Initial 12 Cases of Robot-Assisted Gastrectomy for Gastric Cancer Using the Hinotori Surgical Robot System: Tips for the Efficient Introduction of a New Surgical Robot.

Introduction: The use of robotic platform for gastrectomy for gastric cancer is rapidly increasing. This study aimed to describe the perioperative outcomes of 12 patients who underwent robotic gastrectomy for gastric cancer using the hinotori™ surgical robot system (hinotori), a novel robot-assisted surgical platform, and compare the outcomes with the existing system, the da Vinci® Surgical System (DVSS). Methods: This study included 12 consecutive patients with gastric cancer who underwent robotic gastrectomy for gastric cancer using the hinotori between March 2023 and September 2023 at our institution. The comprehensive perioperative outcomes of these patients were retrospectively analyzed and compared to 11 patients who underwent robotic gastrectomy using the DVSS during the same period. Results: The median age and body mass index were 71 years (range: 56-86) and 22.7 kg/m2 (range: 16.1-26.7). Distal and total gastrectomy were performed in 8 and 4 patients, respectively. The median console time and operation times were 187 (range: 112-270) and 252 minutes (range: 173-339), respectively. The median blood loss was 3 mL (range: 2-5). No intra- or postoperative complications were observed. There were no significant differences in perioperative outcomes between the hinotori and the DVSS. Conclusions: Robotic gastrectomy for gastric cancer using the hinotori is a feasible procedure and achieved perioperative outcomes similar to that using the DVSS. Clinical Trial Registration number: 114167-1.

Clinical features of patients with pancreatic ductal adenocarcinoma with a history of other primary malignancies: A retrospective analysis.

Patients with pancreatic ductal adenocarcinoma (PDAC) that have a history of other primary malignancies are not well documented. The current study therefore aimed to evaluate the clinicopathological characteristics of patients with PDAC with or without a history of other primary malignancies. A total of 102 patients with surgically treated PDAC that presented with or without a history of other primary malignancies were retrospectively analyzed. A total of 25 patients (24.5%) had a history of other primary malignancies (age, with history of other primary malignancy vs. without, 74.2 vs. 68.9 years; P=0.005) and the reason for consultation (P<0.001) differed significantly between the groups with a history of other primary malignancies [HoM(+)] and without a history of other primary malignancies [HoM(-)]. Incidental indications during malignancy follow-up was the most common reason for the diagnosis of PDAC in the HoM(+) group. Conversely, there were no significant differences in the resectability (P=0.645), complete resection rate (P=0.774) and final stage (P=0.474) between the two groups. Disease-free survival was also not significantly different between the two groups (P=0.184). However, overall survival was significantly poorer in the HoM(+) group compared with the HoM(-) group (P=0.003). A history of other primary malignancies was also an independent predictor of poor overall survival (hazard ratio, 2.416; 95% confidence interval, 1.324-4.406; P=0.004). In conclusion, patients with PDAC and a history of other primary malignancies had significantly poorer overall survival than their counterparts, despite no differences in disease-free survival.

The Relationship between Bleeding and Contrast Extravasation Judged by Dual Energy CT after Acute Thrombectomy.

Objective: There are many cases in which computed tomography (CT) after acute thrombectomy demonstrates high-density areas, but it may be difficult to judge whether this is hemorrhage or contrast extravasation. Dual energy CT (DECT) is an imaging method that enables discrimination of substances by acquiring X-ray image data of two different energies. Methods: We performed DECT to distinguish hemorrhage from contrast extravasation in cases with high-density areas on CT after acute thrombectomy at our hospital, and we compared with T2*-weighted image on the following day. Results: Six patients comprising 22 areas had high-density areas on CT after acute thrombectomy. In all, 20 of the 22 high-density areas were determined to be contrast extravasation by DECT, and no cases of subsequent symptomatic cerebral hemorrhage were observed. However, 11 areas with new microbleeds were confirmed in the 20 extravasation areas on MRI-T2* images the day after thrombectomy. Conclusion: This examination suggested that the contrast extravasation and its concentration are involved in the presence of low-intensity areas on T2*.

A Case of Spontaneous Acute Subdural Hemorrhage Caused by a Dural Arteriovenous Fistula on the Convexity without Cortical Venous Reflux.

Bleeding from a dural arteriovenous fistula (DAVF) typically occurs in the form of an intracerebral or subarachnoid hemorrhage. Here, we report a rare case of a DAVF with an acute subdural hematoma (ASDH). A 29-year-old male presented to the emergency department with a complaint of progressing headache and nausea, with no reported episode of head trauma. Non-contrast CT revealed a left ASDH with a moderate midline shift. Digital subtraction angiography revealed a DAVF on the left parietal convexity. The DAVF was fed by the middle meningeal artery and drained into the superior sagittal sinus and the sphenoparietal sinus via the diploic vein without cortical venous reflux. The DAVF was treated with transarterial embolization using 25% diluted n-butyl cyanoacrylate prior to hematoma removal. The bleeding point was confirmed on the inner surface of the dura mater. The patient recovered well without any neurological deficits.

Reduced CBF recovery detected by longitudinal 3D-SSP SPECT analyses predicts outcome of postoperative patients after subarachnoid haemorrhage.

The aim of this study was to evaluate the impact of cerebral blood flow (CBF) recovery obtained from brain single-photon emission computed tomography (SPECT) images on postoperative outcome after aneurysmal subarachnoid haemorrhage (SAH). Twenty-nine patients who had undergone surgical clipping for ruptured anterior communicating artery aneurysms were analyzed prospectively. Routine measurements of CBF were performed using technetium-99 m hexamethyl propyleneamine oxine SPECT on days 4 and 14 after SAH. Regional voxel data analyzed by three dimensional stereotactic surface projection (3D-SSP) were compared between patients and age-matched normal database (NDB). In 3D-SSP analysis of all patients, cortical hypoperfusion around the surgical site in bilateral frontal lobes was evident on day 4 (P < .05 vs NDB), which was improved significantly on day 14. However, the recovery was less complete in patients with poor clinical grades (P < .05) and presenting symptoms attributable to delayed cerebral ischaemia (DCI) (P < .05) than those without. Multivariate analysis showed that patients with mild to moderate CBF recovery (relative Z-score differences of <4) (P = .014; odds ratio, 2.5; 95% confidence interval, 1.93-3.31) was independently associated with poor functional outcome at 3 months. We conclude that reduced CBF recovery detected by serial 3D-SSP SPECT image analyses can be a potential predictor of poor prognosis in postoperative patients after SAH.

Asymptomatic Mild Hyperperfusion for the Prediction of Clinical Outcome in Postoperative Patients After Subarachnoid Hemorrhage.

BACKGROUND Delayed cerebral ischemia (DCI) is one of the main causes of poor outcomes after subarachnoid hemorrhage (SAH). The early identification of DCI by noninvasive imaging modalities would provide valuable information of therapeutic intervention for improving the patient outcomes. We aimed to describe the clinical features of cerebral blood flow (CBF) data obtained from the single-photon emission computed tomography (SPECT) during the risk period for DCI after SAH. MATERIAL AND METHODS Clinical data from 94 SAH patients who underwent surgical clipping of anterior circulation aneurysms were reviewed retrospectively. 99mTc-HMPAO SPECT images were visually and semiquantitatively analyzed on days 7 and 14 after SAH. RESULTS In all cases, the areas of hypoperfusion were found in the middle cerebral artery territories. By contrast, the areas of mild hyperperfusion were always detected on the surgical side, the prevalence which increased from days 7 (n=28; 30%) to 14 (n=48; 51%) without neurological defects. Univariate analysis revealed that the hyperperfusion on day 14 had a significant relationship with functional outcome at 3 months (P=0.04). Multivariate analysis including age, clinical SAH grade, DCI, and hyperperfusion on day 14 showed that DCI (P=0.004; odds ratio [OR], 0.10; 95% confidence interval [CI], 0.02-0.48) and hyperperfusion on day 14 (P=0.002; OR, 2.44; 95% CI, 1.40-4.29) were independently associated with functional outcome at 3 months. CONCLUSIONS Delayed mild hyperperfusion around the surgical site can predict good prognosis after SAH, although it may hinder the CBF diagnosis of focal ischemia attributable to DCI.

Acupuncture Increases the Excitability of the Cortico-Spinal System in Patients with Chronic Disorders of Consciousness Following Traumatic Brain Injury.

OBJECTIVE: To evaluate the immediate effect of acupuncture on cortico spinal tract (CST) activity in patients with chronic disorders of consciousness (DOC) after traumatic brain injury (TBI) by measuring motor-evoked potential (MEP) using transcranial magnetic stimulation (TMS). DESIGN: Changes in several variables in the acupuncture session were compared with those in the control session without acupuncture in the same patients. SETTING: Chubu Medical Center for Prolonged Traumatic Brain Dysfunction, Gifu, Japan. PATIENTS: Fourteen patients (mean age ± standard deviation, 39 ± 17 years; 12 men) with chronic DOC (5 in a vegetative state and 9 in a minimally conscious state) following severe TBI. INTERVENTION: Acupuncture treatment was performed at GV 26, Ex-HN 3, bilateral LI 4, and ST 36 for 10 minutes. OUTCOME MEASURES: Main outcome measure was MEP amplitude. MEP amplitude, measured by using TMS on the primary motor cortex, was recorded from the abductor pollicis brevis muscle. MEP recordings were performed before acupuncture (baseline), 10 minutes after needle insertion (phase 1), and 10 minutes after needle removal (phase 2). As a control, the same procedure without acupuncture was performed on another day with the order randomized. MEP amplitude and latency were calculated. Evoked F-wave measurements were also performed to calculate maximum M-wave amplitude (Mmax), M-wave latency, and F-wave latency in the same muscle. Central motor conduction time (CMCT) and MEP/Mmax ratio were also calculated from the MEP and F-wave measurement data. RESULTS: MEP amplitude and MEP/Mmax were increased significantly in the acupuncture session at phases 1 and 2 compared with the control session (p < 0.001, p < 0.001, p < 0.001, and p = 0.001, respectively). CMCTs were reduced at phases 1 and 2 in the acupuncture session compared with the control session, and the change at phase 1 was statistically significant (P = 0.002). CONCLUSIONS: Acupuncture treatment increased the CST activity of patients with chronic DOC after severe TBI.

A novel approach for emerging and antibiotic resistant infections: Innate defense regulators as an agnostic therapy.

Innate Defense Regulators (IDRs) are short synthetic peptides that target the host innate immune system via an intracellular adaptor protein which functions at key signaling nodes. In this work, further details of the mechanism of action of IDRs have been discovered. The studies reported here show that the lead clinical IDR, SGX94, has broad-spectrum activity against Gram-negative and Gram-positive bacterial infections caused by intracellular or extracellular bacteria and also complements the actions of standard of care antibiotics. Based on in vivo and primary cell culture studies, this activity is shown to result from the primary action of SGX94 on tissue-resident cells and subsequent secondary signaling to activate myeloid-derived cells, resulting in enhanced bacterial clearance and increased survival. Data from non-clinical and clinical studies also show that SGX94 treatment modulates pro-inflammatory and anti-inflammatory cytokine levels, thereby mitigating the deleterious inflammatory consequences of innate immune activation. Since they act through host pathways to provide both broad-spectrum anti-infective capability as well as control of inflammation, IDRs are unlikely to be impacted by resistance mechanisms and offer potential clinical advantages in the fight against emerging and antibiotic resistant bacterial infections.

Oncostatin M regulates osteogenic differentiation of murine adipose-derived mesenchymal progenitor cells through a PKCdelta-dependent mechanism.

Oncostatin M (OSM) is an IL-6/LIF family cytokine that influences mesenchymal progenitor differentiation; however, the mechanisms of this activity have not been fully elucidated. Using uncommitted murine adipose tissue-derived mesenchymal progenitors, we have examined mechanisms of OSM-induced osteogenesis. Murine OSM (mOSM) induced osteogenic differentiation to a greater degree than interleukin (IL)-6 and other members of the gp130 cytokine family, promoting extracellular matrix mineralization as indicated by Alizarin Red S staining. mOSM also increased expression of osteogenesis-associated gene products BMP4, BMP7, Runx-2, and osteocalcin as assessed by immunoblotting and real-time quantitative PCR. Additionally, protein kinase C (PKC) delta activity was upregulated in response to OSM stimulation, and to a greater degree than IL-6. Knockdown of PKCdelta expression by use of RNA interference (RNAi) reduced OSM-mediated osteogenic differentiation and decreased expression of Runx-2. These findings suggest that OSM differentially promotes osteogenesis in non-committed mesenchymal progenitors relative to other gp130 cytokines. This activity correlates with selective activation of PKCdelta in OSM-treated cells, indicating that OSM-induced osteogenesis and upregulation of osteogenic gene products require activity of PKCdelta.

Comparison of support leg kinetics between side-step and cross-step cutting techniques.

The purpose of this study was to investigate differences in the support leg joint moment and moment power between side-step (SS) and cross-step (CS) cutting techniques with a prescribed 90 degrees cutting angle. Ground reaction forces (1,000Hz) and three-dimensional kinematics (250Hz) of SS and CS cutting techniques were collected from 20 male college athletes. Normalised peak knee extension moment was larger in the SS technique than in the CS technique (0.40 +/- 0.10 in SS; 0.26 +/- 0.08 in CS). In the SS technique, the knee extensors (-0.10 +/- 0.06 in SS; -0.02 +/- 0.04 in CS) and ankle plantarflexors (-0.12 +/- 0.05 in SS; -0.07 +/- 0.03 in CS) did significantly more negative work (normalised). The direction change angle (40.5 +/- 8.7 degrees in SS; 33.0 +/- 6.8 degrees in CS) and the decrease in horizontal velocity of the centre of mass (-0.63 +/- 0.23 m/s in SS; -0.31 +/- 0.23 m/s in CS) were significantly larger in the SS technique. These results suggest that the SS technique is an effective means of changing running direction at the expense of velocity of the centre of mass and that the CS technique is better for minimising the reduction in horizontal velocity of the centre of mass.

Brain activation by music in patients in a vegetative or minimally conscious state following diffuse brain injury.

OBJECTIVE: The aim of this study was to objectively evaluate the brain activity potential of patients with impaired consciousness in a chronic stage of diffuse brain injury (DBI) using functional MRI (fMRI) following music stimulation (MS). METHODS: Two patients in a minimally conscious state (MCS) and five patients in a vegetative state (VS) due to severe DBI were enrolled along with 21 healthy adults. This study examined the brain regions activated by music and assessed topographical differences of the MS-activated brain among healthy adults and these patients. RESULTS: MS was shown to activate the bilateral superior temporal gyri (STG) of both healthy adults and patients in an MCS. In four of five patients in a VS, however, no significant activation in STG could be induced by the same MS. The remaining patient in a VS displayed the same MS-induced brain activation in STG as healthy adults and patients in an MCS and this patient's status also improved to an MCS 4 months after the study. CONCLUSIONS: The presence of STG activation by MS may predict a possible improvement of patients in a VS to MCS and fMRI employing MS may be a useful modality to objectively evaluate consciousness in these patients.

Comparison of (11)C-methionine, (11)C-choline, and (18)F-fluorodeoxyglucose-PET for distinguishing glioma recurrence from radiation necrosis.

The aim of this study is to assess the different metabolic activities characteristic of glioma recurrence and radiation necrosis (RN) and to explore the diagnostic accuracy for differentiation of the two conditions using (11)C-methionine (MET), (11)C-choline (CHO), and (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET). Fifty patients with lesions suggestive of recurrent glioma by MRI underwent MET, CHO, and FDG-PET. All patients who had previously been treated with radiotherapy for malignant glioma were subjected to open surgery and pathological diagnosis (17 recurrent grade 3- gliomas (Gr.3s) comprising 7 anaplastic astrocytomas (AAs) and 10 anaplastic oligodendrogliomas (AOs), 17 recurrent glioblastomas (Gr.4s), and 16 RNs). We measured the PET/Gd volume ratio, the PET/Gd overlap ratio, and the lesion/normal brain uptake ratio (L/N ratio) and determined the optimal index of each PET scan. The PET/Gd volume ratio and the PET/Gd overlap ratio for RN were significantly lower than those of glioma recurrence only with MET-PET (P < 0.05). The L/N ratio of RN was significantly lower than that of Gr.4 with all PET imaging (P < 0.001) and was significantly lower than that of Gr.3, especially for AO, only with MET-PET images (P < 0.005). Receiver operating characteristic (ROC) analysis showed that the area under the curve of MET, CHO, and FDG was 92.5, 81.4, and 77.4, respectively. MET L/N ratio of greater than 2.51 provided the best sensitivity and specificity for establishing glioma recurrence (91.2% and 87.5%, respectively). These results demonstrated that MET-PET was superior to both CHO and FDG-PET for diagnostic accuracy in distinguishing glioma recurrence from RN.

Utility of fractional anisotropy imaging analyzed by statistical parametric mapping for detecting minute brain lesions in chronic-stage patients who had mild or moderate traumatic brain injury.

Diffusion tensor imaging (DTI) has recently evolved as valuable technique to investigate diffuse axonal injury (DAI). This study examined whether fractional anisotropy (FA) images analyzed by statistical parametric mapping (FA-SPM images) are superior to T(2)*-weighted gradient recalled echo (T2*GRE) images or fluid-attenuated inversion recovery (FLAIR) images for detecting minute lesions in traumatic brain injury (TBI) patients. DTI was performed in 25 patients with cognitive impairments in the chronic stage after mild or moderate TBI. The FA maps obtained from the DTI were individually compared with those from age-matched healthy control subjects using voxel-based analysis and FA-SPM images (p < 0.001). Abnormal low-intensity areas on T2*GRE images (T2* lesions) were found in 10 patients (40.0%), abnormal high-intensity areas on FLAIR images in 4 patients (16.0%), and areas with significantly decreased FA on FA-SPM image in 16 patients (64.0%). Nine of 10 patients with T2* lesions had FA-SPM lesions. FA-SPM lesions topographically included most T2* lesions in the white matter and the deep brain structures, but did not include T2* lesions in the cortex/near-cortex or lesions containing substantial hemosiderin regardless of location. All 4 patients with abnormal areas on FLAIR images had FA-SPM lesions. FA-SPM imaging is useful for detecting minute lesions because of DAI in the white matter and the deep brain structures, which may not be visualized on T2*GRE or FLAIR images, and may allow the detection of minute brain lesions in patients with post-traumatic cognitive impairment.

A speech expression disorder in patients with severe diffuse brain injury who emerged from a vegetative or minimally conscious state.

OBJECTIVE: The purpose of this study was to highlight a speech expression disorder considered as a mixed speech apraxia (SA) and dysarthria syndrome in patients with chronic severe diffuse brain injury (DBI) and to determine its correlation with anatomical localizations of brain lesions using neuroimaging. METHODS: Among 140 patients with chronic severe DBI, eight showed this type of speech disorder. MRI (five patients) and FDG-PET (six patients) procedures were performed. RESULTS: Affected patients could comprehend verbally, read words silently and express words using a word board. Compared with SA, the disorder is characterized by similarities in regards to reduced phonation and marked facio-oral apraxia, but by distinct differences in terms of an accompanying dysphagia and pyramidal/extra-pyramidal symptoms that are similar to symptoms associated with dysarthria due to pseudobulbar palsy. Diffuse regions of the white matter including the left arcuate fasciculus (AF) were significantly decreased in fractional anisotropy value. However, there was no significant cortical metabolic damage in FDG-PET. CONCLUSIONS: The observed speech disorder in these patients is a characteristic entity related to dysfunction of speech expression and may be attributable to damage of not only the AF but also a number of fibres that are related to dysarthria, cognitive and emotional impairments and pyramidal/extra-pyramidal symptoms.

Metabolic assessment of monofocal acute inflammatory demyelination using MR spectroscopy and (11)C-methionine-, (11)C-choline-, and (18)F-fluorodeoxyglucose-PET.

Monofocal acute inflammatory demyelination (MAID), which is observable by CT and MRI as a well-enhanced mass lesion with prominent perifocal edema, is very similar to malignant gliomas radiologically, making differential diagnosis of the two pathologies difficult. The aim of this study was to assess the different metabolic activities between MAID and malignant gliomas by MRS, methionine-PET, choline-PET, and FDG-PET. Six patients with MAID underwent methionine, choline, and FDG-PET, and 4 of the patients also underwent magnetic resonance spectroscopy (MRS). The images obtained from these patients were compared with the corresponding images of 19 anaplastic astrocytomas (AA) and 21 glioblastomas (GBM). The mean choline/creatine ratio of MAID was significantly lower than that of GBM. There were no significant differences in the mean NAA/creatine and lactate/creatine ratios among these pathologies. The methionine T/N ratio of MAID was significantly lower than those of AA and GBM. The choline T/N ratio of MAID was significantly lower than that of GBM. There were no significant differences in the FDG T/N ratios among these pathologies. These results demonstrate that the metabolic activity of MAID significantly differs in part from that of malignant gliomas. Combined PET and MRS neuroimaging examinations may be useful for differential diagnosis of these pathologies.

Sequestosome-1/p62 is the key intracellular target of innate defense regulator peptide.

Innate defense regulator-1 (IDR-1) is a synthetic peptide with no antimicrobial activity that enhances microbial infection control while suppressing inflammation. Previously, the effects of IDR-1 were postulated to impact several regulatory pathways including mitogen-activated protein kinase (MAPK) p38 and CCAAT-enhancer-binding protein, but how this was mediated was unknown. Using a combined stable isotope labeling by amino acids in cell culture-proteomics methodology, we identified the cytoplasmic scaffold protein p62 as the molecular target of IDR-1. Direct IDR-1 binding to p62 was confirmed by several biochemical binding experiments, and the p62 ZZ-type zinc finger domain was identified as the IDR-1 binding site. Co-immunoprecipitation analysis of p62 molecular complexes demonstrated that IDR-1 enhanced the tumor necrosis factor alpha-induced p62 receptor-interacting protein 1 (RIP1) complex formation but did not affect tumor necrosis factor alpha-induced p62-protein kinase zeta complex formation. In addition, IDR-1 induced p38 MAPK activity in a p62-dependent manner and increased CCAAT-enhancer-binding protein beta activity, whereas NF-kappaB activity was unaffected. Collectively, these results demonstrate that IDR-1 binding to p62 specifically affects protein-protein interactions and subsequent downstream events. Our results implicate p62 in the molecular mechanisms governing innate immunity and identify p62 as a potential therapeutic target in both infectious and inflammatory diseases.

Influence of the tissue microenvironment on Toll-like receptor expression by CD11c+ antigen-presenting cells isolated from mucosal tissues.

It is recognized that functional activities of antigen-presenting cells (APCs) in mucosal tissue sites differ from those of systemic APCs; however, it is unknown whether there are further differences between APC populations residing in different mucosal sites. In this study, we directly compared murine CD11c+ APCs isolated from colon, lung, and spleen and found that APCs isolated from these tissues differ considerably in Toll-like receptor (TLR) expression and responses to in vitro TLR ligand stimulation. We also provide evidence that tissue microenvironments dictate distinct patterns of TLR expression by CD11c+ APCs in different mucosal tissues. Moreover, CD11c+ cells isolated from different tissues have varied capacities to induce the development of T helper 1 (Th1), Th2, or regulatory CD4+ T cells. Thus, unique tissue microenvironments have a significant influence on determining TLR expression by CD11c+ cells that migrate to and reside in each mucosal tissue and are likely to modulate their functional activities.

[Case of infective endocarditis diagnosed with renal infarction].

A 46-year-old woman with sudden on set strong right flank pain was transferred to our hospital with the diagnosis of right renal infarction. Cardiac ultrasonography revealed a vegetation on the posterior cusp of the mitral valve, and the renal infarction was thought to be caused by renal artery embolism from infective endocarditis. Since the vegetation remained after antimicrobial therapy as conservative management, the patient was surgically treated by mitral annuloplasty. It has been known that infective endocarditis can cause renal infarction. Infective endocarditis requires immediate and adequate treatment because of high mortality. Therefore, the appropriate diagnosis of infective endocarditis is needed for patients with renal infarction without any other disorder causing renal infarction.

Mucosally delivered dendritic cells activate T cells independently of IL-12 and endogenous APCs.

In vitro manipulated dendritic cells (DC) have increasingly been used as a promising vaccine formulation against cancer and infectious disease. However, improved understanding of the immune mechanisms is needed for the development of safe and efficacious mucosal DC immunization. We have developed a murine model of respiratory mucosal immunization by using a genetically manipulated DC vaccine. Within 24 h of intranasal delivery, the majority of vaccine DCs migrated to the lung mucosa and draining lymph nodes and elicited a significant level of T cells capable of IFN-gamma secretion and CTL in the airway lumen as well as substantial T cell responses in the spleen. And such T cell responses were associated with enhanced protection against respiratory mucosal intracellular bacterial challenge. In comparison, parenteral i.m. DC immunization did not elicit marked airway luminal T cell responses and immune protection regardless of strong systemic T cell activation. Although repeated mucosal DC delivery boosted Ag-specific T cells in the airway lumen, added benefits to CD8 T cell activation and immune protection were not observed. By using MHC-deficient vaccine DCs, we further demonstrated that mucosal DC immunization-mediated CD8 and CD4 T cell activation does not require endogenous DCs. By using IL-12-deficient vaccine DCs, we also observed that IL-12(-/-) DCs failed to migrate to the lymph nodes but remained capable of T cell activation. Our observations indicate that mucosal delivery of vaccine DCs represents an effective approach to enhance mucosal T cell immunity, which may operate independent of vaccine IL-12 and endogenous DCs.

Critical negative regulation of type 1 T cell immunity and immunopathology by signaling adaptor DAP12 during intracellular infection.

Transmembrane signaling adaptor DAP12 has increasingly been recognized for its important role in innate responses. However, its role in the regulation of antimicrobial T cell responses has remained unknown. In our current study, we have examined host defense, T cell responses, and tissue immunopathology in models of intracellular infection established in wild-type and DAP12-deficient mice. During mycobacterial infection, lack of DAP12 leads to pronounced proinflammatory and Th1 cytokine responses, overactivation of Ag-specific CD4 and CD8 T cells of type 1 phenotype, and heightened immunopathology both in the lung and lymphoid organs. DAP12-deficient airway APC display enhanced NF-kappaB activation and cytokine responses upon TLR stimulation or mycobacterial infection in vitro. Of importance, adoptive transfer of Ag-loaded DAP12-deficient APC alone could lead to overactivation of transferred transgenic or endogenous wild-type T cells in vivo. We have further found that the immune regulatory role by DAP12 is not restricted only to intracellular bacterial infection, since lack of this molecule also leads to uncontrolled type 1 T cell activation and severe immunopathology and tissue injury during intracellular viral infection. Our study thus identifies DAP12 as an important novel immune regulatory molecule that acts, via APC, to control the level of antimicrobial type 1 T cell activation and immunopathology.