Induction Of Memory Research Articles

Environmental stress and nanoplastics' effects on Ciona robusta: regulation of immune/stress-related genes and induction of innate memory in pharynx and gut.

In addition to circulating haemocytes, the immune system of the solitary ascidian Ciona robusta relies on two organs, the pharynx and the gut, and encompasses a wide array of immune and stress-related genes. How the pharynx and the gut of C. robusta react and adapt to environmental stress was assessed upon short or long exposure to hypoxia/starvation in the absence or in the presence of polystyrene nanoplastics. We show that the immune response to stress is very different between the two organs, suggesting an organ-specific immune adaptation to the environmental changes. Notably, the presence of nanoplastics appears to alter the gene modulation induced by hypoxia/starvation in both organs, resulting in a partial increase in gene up-regulation in the pharynx and a less evident response to stress in the gut. We have also assessed whether the hypoxia/starvation stress could induce innate memory, measured as gene expression in response to a subsequent challenge with the bacterial agent LPS. Exposure to stress one week before challenge induced a substantial change in the response to LPS, with a general decrease of gene expression in the pharynx and a strong increase in the gut. Co-exposure with nanoplastics only partially modulated the stress-induced memory response to LPS, without substantially changing the stress-dependent gene expression profile in either organ. Overall, the presence of nanoplastics in the marine environment seems able to decrease the immune response of C. robusta to stressful conditions, hypothetically implying a reduced capacity to adapt to environmental changes, but only partially affects the stress-dependent induction of innate memory and subsequent responses to infectious challenges.

Recalling Self-efficacious Memories Reduces COVID-19-Related Fear.

Manipulating perceived self-efficacy can mitigate the negative impact of trauma and increase ability to adapt to stress. It is possible that a similar domain-based manipulation aimed at anxiety around the pandemic might mitigate the negative mental health impact of COVID-19. The current experimental study assessed whether a self-efficacy induction would be effective in reducing COVID-19 distress. Participants were randomized to a self-efficacy autobiographical memory induction or control condition. We hypothesized that individuals in the self-efficacy group would exhibit lower levels of fear on an implicit measure of emotional states following exposure to COVID-19-related stimuli. A significant increase in general self-efficacy and self-confidence was found in the self-efficacy group from pre- to post-induction. Individuals in the self-efficacy group had significantly lower levels of fear counts on the implicit measure of emotional states than the control group following exposure to COVID-19-related stimuli. Results suggest that (1) self-efficacy can be increased among individuals with high levels of COVID-19-related distress using an autobiographical memory induction and (2) doing so reduces fear processing among these individuals when exposed to COVID-19 stimuli. This is relevant for future intervention as it reveals a possible mechanism for reducing and recovering from COVID-19-related distress. The online version contains supplementary material available at 10.1007/s10608-023-10377-6.

Intravenous BCG Induction of Innate Memory in Young Pigs

Abstract Exposure to vaccine strain of Mycobacterium bovis(M. bovis), Bacillus Calmette-Guerin (BCG), alters innate immune cells through epigenetic and metabolic modifications resulting in heightened responses to subsequent microbial insult (innate memory). As a biomedical model for human disease, pigs provide a critical space to study the role of innate memory in disease resistance. Young pigs were inoculated intravenous (IV) or intraperitoneal (IP) with either live or heat-inactivated BCG (IV-live, IP-live, IV-inactive, noBCG groups). At 2wks post BCG inoculation, monocyte production of IL-1β nor TNF cytokines following ex vivostimulation with LPS was not different in any BCG group compared to noBCG, i.e. no innate memory. As dose of live BCG was lower than anticipated, at 3wks post primary inoculation, all pigs were inoculated a second time with respective preparations and routes of BCG. Ex vivocytokine production in LPS stimulated monocytes was measured again at 5wks post primary inoculation (2wks post-secondary inoculation) and both IL-1β and TNF cytokines were elevated in IV-live (innate memory), but not IP-live or IV-inactive groups. Additionally, ex vivostimulation of PBMC with homologous recall antigen (purified proteins from M. bovis) resulted in a 3-fold higher IFNγ response in IP-live compared to IV-live and no IFNγ production in noBCG or IV-inactive. Together these data suggest that while BCG can induce a state of innate memory in monocytes of young pigs, induction of training cannot be inferred by T cell production of IFNγ to recall protein antigen. Additionally, data continue to highlight pigs as a valuable model as multiple BCG factors (i.e. route, dose, or viability) may need to be considered for induction of innate memory. USDA-ARS CRIS project 5030-32000-225-000D

Identity of virus-specific and cross-reactive T cell memory to mpox

Abstract The unprecedented spread of mpox (previously known as monkeypox) in several countries worldwide has led the WHO to declare the mpox outbreak a global health emergency in 2022. T cell responses are likely to play a central role in the resolution of the mpox infection. However, the prevalence and phenotype of mpox-specific T cells have not been investigated in detail, and the extent of cross-reactive immunological memory following previous smallpox vaccination is not known. Here, we assessed T cell responses to mpox infection in n=22 convalescent patients and n=53 healthy blood donors of different age groups, using CD4- and CD8-targeted peptide pools and optimal peptides through activation-induced marker (AIM), functional, and tetramer assays. We observed considerable CD4 and CD8 T cell activation among mpox patients in response to the peptide pools. Surprisingly, we did not detect differences between age groups of non-infected donors, despite previous exposure of older individuals to smallpox vaccination. Investigation of n=3 mpox-cross-reactive immunodominant vaccinia epitopes revealed that memory cells, although present, were maintained at comparable frequencies to naïve T cell precursors in older individuals. CD8+ T cells specific for the cross-reactive epitopes were significantly expanded and acquired an effector memory phenotype of elevated T-bet and Granzyme-B levels after mpox infection. Our data demonstrate low magnitudes of cross-reactive T cells against mpox across different age groups, whereas mpox infection leads to robust induction of effector memory T cells with strong recall potential. Supported by SNF Post-doc mobility grant (P500PB_211069)

Tumor eradication by hetIL-15 locoregional therapy correlates with an induced intratumoral CD103intCD11b+ dendritic cell population

Locoregional monotherapy with heterodimeric interleukin (IL)-15 (hetIL-15) in a triple-negative breast cancer (TNBC) orthotopic mouse model resulted in tumor eradication in 40% of treated mice, reduction of metastasis, and induction of immunological memory against breast cancer cells. hetIL-15 re-shaped the tumor microenvironment by promoting the intratumoral accumulation of cytotoxic lymphocytes, conventional type 1 dendritic cells (cDC1s), and a dendritic cell (DC) population expressing both CD103 and CD11b markers. These CD103intCD11b+DCs share phenotypic and gene expression characteristics with both cDC1s and cDC2s, have transcriptomic profiles more similar to monocyte-derived DCs (moDCs), and correlate with tumor regression. Therefore, hetIL-15, a cytokine directly affecting lymphocytes and inducing cytotoxic cells, also has an indirect rapid and significant effect on the recruitment of myeloid cells, initiating a cascade for tumor elimination through innate and adoptive immune mechanisms. The intratumoral CD103intCD11b+DC population induced by hetIL-15 may be targeted for the development of additional cancer immunotherapy approaches.

ILC2-dependent induction of small intestinal memory and systemic mucosal resilience.

Abstract The IL-25-dependent ILC2-tuft cell circuit drives altered intestinal physiology in response to chronic helminth and protist infections. We optimized an induction regimen with recombinant IL-25 that resulted in long-lasting alterations of the small intestine, which we termed small intestinal memory. This state was characterized by expanded ILC2s and epithelial tuft cells, small intestinal lengthening, and enhanced resistance to helminth infection. ILC2s were necessary for the establishment of small intestinal memory, as this state was induced in Rag-deficient, but not Ragx gc-deficient mice or mice with deletion of IL-17RB on ILCs. ILC2s also maintained small intestinal memory, as this state was rapidly lost upon ILC2 ablation. Transcriptomic analysis revealed dynamic changes in ILC2 identities from IL-25-treated mice, demonstrative of innate memory. Strikingly, although these alterations were induced by IL-25, the ILC2 memory state was sustained in the absence of IL-25, tuft cells, or multiple alarmins like IL-33, TSLP, or IL-18. Finally, we found that small intestinal memory conferred resistance to bacterial and viral infections at distant mucosal sites and notably impacted the metabolic fitness of mice. The induction of enhanced mucosal resilience accompanied by increased metabolic fitness by IL-25 mimics the positive effects of chronic helminth infestation, revealing a mechanistic pathway that might underpin the widespread prevalence of these infections among vertebrates and that could be therapeutically adapted to improve mucosal health.

Hooked on a memory: How rumination about past positive events might contribute to grandiose ideas?

Dwelling about positive experiences has been found to be positively related to mania and grandiose ideas. Nevertheless, besides some important limitations, past research has also neglected the nature (or characteristics) of memories individuals dwell on, and that might be specifically associated with grandiose ideas. Thus, the present study aimed to replicate previous studies while considering the role of specificity and the importance of memory used to increase grandiose feelings. In total, 219 participants were included and, after completing the memory induction, were randomized to either the rumination condition or the distraction condition. They also completed different questionnaires assessing positive rumination and grandiose ideas. Overall, rumination, compared to the distraction condition, led to the maintenance of grandiose ideas and positive affect from T2 to T3. Regression analysis showed that the specificity of memory was associated with grandiose ideas at T2, which predicted grandiose ideas at T3. Our results confirm rumination's causal role in forming grandiose ideas. We also found that autobiographical memory and, more specifically, the capacity to recall past positive experiences coupled with repeatedly thinking about them might constitute a fundamental pathway leading to the persistence of such beliefs. The use of a non-clinical sample limits the results and needs replication in clinical samples.

Limited induction of polyfunctional lung-resident memory T cells against SARS-CoV-2 by mRNA vaccination compared to infection

Resident memory T cells (TRM) present at the respiratory tract may be essential to enhance early SARS-CoV-2 viral clearance, thus limiting viral infection and disease. While long-term antigen-specific TRM are detectable beyond 11 months in the lung of convalescent COVID-19 patients, it is unknown if mRNA vaccination encoding for the SARS-CoV-2 S-protein can induce this frontline protection. Here we show that the frequency of CD4+ T cells secreting IFNγ in response to S-peptides is variable but overall similar in the lung of mRNA-vaccinated patients compared to convalescent-infected patients. However, in vaccinated patients, lung responses present less frequently a TRM phenotype compared to convalescent infected individuals and polyfunctional CD107a+ IFNγ+ TRM are virtually absent in vaccinated patients. These data indicate that mRNA vaccination induces specific T cell responses to SARS-CoV-2 in the lung parenchyma, although to a limited extend. It remains to be determined whether these vaccine-induced responses contribute to overall COVID-19 control.

Abstract 4165: A systemically administered killed bacteria-based multiple immune receptor agonist for pulsed anti-tumor immunotherapy

Abstract Systemic activation of multiple immune receptors, such as Toll-like (TLR), NOD-like (NLR) and Stimulator of Interferon Genes (STING) is essential for efficient innate and adaptive immune responses. Attempts to use single receptor agonists for advanced cancers have not produced approved products. Limitations include insufficient immune activation and dose-limiting toxicities associated with continuous exposure. Gram-negative bacteria (G-NB) contain multiple TLR, NOD and STING agonists. Potential utility of G-NB for cancer immunotherapy is supported by observation of tumor regression in the setting of infection and Coley’s Toxins. Coley reported that i.v. administration was likely most effective but produced toxicity. The discovery of TLRs, particularly the broad/potent activities of the TLR4 agonist lipopolysaccharide (LPS) suggest that it may be both a critical active ingredient and a dose-limiting feature of i.v. G-NB. Non-pathogenic E. coli were treated with polymyxin to achieve ~90% reduction of LPS activity without lysis and were then killed and stabilized with glutaraldehyde. The resulting product, Decoy10, was shown to contain multiple TLR, NOD and STING agonists and exhibited reduced i.v. toxicity (mice, rabbits) relative to unprocessed cells. Surprisingly, despite reduction in LPS activity and toxicity, Decoy10 induced secretion of similar or higher levels of most cytokines/chemokines by peripheral blood mononuclear cells, compared to unprocessed bacteria. Higher cytokine/chemokine induction was also observed compared to monospecific TLR agonists. Administration of 4 to 8 weekly or twice a week i.v. doses of Decoy10 to mice with established s.c., orthotopic or metastatic syngeneic breast, colorectal, hepatocellular, pancreatic carcinomas or syngeneic or human non-Hodgkin’s lymphoma was well-tolerated and produced single agent anti-tumor activity and/or combination-mediated durable tumor regressions, with induction of immunological memory. Regressions were observed, without significantly increased toxicity, when Decoy10 was combined with chemotherapy, a non-steroidal anti-inflammatory drug, anti-PD-1 therapy or rituximab. Tumor regressions were associated with activation of innate and adaptive immune pathways in tumors after one dose of Decoy10 and were mediated by NK, CD4+ and CD8+ T cells. Published studies have demonstrated that systemic bacteria are engulfed by and activate immune cells in the liver and spleen, with rapid clearance in mice, rabbits, and humans. Systemic bacteria have also been shown to accumulate in or around tumors. We have taken advantage of these phenomena to produce a detoxified but potent multiple immune agonist that induces systemic innate and adaptive anti-tumor immune activation without requirement for continuous systemic exposure. A Decoy product has been cleared by the US FDA for a Phase 1 oncology trial. Citation Format: Michael J. Newman. A systemically administered killed bacteria-based multiple immune receptor agonist for pulsed anti-tumor immunotherapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4165.

Abstract 1809: ACT-1002-4391 - A novel potent antagonist of the prostaglandin E2 receptors EP2 and EP4 with excellent duality

Abstract Prostaglandin E2 (PGE2) binds to four G-protein-coupled EP receptors, of which both EP2 and EP4 are abundantly expressed by tumor-infiltrating immune cells including DCs, NK cells, Tregs, cytotoxic T cells and TAMs. Signaling via EP2 and EP4 is immunosuppressive, preventing the mounting of effective anti-tumor immune responses leading to tumor immune escape and tumor progression. Currently, several EP4 selective antagonists and an EP2/4 dual antagonist are being developed for anti-cancer immunotherapy. Using a combination of EP2 and EP4 selective antagonists in different tumor mouse models, we could demonstrate that dual EP2/EP4 blockade is more effectively activating anti-tumor immunity compared to targeting either receptor alone. The concurrent inhibition of EP2 and EP4 resulted in tumor regression and induction of immunological memory. Together with published data showing similar findings, our results suggest that simultaneous targeting of EP2 and EP4 could be a promising new therapeutic approach to overcome cancer immune evasion. Idorsia Pharmaceuticals has identified ACT-1002-4391 as a novel, potent antagonist of EP2 and EP4 receptors with an excellent duality profile. In vitro, ACT-1002-4391 is capable of modulating immune cell proliferation and/or function and is superior to EP2 or EP4 selective inhibition in that respect. In vivo, ACT-1002-4391 displays strong and dose-dependent single agent anti-tumor efficacy in a syngeneic mouse tumor model. Based on the excellent selectivity and duality profile, ACT-1002-4391 will be advanced into clinical development by Idorsia Pharmaceuticals. Citation Format: Sébastien Jeay, Stefan Diethelm, Agnes Knopf, Marie Goxe, Marie Daugan, Julie Erupathil, Julien Pothier, Davide Pozzi, Thierry Sifferlen, Lorenza Wyder, Isabelle Lyothier, Olivier Corminboeuf, Francois Lehembre, Imke Renz, Dominique Meyer. ACT-1002-4391 - A novel potent antagonist of the prostaglandin E2 receptors EP2 and EP4 with excellent duality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1809.

Maintenance and recall of memory T cell populations against tuberculosis: Implications for vaccine design.

Despite the widespread use of standardised drug regimens, advanced diagnostics, and Mycobacterium bovis Bacille-Calmette-Guérin (BCG) vaccines, the global tuberculosis (TB) epidemic remains uncontrollable. To address this challenge, improved vaccines are urgently required that can elicit persistent immunologic memory, the hallmark of successful vaccines. Nonetheless, the processes underlying the induction and maintenance of immunologic memory are not entirely understood. Clarifying how memory T cells (Tm cells) are created and survive long term may be a crucial step towards the development of effective T cell-targeted vaccines. Here, we review research findings on the memory T cell response, which involves mobilization of several distinct Tm cell subsets that are required for efficient host suppression of M. tuberculosis (Mtb) activity. We also summaries current knowledge related to the T cell response-based host barrier against Mtb infection and discuss advantages and disadvantages of novel TB vaccine candidates.

Tumor-targeted superantigens produce curative tumor immunity with induction of memory and demonstrated antigen spreading

BackgroundDespite remarkable progress, the immunotherapies currently used in the clinic, such as immune checkpoint blockade (ICB) therapy, still have limited efficacy against many types of solid tumors. One major barrier to effective treatment is the lack of a durable long-term response. Tumor-targeted superantigen (TTS) therapy may overcome this barrier to enhance therapeutic efficacy. TTS proteins, such as the clinical-stage molecule naptumomab estafenatox (NAP), increase tumor recognition and killing by both coating tumor cells with bacterial-derived superantigens (SAgs) and selectively expanding T-cell lineages that can recognize them. The present study investigated the efficacy and mechanism of action of repeated TTS (C215Fab-SEA) treatments leading to a long-term antitumor immune response as monotherapy or in combination with PD-1/PD-L1 inhibitors in murine tumor models.MethodsWe used syngeneic murine tumor models expressing the human EpCAM target (C215 antigen) to assess the efficacy and mechanism of action of repeated treatment with TTS C215Fab-SEA alone or with anti-PD-1/PD-L1 monoclonal antibodies. Tumor draining lymph nodes (TDLNs) and tumor tissues were processed and analyzed by immunophenotyping and immunohistochemistry. Isolated RNA from tumors was used to analyze gene expression and the TCR repertoire. Tumor rechallenge and T-cell transfer studies were conducted to test the long-term antitumor memory response.ResultsTTS therapy inhibited tumor growth and achieved complete tumor rejection, leading to a T-cell-dependent long-term memory response against the tumor. The antitumor effect was derived from inflammatory responses converting the immunosuppressive TME into a proinflammatory state with an increase in T-cell infiltration, activation and high T-cell diversity. The combination of TTS with ICB therapy was significantly more effective than the monotherapies and resulted in higher tumor-free rates.ConclusionsThese new results indicate that TTSs not only can turn a “cold” tumor into a “hot” tumor but also can enable epitope spreading and memory response, which makes TTSs ideal candidates for combination with ICB agents and other anticancer agents.

Beta variant COVID-19 protein booster vaccine elicits durable cross-neutralization against SARS-CoV-2 variants in non-human primates

The rapid spread of the SARS-CoV-2 Omicron subvariants, despite the implementation of booster vaccination, has raised questions about the durability of protection conferred by current vaccines. Vaccine boosters that can induce broader and more durable immune responses against SARS-CoV-2 are urgently needed. We recently reported that our Beta-containing protein-based SARS-CoV-2 spike booster vaccine candidates with AS03 adjuvant (CoV2 preS dTM-AS03) elicited robust cross-neutralizing antibody responses at early timepoints against SARS-CoV-2 variants of concern in macaques primed with mRNA or protein-based subunit vaccine candidates. Here we demonstrate that the monovalent Beta vaccine with AS03 adjuvant induces durable cross-neutralizing antibody responses against the prototype strain D614G as well as variants Delta (B.1.617.2), Omicron (BA.1 and BA.4/5) and SARS-CoV-1, that are still detectable in all macaques 6 months post-booster. We also describe the induction of consistent and robust memory B cell responses, independent of the levels measured post-primary immunization. These data suggest that a booster dose with a monovalent Beta CoV2 preS dTM-AS03 vaccine can induce robust and durable cross-neutralizing responses against a broad spectrum of variants.

Neoadjuvant immunotherapy for colorectal cancer: Right regimens, right patients, right directions?

Neoadjuvant chemoradiotherapy (NACRT) or chemotherapy (NACT) followed by radical resection and then adjuvant therapy is considered the optimal treatment model for locally advanced colorectal cancer (LACRC). A recent total neoadjuvant therapy (TNT) strategy further improved the tumour regression rate preoperatively and reduced local-regional recurrence in locally advanced rectal cancer (LARC). However, distant metastasis was still high, and little overall survival benefit was obtained from these preoperative treatment models. According to mismatch repair protein expression, MSI-H/dMMR and non-MSI-H/pMMR statuses were defined in colorectal cancer (CRC) patients. Due to the special features of biologics in MSI-H/dMMR CRC patients, this subgroup of patients achieved little treatment efficacy from chemoradiotherapy but benefited from immune checkpoint inhibitors (ICIs). The KEYNOTE-177 trial observed favourable survival outcomes in metastatic CRC patients treated with one-line pembrolizumab with tolerable toxicity. Given the better systemic immune function, increased antigenic exposure, and improved long-term memory induction before surgery, neoadjuvant ICI (NAICI) treatment was proposed. The NICHE trial pioneered the use of NAICI treatment in LACRC, and recent reports from several phase II studies demonstrated satisfactory tumour downsizing in CRC. Preclinical rationales and preliminary early-phase human trials reveal the feasibility of NAICI therapy and the therapeutic efficacy provided by this treatment model. Better tumour regression before surgery also increases the possibility of organ preservation for low LARC. However, the optimal treatment strategy and effective biomarker identification for beneficiary selection remain unknown, and potential pitfalls exist, including tumour progression during neoadjuvant treatment due to drug resistance and surgery delay. Given these foundations and questions, further phase II or III trials with large samples need to be conducted to explore the right regimens for the right patients.

Changes in the Population of Immature Neurons in the Pyriform Cortex of Experimental Animals after Early Life Stress

Early life stress is an important factor predisposing to the development of pathology of the nervous system in animals and humans in the late period of ontogenesis. We used an early life stress model to assess the activation of the piriform cortex upon presentation of olfactory stimuli in experimental animals (CD1 mice, P60 and 10 months old) as well as to assess the expression of markers of neurons with prolonged immaturity involved in the processes of plasticity of the adult brain and its recovery. We found that early life stress reduces the number of immature neurons with the DCX+PSA-NCAM+ phenotype in the piriform cortex and the response to olfactory memory induction. In addition, olfactory stimulation reduces sensitivity to unpleasant stimuli at a young age (P60), stimulates short-term memory. However, at the age of 10 months, these effects are less evident. The results obtained indicate a possible contribution of immature neurons of the piriform cortex to the mechanisms of aberrant neuroplasticity after early life stress.

Glucocorticoid-Responsive Tissue Plasminogen Activator (tPA) and Its Inhibitor Plasminogen Activator Inhibitor-1 (PAI-1): Relevance in Stress-Related Psychiatric Disorders.

Stressful events trigger a set of complex biological responses which follow a bell-shaped pattern. Low-stress conditions have been shown to elicit beneficial effects, notably on synaptic plasticity together with an increase in cognitive processes. In contrast, overly intense stress can have deleterious behavioral effects leading to several stress-related pathologies such as anxiety, depression, substance use, obsessive-compulsive and stressor- and trauma-related disorders (e.g., post-traumatic stress disorder or PTSD in the case of traumatic events). Over a number of years, we have demonstrated that in response to stress, glucocorticoid hormones (GCs) in the hippocampus mediate a molecular shift in the balance between the expression of the tissue plasminogen activator (tPA) and its own inhibitor plasminogen activator inhibitor-1 (PAI-1) proteins. Interestingly, a shift in favor of PAI-1 was responsible for PTSD-like memory induction. In this review, after describing the biological system involving GCs, we highlight the key role of tPA/PAI-1 imbalance observed in preclinical and clinical studies associated with the emergence of stress-related pathological conditions. Thus, tPA/PAI-1 protein levels could be predictive biomarkers of the subsequent onset of stress-related disorders, and pharmacological modulation of their activity could be a potential new therapeutic approach for these debilitating conditions.

Compensatory Contextual Fear Memory Pathways Develop in the Infralimbic Cortex within 3 Days after the First Test in the Absence of the Dorsal Hippocampus.

The dorsal hippocampus (DH) is primarily involved in the formation of contextual fear-conditioned (CxFC) memory. However, CxFC memory can be formed even in the absence of the DH. In addition to the DH, the infralimbic cortex (IL), a sub-region of the medial prefrontal cortex (mPFC), also plays an important role in the consolidation of CxFC memory. However, role of IL in the development of compensatory CxFC memory is not known. Here, we have examined (a) the development of the compensatory circuitry of CxFC memory within 3 days after the first test in the absence of the DH and (b) the role of IL in the induction of compensatory CxFC memory in the absence of the DH. The DH-lesioned rats re-trained for CxFC 1 day after the first testing exhibited significantly less freezing compared to the control group. However, the DH-lesioned rats, re-trained for CxFC 3 days after the first testing, showed a robust freezing response. It suggests that the fully functional compensatory circuitry of contextual fear memory develops after multiple training separated by 3 days. Furthermore, we observed that reversible inactivation of the IL of the DH-lesioned rats during the first training waned the formation of compensatory CxFC. It suggests that (a) the IL receives contextual fear memory information during the first trial in the absence of the DH and (b) perturbation in fear memory information encoding in the IL during the first trial impairs the development of the compensatory network in the absence of the DH.

Multi-antigen spherical nucleic acid cancer vaccines.

Cancer vaccines must activate multiple immune cell types to be effective against aggressive tumours. Here we report the impact of the structural presentation of two antigenic peptides on immune responses at the transcriptomic, cellular and organismal levels. We used spherical nucleic acid (SNA) nanoparticles to investigate how the spatial distribution and placement of two antigen classes affect antigen processing, cytokine production and the induction of memory. Compared with single-antigen SNAs, a single dual-antigen SNA elicited a 30% increase in antigen-specific T cell activation and a two-fold increase in T cell proliferation. Antigen placement within dual-antigen SNAs altered the gene expression of T cells and tumour growth. Specifically, dual-antigen SNAs encapsulating antigens targeting helper T cells and with externally conjugated antigens targeting cytotoxic T cells elevated antitumour genetic pathways, stalling lymphoma tumours in mice. Additionally, when combined with the checkpoint inhibitor anti-programmed-cell-death protein-1 in a mouse model of melanoma, a specific antigen arrangement within dual-antigen SNAs suppressed tumour growth and increased the levels of circulating memory T cells. The structural design of multi-antigen vaccines substantially impacts their efficacy.

Nasal Tumor Vaccination Protects against Lung Tumor Development by Induction of Resident Effector and Memory Anti-Tumor Immune Responses.

Lung metastasis is a leading cause of cancer-related deaths. Here, we show that intranasal delivery of our engineered CpG-coated tumor antigen (Tag)-encapsulated nanoparticles (NPs)-nasal nano-vaccine-significantly reduced lung colonization by intravenous challenge of an extra-pulmonary tumor. Protection against tumor-cell lung colonization was linked to the induction of localized mucosal-associated effector and resident memory T cells as well as increased bronchiolar alveolar lavage-fluid IgA and serum IgG antibody responses. The nasal nano-vaccine-induced T-cell-mediated antitumor mucosal immune response was shown to increase tumor-specific production of IFN-γ and granzyme B by lung-derived CD8+ T cells. These findings demonstrate that our engineered nasal nano-vaccine has the potential to be used as a prophylactic approach prior to the seeding of tumors in the lungs, and thereby prevent overt lung metastases from existing extra pulmonary tumors.

CD28-CAR-T cell activation through FYN kinase signaling rather than LCK enhances therapeutic performance

Signal transduction induced by chimeric antigen receptors (CARs) is generally believed to rely on the activity of the SRC family kinase (SFK) LCK, as is the case with Tcell receptor (TCR) signaling. Here, we show that CAR signaling occurs in the absence of LCK. This LCK-independent signaling requires the related SFK FYN and a CD28 intracellular domain within the CAR. LCK-deficient CAR-T cells are strongly signaled through CAR and have better invivo efficacy with reduced exhaustion phenotype and enhanced induction of memory and proliferation. These distinctions can be attributed to the fact that FYN signaling tends to promote proliferation and survival, whereas LCK signaling promotes strong signaling that tends to lead to exhaustion. This non-canonical signaling of CAR-T cells provides insight into the initiation of both TCR and CAR signaling and has important clinical implications for improvement of CAR function.