean volume value of RLTMLNV was greater than that of PTMLNV. Especially within 2 years of age, the mean value of RLTMLNV was significantly higher than that of PTMLNV with statistical significance (P < 0.05). (3) In normal children (control group), lymph nodes in the right lower abdomen and periumbilical area showed low hyperplasia, and there was a significant difference between age groups of < 2 years old and 2-8 years old (p = 0.001). In the children with intussusception (observation group), the hyperplasia of mesenteric lymph nodes in the right lower abdomen and around the umbilicus was severe. There was no significant difference in the proliferation of mesenteric lymphoid tissue among different age groups in the right lower abdomen (P = 0.834). There was also no significant difference in hyperplasia of periumbilical mesenteric lymphoid tissue among different age groups (P = 0.097). CONCLUSIONS: Our research shows: (1) The occurrence of primary intussusception in children is related to the hyperplasia of intestinal-associated lymphoid tissue. (2) Children with intussusceptions were usually accompanied by severe mesenteric lymphoid hyperplasia. The mesenteric lymphoid hyperplasia was more evident in the right lower abdominal ileocecal area than in the periumbilical area before 2 years of age. RLTMLNV has better predictability of intussusception than PTMLNV. The occurrence of intussusceptions was more closely related to the hyperplasia of intestinal-associated lymphoid tissue in the right lower abdomen. (3) Normal children showed a low degree of mesenteric lymphoid hyperplasia before 2 years old, moderate hyperplasia after 2 years old, and mesenteric lymphoid hyperplasia in the right lower abdominal ileocecal area was basically the same as the periumbilical area. The lymphatic tissue of the right lower abdomen and periumbilical mesentery in children with intussusceptions showed severe hyperplasia, and there were no significant differences among different age groups.

Immune State Conversion of the Mesenteric Lymph Node in a Mouse Breast Cancer Model.

Secondary lymphoid tissues, such as the spleen and lymph nodes (LNs), contribute to breast cancer development and metastasis in both anti- and pro-tumoral directions. Although secondary lymphoid tissues have been extensively studied, very little is known about the immune conversion in mesenteric LNs (mLNs) during breast cancer development. Here, we demonstrate inflammatory immune conversion of mLNs in a metastatic 4T1 breast cancer model. Splenic T cells were significantly decreased and continuously suppressed IFN-γ production during tumor development, while myeloid-derived suppressor cells (MDSCs) were dramatically enriched. However, T cell numbers in the mLN did not decrease, and the MDSCs only moderately increased. T cells in the mLN exhibited conversion from a pro-inflammatory state with high IFN-γ expression to an anti-inflammatory state with high expression of IL-4 and IL-10 in early- to late-stages of breast cancer development. Interestingly, increased migration of CD103+CD11b+ dendritic cells (DCs) into the mLN, along with increased (1→3)-ß-D-glucan levels in serum, was observed even in late-stage breast cancer. This suggests that CD103+CD11b+ DCs could prime cancer-reactive T cells. Together, the data indicate that the mLN is an important lymphoid tissue contributing to breast cancer development.

Mesenteric lymph node abscesses due to Escherichia coli in a cat.

A 3-year-old, castrated male mixed-breed cat presented with an almost 2-year history of chronic loose stools. On radiography and ultrasound examination, there were two masses in the centre of the abdomen. Contrast-enhanced computed tomography revealed that the masses were enlarged mesenteric lymph nodes with fluid accumulation. Percutaneous lesion drainage yielded pus-like fluid. Fluid cytology revealed numerous neutrophils and Gram-negative rods. Pus culture identified Escherichia coli as the causative organism. Consequently, mesenteric lymph node abscesses were definitively diagnosed. Since computed tomography showed that the abscesses adhered to the surrounding tissues, it was difficult to remove them surgically. With drainage and antimicrobial therapy, the mesenteric lymph nodes gradually decreased in size. However, loose stools persisted. The cat's diet was changed to a hydrolysed diet, and the clinical symptoms improved, suggesting food-responsive enteropathy. This may be an underlying disease of lymph node abscesses. Lymph node abscesses limited to the mesenteric lymph nodes rarely occur in veterinary medicine, and this is the first report in cats.

Immunocyte Populations Observed from Birth to Weaning in Blood, Spleen and Mesenteric Lymph Nodes of Piglets.

Susceptibility to pathogen infections and efficacy of vaccination highly depend on the immune status of the piglet. Here, we measured immunocytes in piglets from birth to weaning to elucidate how immunocyte populations change during development and are affected by weaning. Crossbred piglets were used. Suckling piglets were euthanized at 1, 7, 14, 21, 28 or 35 days old (3~4 piglets at each time point). In addition, seven piglets were weaned at 21 days old, with four being euthanized at 28 days old and the remaining at 35 days old. Piglet carcasses were dissected, and blood, mesenteric lymph nodes (MLN) and spleen were sampled. In total, seven antibodies were used to stain the immunocyte population. Dynamics of myeloid (CD3−SWC3+CD16+), natural killer (NK; CD3−SWC3−CD16+), killer T (CD3+CD8+), helper T (CD3+CD4+) and B (CD3−CD21+) cells were analyzed. Percentage of innate immunity cells such as myeloid cells declined (p < 0.05) from the first day after birth. In contrast, percentage of NK cells increased in piglets while they were still suckling. Killer T, helper T, and B cell populations increased around 2~3 weeks after birth. No significant differences in the populations of the evaluated cell types were observed between suckling and weaned piglets at least for 14 days post weaning.

Isolation of CD35+ follicular dendritic cells and its role in the differentiation from B cells to IgA+GL7+ cells.

Follicular dendritic cells (FDCs) are non-hematopoietic cells that are localized in the germinal centers (GCs) of lymph nodes (LNs) and are involved in humoral immunity. FDCs are a rare population that are sensitive to mechanical and chemical stimuli, making their isolation for analysis difficult. In Peyer's Patches, which are the main IgA-inductive sites, FDCs have been reported to be activated by retinoic acid receptor (RAR) and toll-like receptor (TLR) signals to induce IgA production. However, little is known about FDCs in mesenteric LNs (MLNs), although MLNs are also an IgA-inductive site. In this study, we efficiently isolated FDCs as CD35+ cells using anti-CD35 antibodies (Abs) and magnetic bead sorting. We found that CD35+ FDCs facilitated differentiation from B220+ B cells into IgA+GL7+ GC B-like cells but not IgA+CD138+ plasma cells. Furthermore, using CD35+ FDCs from LPS-resistant C3H/HeJ mice, the generation of IgA+GL7+ GC B-like cells was not altered significantly between wild-type and LPS-resistant mice. Moreover, the addition of RAR antagonists and agonists revealed that differentiation into IgA+GL7+ GC B-like cells required the activation of RAR, especially RAR-ß, in FDCs. The differentiation of IgA+GL7+ cells was promoted by FDCs in peripheral LNs as well as MLNs in our in vitro assay. Taken together, these results indicate that magnetic bead sorting with anti-CD35 Abs enable the efficient isolation of FDCs. Our data suggested that CD35+ FDCs can support differentiation of B cells into IgA+GL7+ GC B-like cells in environments that are not limited to MLNs, which can be stimulated by retinoic acid.