Traumatic Brain Injury Alters Dendritic Cell Differentiation and Distribution in Lymphoid and Non-Lymphoid Organs

Pathophysiological consequences of traumatic brain injury (TBI) mediated secondary injury remain incompletely understood. In particular, the impact of TBI on the differentiation and maintenance of dendritic cells (DCs), remains completely unknown. Here, we report that DC- differentiation, maintenance and functions are altered at both early and late phases of TBI. Our studies identify that; 1. frequencies and absolute numbers of DCs in the spleen and BM are altered at both acute and late phases of TBI; 2. surface expression of key molecules involved in antigen presentation of DCs were affected both at early and late phases of TBI; 3. distribution and functions of tissue-specific DC subsets of both circulatory and lymphatic systems were imbalanced following TBI; 4. early differentiation program of DCs, especially the commitment of hematopoietic stem cells to common DC progenitors, were deregulated after TBI; and 5. intracellular ROS levels were reduced in DC progenitors and differentiated DCs at both early and late phases of TBI. Our data demonstrate, for the first time, that TBI affects the distribution pattern of DCs and induces an imbalance among DC subsets in both lymphoid and non-lymphoid organs. In addition, the current study demonstrates that TBI results in reduced levels of ROS in DCs at both early and late phases of TBI, which may explain altered DC differentiation paradigm following TBI. A deeper understanding on the molecular mechanisms that contribute to DC defects following TBI would be essential and beneficial in treating infections in patients with acute central nervous system (CNS) injuries.

Traumatic brain injury alters dendritic cell differentiation and distribution in lymphoid and non-lymphoid organs

Pathophysiological consequences of traumatic brain injury (TBI) mediated secondary injury remain incompletely understood. In particular, the impact of TBI on the differentiation and maintenance of dendritic cells (DCs), remains completely unknown. Here, we report that DC- differentiation, maintenance and functions are altered at both early and late phases of TBI. Our studies identify that; 1. frequencies and absolute numbers of DCs in the spleen and BM are altered at both acute and late phases of TBI; 2. surface expression of key molecules involved in antigen presentation of DCs were affected both at early and late phases of TBI; 3. distribution and functions of tissue-specific DC subsets of both circulatory and lymphatic systems were imbalanced following TBI; 4. early differentiation program of DCs, especially the commitment of hematopoietic stem cells to common DC progenitors, were deregulated after TBI; and 5. intracellular ROS levels were reduced in DC progenitors and differentiated DCs at both early and late phases of TBI. Our data demonstrate, for the first time, that TBI affects the distribution pattern of DCs and induces an imbalance among DC subsets in both lymphoid and non-lymphoid organs. In addition, the current study demonstrates that TBI results in reduced levels of ROS in DCs at both early and late phases of TBI, which may explain altered DC differentiation paradigm following TBI. A deeper understanding on the molecular mechanisms that contribute to DC defects following TBI would be essential and beneficial in treating infections in patients with acute central nervous system (CNS) injuries.

Traumatic Brain Injury Alters Dendritic Cell Differentiation And Distribution In Lymphoid And Non-Lymphoid Organs

Pathophysiological consequences of traumatic brain injury (TBI) mediated secondary injury remain incompletely understood. In particular, the impact of TBI on the differentiation and maintenance of dendritic cells (DCs), remains completely unknown. Here, we report that DC- differentiation, maintenance and functions are altered at both early and late phases of TBI. Our studies identify that; 1. frequencies and absolute numbers of DCs in the spleen and BM are altered at both acute and late phases of TBI; 2. surface expression of key molecules involved in antigen presentation of DCs were affected both at early and late phases of TBI; 3. distribution and functions of tissue-specific DC subsets of both circulatory and lymphatic systems were imbalanced following TBI; 4. early differentiation program of DCs, especially the commitment of hematopoietic stem cells to common DC progenitors, were deregulated after TBI; and 5. intracellular ROS levels were reduced in DC progenitors and differentiated DCs at both early and late phases of TBI. Our data demonstrate, for the first time, that TBI affects the distribution pattern of DCs and induces an imbalance among DC subsets in both lymphoid and non-lymphoid organs. In addition, the current study demonstrates that TBI results in reduced levels of ROS in DCs at both early and late phases of TBI, which may explain altered DC differentiation paradigm following TBI. A deeper understanding on the molecular mechanisms that contribute to DC defects following TBI would be essential and beneficial in treating infections in patients with acute central nervous system (CNS) injuries.

Harnessing iNKT cells to improve in situ vaccination for cancer therapy

<p>Toll-like receptor (TLR) agonism in combination with the activation of type I NKT (iNKT) cells through systemic administration of their respective agonists has been shown to have a cooperative effect on activating antigen-presenting cells, stimulating cytokine production, and inducing adaptive immune responses to co-administered antigens. Here, it was hypothesised that it might be possible to harness these activities to treat solid tumours locally via intratumoural treatment to combat tumour growth while reducing toxicity to other organs. An intratumoural treatment model combining the stimulatory activity of unmethylated DNA oligonucleotides consisting of synthetic cytosine-guanine motifs (CpG), a TLR9 agonist, with activation of iNKT cells through administration of the CD1d-binding iNKT agonist α-galactosylceramide (α-GalCer) intratumourally was shown to have significant anti-tumour activity. The treatment regimen showed superior efficacy to that achieved with either agent alone in several in vivo models representing different types of cancer. In some models, the combination of α-GalCer and CpG was effective at inducing the complete rejection of both treated and untreated tumours through the induction of a systemic adaptive immune response. Post tumour rejection, a memory response protected against rechallenge with the same, or similar, tumours. Intratumoural administration of the agents was associated with increases in IFN-α in the tumour (rather than the serum), and blockade or removal of the IFN-α receptor abrogated the anti-tumour response. The importance of the draining lymph node and spleen in anti-tumour activity (as shown by the excision of these organs), and liver enzyme responses, suggested that some of the agonists/antigens may have dispersed into the lymphoid organs and liver to support the response. Nonetheless, the anti-tumour effect was dependent on local effects of the intratumoural administration on the tumour microenvironment, as subcutaneous and peritumoural routes of administration only minimally affected tumour growth despite the reagents potentially having greater exposure to lymphoid organs. Through the use of various techniques including knockout mice, neutralising monoclonal antibodies, confocal microscopy and flow cytometry, it was shown that the combination of α-GalCer and CpG was dependent on the effector activity of CD8+ cells. However, optimal activity was associated with changes in other immune cell types, notably recruitment of iNKT cells into the tumour bed, and was also associated with induction of serum antibodies that could transfer some protection to naïve hosts. Induction of a successful response was dependent on conventional dendritic cells (DCs) of the “cDC1” phenotype, which are known to be effective at antigen cross-presentation to CD8+ T cells, while full tumour rejection also required the activity of plasmacytoid DCs, which are significant producers of IFN-α. In less immunogenic tumour models, the addition of relevant tumour associated antigens (TAAs) improved the anti-tumour response. The TAAs could be added as part of an admix, but improved responses were obtained when TAAs were chemically conjugated to α-GalCer via an enzymatically cleavable linker. Alternatively, intratumoural administration of α-GalCer and CpG as free agents could be combined effectively with low dose systemic chemotherapy to induce curative responses, potentially through a mechanism involving immunogenic cell death to improve the immunogenicity of TAAs in situ.</p>

Morphometric Study of Cadaveric Spleen in Vidarbha Region

Background: Spleen is one of the largest lymphoid organs that are involved in haemopoitic function also during fetal life. Its anatomy is useful not only for Anatomist but also for Surgeons, Radiologists and Physicians. A lot of variations are observed in the spleen from its shape to size which is important to diagnose or treat the number of diseases. Methodology: This study was carried out on 60 spleens in the dissection hall of our medical college which were removed during routine undergraduate dissection. The parameters studies were shape of the spleen, number of notches (single or multiple), location of notches (Superior or inferior border), weight, breadth, width or length. Results: The 90% spleens has single notch. The weight of the spleens ranges from 89 gm to 220 gm with an average 142.6 gm. Range of breadth observed 3.5cm to7.4cm with an average 5.8cm, Range of width observed 2.8cm to 5.7cm with an average 4.1cm. Range of length observed 8.1cm to13.2cm with an average 11.7cm. Conclusion: Morphological variation is very common in spleen and varies according to the genetic, geographic, nutrition and work habits of individual and varies regions to regions of India. Morphological analysis is under reported and need to be carry out at different regions and places for obtaining more accurate data.

Harnessing iNKT cells to improve in situ vaccination for cancer therapy

<p>Toll-like receptor (TLR) agonism in combination with the activation of type I NKT (iNKT) cells through systemic administration of their respective agonists has been shown to have a cooperative effect on activating antigen-presenting cells, stimulating cytokine production, and inducing adaptive immune responses to co-administered antigens. Here, it was hypothesised that it might be possible to harness these activities to treat solid tumours locally via intratumoural treatment to combat tumour growth while reducing toxicity to other organs. An intratumoural treatment model combining the stimulatory activity of unmethylated DNA oligonucleotides consisting of synthetic cytosine-guanine motifs (CpG), a TLR9 agonist, with activation of iNKT cells through administration of the CD1d-binding iNKT agonist α-galactosylceramide (α-GalCer) intratumourally was shown to have significant anti-tumour activity. The treatment regimen showed superior efficacy to that achieved with either agent alone in several in vivo models representing different types of cancer. In some models, the combination of α-GalCer and CpG was effective at inducing the complete rejection of both treated and untreated tumours through the induction of a systemic adaptive immune response. Post tumour rejection, a memory response protected against rechallenge with the same, or similar, tumours. Intratumoural administration of the agents was associated with increases in IFN-α in the tumour (rather than the serum), and blockade or removal of the IFN-α receptor abrogated the anti-tumour response. The importance of the draining lymph node and spleen in anti-tumour activity (as shown by the excision of these organs), and liver enzyme responses, suggested that some of the agonists/antigens may have dispersed into the lymphoid organs and liver to support the response. Nonetheless, the anti-tumour effect was dependent on local effects of the intratumoural administration on the tumour microenvironment, as subcutaneous and peritumoural routes of administration only minimally affected tumour growth despite the reagents potentially having greater exposure to lymphoid organs. Through the use of various techniques including knockout mice, neutralising monoclonal antibodies, confocal microscopy and flow cytometry, it was shown that the combination of α-GalCer and CpG was dependent on the effector activity of CD8+ cells. However, optimal activity was associated with changes in other immune cell types, notably recruitment of iNKT cells into the tumour bed, and was also associated with induction of serum antibodies that could transfer some protection to naïve hosts. Induction of a successful response was dependent on conventional dendritic cells (DCs) of the “cDC1” phenotype, which are known to be effective at antigen cross-presentation to CD8+ T cells, while full tumour rejection also required the activity of plasmacytoid DCs, which are significant producers of IFN-α. In less immunogenic tumour models, the addition of relevant tumour associated antigens (TAAs) improved the anti-tumour response. The TAAs could be added as part of an admix, but improved responses were obtained when TAAs were chemically conjugated to α-GalCer via an enzymatically cleavable linker. Alternatively, intratumoural administration of α-GalCer and CpG as free agents could be combined effectively with low dose systemic chemotherapy to induce curative responses, potentially through a mechanism involving immunogenic cell death to improve the immunogenicity of TAAs in situ.</p>

Glucocorticoid production in lymphoid organs: Acute effects of lipopolysaccharide in neonatal and adult mice

Glucocorticoids (GCs) are critical modulators of the immune system. The hypothalamic-pituitary-adrenal (HPA) axis regulates circulating GC levels and is stimulated by endotoxins. Lymphoid organs also produce GCs; however, it is not known how lymphoid GC levels are regulated in response to endotoxins. We assessed whether an acute challenge of lipopolysaccharide (LPS) increases lymphoid levels of GCs, steroidogenic enzymes expression, and components of the HPA axis (e.g., CRH) expression. We administered LPS (50µg/kg i.p.) or vehicle control to male and female C57BL/6J neonatal (post-natal day (PND) 5) and adult (PND90) mice and collected blood, bone marrow, thymus, and spleen 4 hr later. We measured progesterone, 11-deoxycorticosterone (DOC), corticosterone, and 11-dehydrocorticosterone (DHC) via liquid chromatography tandem mass spectrometry (LC-MS/MS). We measured gene expression of key steroidogenic enzymes (Cyp11b1, Hsd11b1, and Hsd11b2) and HPA axis components (Crh, Crhr1, Pomc, and Mc2r) via qPCR. At PND5, LPS induced greater increases in steroid levels in lymphoid organs than in blood. In contrast, at PND90, LPS induced greater increases in steroid levels in blood than in lymphoid organs. Steroidogenic enzyme transcripts were present in all lymphoid organs, and LPS altered steroidogenic enzyme expression predominately in the spleen. Lastly, we detected transcripts of key HPA axis components in all lymphoid organs, and there was an effect of LPS in the spleen. Taken together, these data suggest that LPS regulates GC production by lymphoid organs, similar to its effects on the adrenal glands, and the effects of LPS might be mediated by local expression of CRH and ACTH.

Tonsil-Derived Mesenchymal Stem Cells Inhibit the Proliferation of Hematological Cancer Cells through Downregulation of IL-6 Gene Expression under Hyperthermia

Stem cells are extensively being studied as promising biological therapeutic candidates in cancer treatment. In various cancer types, some studies show proliferative effects while others show inhibitory effects of MSCs on tumors. Some studies have reported that MSCs isolated from different sources display different anti-cancer properties. Tonsils are one of the secondary lymphoid organs that form an important part of the immune system and located at the mucosal interface. The relation between secondary lymphoid organs and cancer progression lead us to investigate the effect of tonsil-derived MSCs (T-MSC) on cancer treatment. Therefore, we aimed to determine the anti-tumoral effects of tonsil-derived MSCs cultured at febrile temperature on hematological cancer cell lines. We found that co-culture of K562 cells and MOLT-4 with T-MSCs significantly decreased the viable cell number post 7 days of the culture under the febrile and normal culture conditions. Besides, the T-MSC co-culture not only induced the apoptosis on K562 and MOLT-4 cells but also, induced the cell cycle arrest at G2-M phase on MOLT-4 cells. The apoptotic effect of T-MSC co-culture under febrile stimulation was confirmed by upregulation of Bax, c-myc genes for K562 cells and upregulation of Bax, p53 and c-myc genes for MOLT-4 cells in transcriptional level. Our study has contributed to highlight the effect of the cellular interaction between the T-MSCs and human hematological cancer cells during in vitro co-culture under hyperthermia for tumor progression. In the light of these results, we indicated that tonsil-derived MSCs have promising therapeutic potential for cancer therapy.

Tonsillectomy, appendectomy and splenectomy: sequels and malignant evolution

The excision of secondary lymphoid organs might not be harmless. Although the procedure itself, is less and less performed presently, infectious sequels in total splenectomy might occur and are possibly fatal. Among further complications, thromboembolic and immune alterations should also be expected. The most debatable of consequences, probably associated with an immune adjustment, concerns the development of malignancies. Considering post-splenectomy tumors, discrepancies emerge between their occurrence in humans, and their consequent protective effect in experimental animals. It is recommended that surgeons aspire at preserving as much of lymphoid tissues a feasible, when performing such resections.

Delivery of nanovaccine towards lymphoid organs: recent strategies in enhancing cancer immunotherapy

With the in-depth exploration on cancer therapeutic nanovaccines, increasing evidence shows that the poor delivery of nanovaccines to lymphoid organs has become the culprit limiting the rapid induction of anti-tumor immune response. Unlike the conventional prophylactic vaccines that mainly form a depot at the injection site to gradually trigger durable immune response, the rapid proliferation of tumors requires an efficient delivery of nanovaccines to lymphoid organs for rapid induction of anti-tumor immunity. Optimization of the physicochemical properties of nanovaccine (e.g., size, shape, charge, colloidal stability and surface ligands) is an effective strategy to enhance their accumulation in lymphoid organs, and nanovaccines with dynamic structures are also designed for precise targeted delivery of lymphoid organs or their subregions. The recent progress of these nanovaccine delivery strategies is highlighted in this review, and the challenges and future direction are also discussed. Graphical Abstract