Double Transgenic Mouse Model Research Articles

A new target for Alzheimer’s disease: A small molecule SERCA activator is neuroprotective in vitro and improves memory and cognition in APP/PS1 mice

Amongst the cellular cacophony of altered signals in Alzheimer’s disease (AD), disrupted Ca2+ homeostasis and consequential endoplasmic reticulum (ER) stress signals have been recognized as key determinants of neuron fate. This altered Ca2+ state is accompanied by a failing sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump, which has been recognized as a causal feature of the underlying disease state. Repair of the Ca2+ dyshomeostasis represents a putative drug target via alleviation of ER stress and rescue of injured neurons, effectively modifying the AD state. Herein, we report a small molecule SERCA activator that rescues brain cells and raises ER Ca2+ in vitro, and shows efficacy in the APP/PS1 double transgenic mouse model of Alzheimer’s disease. These results support SERCA activation as a therapeutic target for AD.

Endoplasmic reticulum stress responses in mouse models of Alzheimer's disease: Overexpression paradigm versus knockin paradigm

Endoplasmic reticulum (ER) stress is believed to play an important role in the etiology of Alzheimer's disease (AD). The accumulation of misfolded proteins and perturbation of intracellular calcium homeostasis are thought to underlie the induction of ER stress, resulting in neuronal dysfunction and cell death. Several reports have shown an increased ER stress response in amyloid precursor protein (APP) and presenilin1 (PS1) double-transgenic (Tg) AD mouse models. However, whether the ER stress observed in these mouse models is actually caused by AD pathology remains unclear. APP and PS1 contain one and nine transmembrane domains, respectively, for which it has been postulated that overexpressed membrane proteins can become wedged in a misfolded configuration in ER membranes, thereby inducing nonspecific ER stress. Here, we used an App-knockin (KI) AD mouse model that accumulates amyloid-β (Aβ) peptide without overexpressing APP to investigate whether the ER stress response is heightened because of Aβ pathology. Thorough examinations indicated that no ER stress responses arose in App-KI or single APP-Tg mice. These results suggest that PS1 overexpression or mutation induced a nonspecific ER stress response that was independent of Aβ pathology in the double-Tg mice. Moreover, we observed no ER stress in a mouse model of tauopathy (P301S-Tau-Tg mice) at various ages, suggesting that ER stress is also not essential in tau pathology-induced neurodegeneration. We conclude that the role of ER stress in AD pathogenesis needs to be carefully addressed in future studies.

The NLRP3 Inflammasome May Contribute to Pathologic Neovascularization in the Advanced Stages of Diabetic Retinopathy

Diabetic retinopathy (DR) is a retinal microvascular disease characterized by inflammatory and angiogenic pathways. In this study, we evaluated NLRP3 inflammasome in a double transgenic mouse model, Akimba (Ins2AkitaxVEGF+/−), which demonstrates hyperglycemia, vascular hyperpermeability and neovascularization seen in the proliferative DR. Retinal structural integrity, vascular leakage and function were examined by fundus photography, fluorescein angiography, optical coherence tomography, retinal flat mounts, laser speckle flowgraphy (LSFG), and electroretinography in Akimba and its parental strains, Akita (Ins2Akita) and Kimba (trVEGF029) mice. Inflammatory mechanisms involving NLRP3 inflammasome were investigated using real time-PCR, immunohistochemistry, ELISA and western blots. We observed an increased vascular leakage, reduced retinal thickness, and function in Akimba retina. Also, Akimba retina depicts decreased relative flow volume measured by LSFG. Most importantly, high levels of IL-1β along with increased NLRP3, ASC, and Caspase-1 at mRNA and protein levels were observed in Akimba retina. However, the in vivo functional role remains undefined. In conclusion, increased activation of macroglia (GFAP), microglia (Iba-1 and OX-42) and perivascular macrophages (F4/80 and CD14) together with pro-inflammatory (IL-1β and IL-6) and pro-angiogenic markers (PECAM-1, ICAM-1, VEGF, Flt-1, and Flk-1), suggested a critical role for NLRP3 inflammasome in the Akimba mouse model depicting advanced stages of DR pathogenesis.

Protective effects of long-term lithium administration in a slowly progressive SMA mouse model.

In the present study we evaluated the long-term effects of lithium administration to a knock-out double transgenic mouse model (Smn-/-; SMN1A2G+/-; SMN2+/+) of Spinal Muscle Atrophy type III (SMA-III). This model is characterized by very low levels of the survival motor neuron protein, slow disease progression and motor neuron loss, which enables to detect disease-modifying effects at delayed time intervals. Lithium administration attenuates the decrease in motor activity and provides full protection from motor neuron loss occurring in SMA-III mice, throughout the disease course. In addition, lithium prevents motor neuron enlargement and motor neuron heterotopy and suppresses the occurrence of radial-like glial fibrillary acidic protein immunostaining in the ventral white matter of SMA-III mice. In SMA-III mice long-term lithium administration determines a dramatic increase of survival motor neuron protein levels in the spinal cord. These data demonstrate that long-term lithium administration during a long-lasting motor neuron disorder attenuates behavioural deficit and neuropathology. Since low level of survival motor neuron protein is bound to disease severity in SMA, the robust increase in protein level produced by lithium provides solid evidence which calls for further investigations considering lithium in the long-term treatment of spinal muscle atrophy.

An exploratory investigation of brain-selective estrogen treatment in males using a mouse model of Alzheimer's disease

Estrogens are neuroprotective, and studies suggest that they may mitigate the pathology and symptoms of Alzheimer's disease (AD) in female models. However, central estrogen effects have not been examined in males in the context of AD. The purpose of this follow-up study was to assess the benefits of a brain-selective 17β-estradiol estrogen prodrug, 10β,17β-hydroxyestra-1,4-dien-3-one (DHED), also in the male APPswe/PS1dE9 double-transgenic mouse model of the disease. After continuously exposing 6-month old animals to DHED for two months, their brains showed decreased amyloid precursor and amyloid-β protein levels. The DHED-treated APPswe/PS1dE9 double transgenic subjects also exhibited enhanced performance in a cognitive task, while 17β-estradiol treatment did not reach statistical significance. Taken together, data presented here suggest that DHED may also have therapeutic benefit in males and warrant further investigations to fully elucidate the potential of targeted estrogen therapy for a gender-independent treatment of early-stage AD.

Atrial ERK1/2 activation in the embryo leads to incomplete Septal closure: a novel mouse model of atrial Septal defect

BackgroundMEK1 mutation and activated MAPK signaling has been found in patients with RASopathies and abnormal cardiac development. Previous studies have suggested that regulation of fetal MAPK signaling is essential for normal cardiac development. We investigated the effect of active MEK1 overexpression on fetal atrial septal development.Methods and resultsAn inducible double transgenic (DTg) mouse model was developed in which cardiac-specific fetal expression of a constitutively active form of human MEK1 (aMEK1) was induced primarily in the atrium via the withdrawal of doxycycline from the drinking water of pregnant mice. Atrial septal defect (ASD) was found in 51% (23/45) of DTg mice. Fifty-two percent (12/23) of ASD mice died before weaning, and surviving ASD mice exhibited hypertrophic hearts with enlarged right atria and decreased fractional shorting (40 ± 2% vs. 48 ± 0%, p < 0.05). The model mimicked human ASD in several key clinical features: severe ASD was associated with growth impairment; ASD-specific mortality was highest within the early postnatal period; despite an even distribution of ASD among the sexes, early mortality was significantly higher in males. The expression of aMEK1 and increased phosphorylation of ERK1/2 was documented via Western blot in DTg fetal hearts, with the largest increases seen in atrial tissue. In an alternative transgenic aMEK1 model with elevated atrial MKP3 expression and corresponding suppression of increases in ERK1/2 phosphorylation, animals did not develop ASD.ConclusionThis new model of ASD suggests that enhanced atrial MEK1-ERK1/2 signaling during fetal development disrupts normal atrial septation, possibly regulated by the balance of ERK1/2 phosphorylation.

Andrographolide sulfonate improves Alzheimer-associated phenotypes and mitochondrial dysfunction in APP/PS1 transgenic mice

Alzheimer’s disease is a neurodegenerative disorder with Amyloid-β plaques onset, synaptic damage, and cognitive decline. Aβ deposits cause pathological events including oxidative stress, mitochondrial dysfunction, and neuron death. In this study, APPswe/PSENΔ9 double transgenic mice model was used to imitate Alzheimer’s disease and the effect and possible mechanism of Andrographolide sulfonate were examined. Andrographolide sulfonate was given to the mice for 7 months before the onset of Aβ plaque. Spatial memory test showed that Andrographolide sulfonate treatment prevented cognitive decline. Aβ deposits were not affected while hippocampus and synapse damage was significantly alleviated. Mechanism studies showed that oxidative stress and mitochondrial swelling was reduced after Andrographolide sulfonate administration. These findings suggest that Andrographolide sulfonate, which has been applied in clinical medicine, might be a promising therapeutic agent for AD therapy via mitochondria protection.

Intravital longitudinal wide-area imaging of dynamic bone marrow engraftment and multilineage differentiation through nuclear-cytoplasmic labeling.

Bone marrow is a vital tissue that produces the majority of erythrocytes, thrombocytes, and immune cells. Bone marrow transplantation (BMT) has been widely performed in patients with blood disorders and cancers. However, the cellular-level behaviors of the transplanted bone marrow cells over wide-areas of the host bone marrow after the BMT are not fully understood yet. In this work, we performed a longitudinal wide-area cellular-level observation of the calvarial bone marrow after the BMT in vivo. Using a H2B-GFP/β-actin-DsRed double-transgenic mouse model as a donor, a subcellular-level nuclear-cytoplasmic visualization of the transplanted bone marrow cells was achieved, which enabled a direct in vivo dynamic monitoring of the distribution and proliferation of the transplanted bone marrow cells. The same spots in the wide-area of the calvarial bone marrow were repeatedly identified using fluorescently labeled vasculature as a distinct landmark. It revealed various dynamic cellular-level behaviors of the transplanted BM cells in early stage such as cluster formation, migration, and active proliferation in vivo.

Developmental and reproductive toxicity testing of a therapeutic monoclonal antibody in a double-transgenic mouse model of Alzheimer's disease

Developmental and reproductive toxicity testing of a therapeutic monoclonal antibody in a double-transgenic mouse model of Alzheimer's disease

Amyloid-β and islet amyloid pathologies link Alzheimer's disease and type 2 diabetes in a transgenic model.

Alzheimer's disease (AD) and type 2 diabetes (T2D) present a significant risk to each other. AD and T2D are characterized by deposition of cerebral amyloid-β (Aβ) and pancreatic human islet amyloid polypeptide (hIAPP), respectively. We investigated the role of amyloidogenic proteins in the interplay between these diseases. A novel double transgenic mouse model combining T2D and AD was generated and characterized. AD-related amyloid transgenic mice coexpressing hIAPP displayed peripheral insulin resistance, hyperglycemia, and glucose intolerance. Aβ and IAPP amyloid co-deposition increased tau phosphorylation, and a reduction in pancreatic β-cell mass was detected in islets. Increased brain Aβ deposition and tau phosphorylation and reduced insulin levels and signaling were accompanied by extensive synaptic loss and decreased neuronal counts. Aβ immunization rescued the peripheral insulin resistance and hyperglycemia, suggesting a role for Aβ in T2D pathogenesis for individuals predisposed to AD. These findings demonstrate that Aβ and IAPP are key factors in the overlapping pathologies of AD and T2D.-Wijesekara, N., Ahrens, R., Sabale, M., Wu, L., Ha, K., Verdile, G., Fraser, P. E. Amyloid-β and islet amyloid pathologies link Alzheimer's disease and type 2 diabetes in a transgenic model.

Reproductive and developmental toxicology studies with gantenerumab in PS2APP transgenic mice

Gantenerumab is intended for the treatment of Alzheimer’s disease. It is a fully human recombinant monoclonal IgG1 which binds aggregated forms of amyloid beta such as Aβ oligomers, fibrils and neuritic amyloid plaques. A full package of developmental and reproductive toxicity (DART) studies was performed in the PS2APP double-transgenic mouse model of Alzheimer’s disease. A combined fertility and embryo fetal development study and a pre-and post-natal development study were performed. The PS2APP mouse model allowed a more complete DART evaluation than would have been possible in conventional species or strains which do not express the target antigen of gantenerumab. No developmental or reproductive hazards were identified.

INT131 increases dendritic arborization and protects against Aβ toxicity by inducing mitochondrial changes in hippocampal neurons

In previous studies, we have demonstrated the beneficial effects of classic PPARγ agonists on neuroprotection against Aβ oligomer neurotoxicity in a double transgenic mouse model of Alzheimer' disease (AD). INT-131, a novel, non-thiazolidinedione compound that belongs to a new family of drugs, selective PPARγ modulators (SPPARMs), has provided an emerging opportunity for the treatment of type 2 diabetes mellitus and metabolic syndrome. However, its role in the central nervous system has not been studied. The aim of this study was to evaluate the putative neuroprotective role of INT131 in hippocampal neurons. We found that INT131 increased dendritic branching, promoted neuronal survival against Aβ amyloid, increased expression of PGC1-1α and modulated neuronal mitochondrial dynamics. Our results suggest that INT131, a drug that has been shown to be safe and effective in metabolic disorders, may constitute a new therapeutic alternative for AD.

CD1b-autoreactive T cells contribute to hyperlipidemia-induced skin inflammation in mice.

A large proportion of human T cells are autoreactive to group 1 CD1 proteins, which include CD1a, CD1b, and CD1c. However, the physiological role of the CD1 proteins remains poorly defined. Here, we have generated a double-transgenic mouse model that expresses human CD1b and CD1c molecules (hCD1Tg) as well as a CD1b-autoreactive TCR (HJ1Tg) in the ApoE-deficient background (hCD1Tg HJ1Tg Apoe-/- mice) to determine the role of CD1-autoreactive T cells in hyperlipidemia-associated inflammatory diseases. We found that hCD1Tg HJ1Tg Apoe-/- mice spontaneously developed psoriasiform skin inflammation characterized by T cell and neutrophil infiltration and a Th17-biased cytokine response. Anti-IL-17A treatment ameliorated skin inflammation in vivo. Additionally, phospholipids and cholesterol preferentially accumulated in diseased skin and these autoantigens directly activated CD1b-autoreactive HJ1 T cells. Furthermore, hyperlipidemic serum enhanced IL-6 secretion by CD1b+ DCs and increased IL-17A production by HJ1 T cells. In psoriatic patients, the frequency of CD1b-autoreactive T cells was increased compared with that in healthy controls. Thus, this study has demonstrated the pathogenic role of CD1b-autoreactive T cells under hyperlipidemic conditions in a mouse model of spontaneous skin inflammation. As a large proportion of psoriatic patients are dyslipidemic, this finding is of clinical significance and indicates that self-lipid-reactive T cells might serve as a possible link between hyperlipidemia and psoriasis.

C1q ablation exacerbates amyloid deposition: A study in a transgenic mouse model of ATTRV30M amyloid neuropathy.

ATTRV30M amyloid neuropathy is a lethal autosomal dominant sensorimotor and autonomic neuropathy, caused by deposition of amyloid fibrils composed of aberrant transthyretin (TTR). Ages of onset and penetrance exhibit great variability and genetic factors have been implicated. Complement activation co-localizes with amyloid deposits in amyloidotic neuropathy and is possibly involved in the kinetics of amyloidogenesis. A candidate gene approach has recently identified C1q polymorphisms to correlate with disease onset in a Cypriot cohort of patients with ATTRV30M amyloid neuropathy. In the current study we use a double transgenic mouse model of ATTRV30M amyloid neuropathy in which C1q is ablated to elucidate further a possible modifier role for C1q. Amyloid deposition is found to be increased by 60% in the absence of C1q. Significant up regulation is also recorded in apoptotic and cellular stress markers reflecting extracellular toxicity of pre-fibrillar and fibrillar TTR. Our data further indicate that in the absence of C1q there is marked reduction of macrophages in association with amyloid deposits and thus less effective phagocytosis of TTR.

Immunological alteration & toxic molecular inductions leading to cognitive impairment & neurotoxicity in transgenic mouse model of Alzheimer's disease

AimsInflammation is considered to be one of the crucial pathological factors associated with the development of Alzheimer's disease, although supportive experimental evidence remains undiscovered. Therefore, the current study was carried out to better understand and establish the pathophysiological involvement of chronic inflammation in a double transgenic mouse model of Alzheimer's disease. Main methodsWe analyzed amyloid-beta deposition, oxidative stress, biochemical, neurochemical and immunological markers in a 10month old (APΔE9) mouse model. Memory functions were assessed by behavioral testing followed by measurement of synaptic plasticity via extracellular field recordings. Key findingsSubstantial increases in amyloid-beta levels, beta-secretase activity, and oxidative stress, along with significant neurochemical alterations in glutamate and GABA levels were detected in the brain of APΔE9 mice. Interestingly, marked elevations of pro-inflammatory cytokines in whole brain lysate of APΔE9 mice were observed. Flow cytometric analysis revealed a higher frequency of CD4+ IL-17a and IFN-γ secreting T-cells in APΔE9 brain, indicating a robust T-cell infiltration and activation. Behavioral deficits in learning and memory tasks, along with impairment in long-term potentiation and associated biochemical changes in the expression of glutamatergic receptor subunits were evident. SignificanceThus, this study establishes the role by which oxidative stress, alterations in glutamate and GABA levels and inflammation increases hippocampal and cortical neurotoxicity resulting in the cognitive deficits associated with Alzheimer's disease.

Reduced acoustic startle response and peripheral hearing loss in the 5xFAD mouse model of Alzheimer's disease.

Hearing dysfunction has been associated with Alzheimer's disease (AD) in humans, but there is little data on the auditory function of mouse models of AD. Furthermore, characterization of hearing ability in mouse models is needed to ensure that tests of cognition that use auditory stimuli are not confounded by hearing dysfunction. Therefore, we assessed acoustic startle response and pre-pulse inhibition in the double transgenic 5xFAD mouse model of AD from 3-4 to 16 months of age. The 5xFAD mice showed an age-related decline in acoustic startle as early as 3-4 months of age. We subsequently tested auditory brainstem response (ABR) thresholds at 4 and 13-14 months of age using tone bursts at frequencies of 2-32 kHz. The 5xFAD mice showed increased ABR thresholds for tone bursts between 8 and 32 kHz at 13-14 months of age. Finally, cochleae were extracted and basilar membranes were dissected to count hair cell loss across the cochlea. The 5xFAD mice showed significantly greater loss of both inner and outer hair cells at the apical and basal ends of the basilar membrane than wild-type mice at 15-16 months of age. These results indicate that the 5xFAD mouse model of AD shows age-related decreases in acoustic startle responses, which are at least partially due to age-related peripheral hearing loss. Therefore, we caution against the use of cognitive tests that rely on audition in 5xFAD mice over 3-4 months of age, without first confirming that performance is not confounded by hearing dysfunction.

Early Contextual Fear Memory Deficits in a Double-Transgenic Amyloid-β Precursor Protein/Presenilin 2 Mouse Model of Alzheimer's Disease.

Presenilin 1 and presenilin 2 (PS1 and PS2) play a critical role in γ-secretase-mediated cleavage of amyloid-β precursor protein (APP) and the subsequent generation of β-amyloid peptides. The purpose of the present study was to test whether PS2 mutation accelerates the onset of contextual fear memory deficits in a mouse model of AD that expresses a mutation (K670N/M671L) of the human APP with the Swedish mutation (Tg2576 mice). In the present study, an APP/PS2 double-transgenic mouse model (PS2Tg2576) was generated by crossbreeding transgenic mice carrying the human mutant PS2 (N141I) with Tg2576 mice. Contextual fear conditioning was tested in PS2Tg2576 mice aged 3, 4, 6, and 10–12 months. PS2Tg2576 mice showed a tendency of lower freezing behavior as early as 3 months of age, but significant memory impairment was observed from the age of 4 months. The cognitive impairment was more prominent at ages of 6 and 10–12 months. In contrast, Tg2576 mice aged 3 and 4 months exhibited successful acquisition of contextual fear learning, but Tg2576 mice aged 6 months or older showed significantly impaired fear memory. These results show that PS2 mutation significantly accelerates the onset of fear memory deficits in the APP AD model mice.

Exploring the Role of the Recurrent Exportin 1 (XPO1/CRM1) Mutations E571G and E571K in Chronic Lymphocytic Leukemia

BackgroundExportin 1 (XPO1/CRM1) is a critical component of the nuclear to cytoplasmic export machinery. As such, XPO1 shuttles tumor suppressor proteins (e.g. p53, IkB) out of the nucleus thereby preventing their anti-apoptotic function and contributing to enhanced proliferation. XPO1 also transports a subset of mRNAs (e.g. c-fos, IFN-alpha) by virtue of 3'-UTR AU-rich elements. XPO1 is upregulated in most hematologic malignancies, including CLL, where elevated XPO1 expression correlates with poor prognosis and resistance to therapy. To date, the role of nuclear export in CLL is poorly understood. Interestingly, recurrent mutations at a highly conserved residue (E571G; E571K) in the cargo binding pocket of XPO1 have been described in chronic lymphocytic leukemia (CLL) and are associated with worse overall survival. We hypothesized that the E571G/K mutation confers novel cargo-binding abilities to XPO1 and may contribute to the pathogenesis of CLL.MethodsTo interrogate this question in an unbiased, transcriptome-wide manner we developed CLL cell lines expressing mutant XPO1 and a novel RNA immunoprecipitation procedure using RNase I digestion followed by RNA-seq to capture direct interaction sites or 'footprints'. Reads were mapped to the transcriptome and peaks (regions where RNA footprints are enriched) were identified. We examined footprints for enriched sequence motifs using the MEME suite. Mass-array screening identified a cohort of CLL patients bearing the E571G/K mutation for validation purposes. The XPO1 transgenic mice were generated via pronuclear injection of linearized plasmid containing human cDNA corresponding to XPO1WT, XPO1E571G, or XPO1E571K under the heavy chain promoter/enhancer.ResultsWe identified a transcriptome-wide pool of >100 XPO1-interacting RNAs in CLL cells and identified RNA footprints of wild-type XPO1 contributing to the first XPO1 RNA profile of a cell line model of CLL. The majority of bound RNA species associated with XPO1 are ribosomal, as expected; however, we identified multiple additional classes of RNAs such as miRs, mRNA, long-non coding RNAs, and many un-annotated RNAs. These data are consistent with additional preliminary data we have generated indicating that XPO1 may regulate mRNAs important in CLL development. We are currently searching for structural motifs. Validation experiments using patient-derived CLL cells with and without XPO1 mutations are ongoing.To further assess the independent transforming role of XPO1 dysfunction in B-cells, we generated transgenic mice overexpressing XPO1WT, XPO1E571G, or XPO1E571K under the heavy chain promoter/enhancer in the B cell compartment of C57BL/6 mice. Overexpression of XPO1 at the protein level in B cells was confirmed in multiple transgenic founder lines. Preliminary studies were performed to characterize the XPO1 transgenic animals for defects or alterations in major stages of B cell maturation. We analyzed the pro-B (IgM-CD43+), pre-B (IgM-CD43-), and immature (IgM+CD43-) B cell stages of development from the bone marrow of XPO1 transgenic animals and littermate controls. We also examined immature (IgM+IgD-) and mature (IgM+IgD+) B cells isolated from the spleen of these animals. In this preliminary analysis no significant differences in the B cell compartment were observed between transgenic and non-transgenic animals. Functional studies of these B-cells are ongoing. A cohort of animals from each founder line is being followed for evidence of B-cell expansion and overall survival analysis. In addition, the XPO1 transgenic mice were crossed with the Eµ-TCL1 mice to establish the XPO1WT/E571K/G/TCL1 double transgenic mouse model whose disease is currently being monitored.ConclusionsXPO1 is a recurring, high variant allele mutation that occurs in a small subset of CLL patients. XPO1 transports select mRNA and also novel RNA species whose function in CLL have yet to be characterized, but points to a novel role of this oncoprotein in the pathogenesis of this disease. DisclosuresNo relevant conflicts of interest to declare.

Novel model of double transgenic mouse results in autoimmune diabetes in males

Identifying the type of diabetogenic CD8+ T cells that initiate autoimmune diabetes (AID) is a critical step in designing appropriate strategies for the early detection of beta cell-directed autoimmunity and its progression to diabetes. We generated a novel double transgenic (Tg) mouse model on the naturally diabetes resistant C57Bl/6 background, co-expressing two transgenes including a specific TCR anti-lymphocytic choriomeningitis virus nucleoprotein (LCMV-NP) carried by CD8+ T cells and LCMV-NP (as neo-self antigen) expressed by pancreatic beta cells. The resulting double Tg mouse showed partial thymic deletion of the NP-specific CD8+ T cells. The escaping autoreactive NP-specific CD8+ T cells joining the periphery were activated and gained effector functions. Both male and female mice mounted anti-NP antibodies, but only one-fourth adult males spontaneously developed AID. Significant upregulation of the CD44 and CD122 markers as compared to healthy male and female mice characterized the phenotype of diabetogenic CD8+ T cells in diabetic male mice. We also show that only 10% of these CD8+ T cells expressed programmed death 1 receptor (PD-1). Together, these results suggest that in our double Tg mouse model, Ag-specific effector CD44+CD122+PD-1−CD8+ T cell subpopulation is associated with the pathogenesis of AID.

CD1b-autoreactive T cells recognize phospholipid antigens and contribute to antitumor immunity against a CD1b+ T cell lymphoma

ABSTRACTAdoptive immunotherapy for cancer treatment is an emerging field of study. Till now, several tumor-derived, peptide-specific T cell responses have been harnessed for treating cancers. However, the contribution of lipid-specific T cells in tumor immunity has been understudied. CD1 molecules, which present self- and foreign lipid antigens to T cells, are divided into group 1 (CD1a, CD1b, and CD1c) and group 2 (CD1d). Although the role of CD1d-restricted natural killer T cells (NKT) in several tumor models has been well established, the contribution of group 1 CD1-restricted T cells in tumor immunity remains obscure due to the lack of group 1 CD1 expression in mice. In this study, we used a double transgenic mouse model expressing human group 1 CD1 molecules (hCD1Tg) and a CD1b-restricted, self-lipid reactive T cell receptor (HJ1Tg) to study the potential role of group 1 CD1-restricted autoreactive T cells in antitumor response. We found that HJ1 T cells recognized phospholipids and responded more potently to lipid extracted from tumor cells than the equivalent amount of lipids extracted from normal cells. Additionally, the autoreactivity of HJ1 T cells was enhanced upon treatment with various intracellular toll-like receptor (TLR) agonists, including CpG oligodeoxynucleotides (ODN), R848, and poly (I:C). Interestingly, the adoptive transfer of HJ1 T cells conferred protection against the CD1b-transfected murine T cell lymphoma (RMA-S/CD1b) and CpG ODN enhanced the antitumor effect. Thus, this study, for the first time, demonstrates the antitumor potential of CD1b-autoreactive T cells and their potential use in adoptive immunotherapy.