Enriched CD45RA−CD62L+ central memory T and decreased CD3+CD56+ natural killer T lymphocyte subsets in the rectum of ulcerative colitis patients

Objectives To investigate the distinctive features of lymphocytes promoting inflammation in ulcerative colitis. Methods We performed flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) and colorectal mucosa lymphocytes in ulcerative colitis patients ( n = 13) and control patients ( n = 5). Results CD62L+/CD3+CD4+ (35.7 ± 14.0% vs. 19.9 ± 6.4%) and CD62L+/CD3+CD4− cells (17.1 ± 17.4% vs. 2.4 ± 3.9%) were higher in the rectum of ulcerative colitis patients than in control patients. Subpopulation analysis revealed that CD45RA−CD62L+/CD3+CD4+, that is, central memory T cell fraction in CD4+ T cells, was significantly increased in the rectum of ulcerative colitis, compared to that in control patients (23.3 ± 10.5% vs. 8.2 ± 4.0%). Comparison of rectum and colon samples in ulcerative colitis patients indicated that CD56+/CD3+ was decreased in the rectum compared to that in the colon (11.3 ± 12.5% vs. 21.3 ± 16.5%). The ratio of CD56+/CD3+ was also decreased in the rectum of active ulcerative colitis patients compared to that in ulcerative colitis patients at the endoscopic remission stages (2.8 ± 1.7% vs. 18.5 ± 13.3%). Conclusion We demonstrated that CD62L+ T lymphocytes, particularly the CD45RA−CD62L+ T cell subset that represents central memory T cells, were increased in the rectum of patients with ulcerative colitis. In addition, the CD56+/CD3+ subset (natural killer T cells) was decreased in the rectum compared to that of less inflamed colonic mucosa. These results suggest that the enrichment of central memory T lymphocytes and the reduction of natural killer T cells in the gut mucosa are involved in the pathogenesis of ulcerative colitis.

Anti-Inflammatory Mechanism of Astragaloside IV in the Recurrence of Asthma: Critical Role of Memory T Cells and OX40/OX40L Signaling Pathway

The recurrence of asthma is partly mediated by central memory CD4(+) T cells(TCM) that promote lung inflammation through the production of effector T cells. Targeting the expansion of pathogenic TCM(central memory CD4(+) T cells) is a promising therapeutic strategy to block production of effector T cells. The study aimed to evaluate the regulatory effects of Astragaloside IV (AS-IV) on TCMs and try to explore the anti-inflammatory mechanism of AS-IV in asthmatic mice. We developed a murine model of asthma by ovalbumin(OVA) challenge. Flow cytometry was used to determine the counts of CD4(+) memory T cells subgroups. Pulmonary tests, inflammatory cytokines in blood and inflammatory cells in bronchoalveolar lavage fluid,were measured to evaluate the inflammatory response level before and after AS-IV treatment. To further determine the role of TCM in the recurrence of inflammation, TCM were isolated by Magnetic-activated cell sorting (MACS) from spleens of asthma, control, AS-IV and dexamethasone treatment mice. The isolated cells were adoptive transferred into nude mice via tail intravenous injection, respectively, and the inflammatory response level of the lung was measured after OVA challenge. The effects of AS-IV on TCM viability, the number of the frequency (in percent) of CD44highCD62Lhigh cells, and the expression of OX40 and OX40L were measured before and after AS-IV treatment. In circulation blood, we demonstrated increased percentages of CCR7highCD62LlowCD4+ effector memory T cells(TEM) and decreased CCR7highCD62LhighCD4(+) TCM in asthma mice. On the contrary, the TEM subgroup percentage were decreased and the TCM phenotypes were increased in asthmatic spleen. AS-IV treatment significantly decreased CD4(+) T effector phenotypes in blood and inhibited the lung inflammatory response. Additionally, the inflammation of nude mice that adoptive transferred TCM from AS-IV treatment asthmatic mice had relieved inflammation compared with asthmatic group. In vitro, we successfully used spleen T lymphoid cells stimulated with IL-7 and OVA to induce a central memory T cell model. TCM co-cultured with DC cells had a significantly increased expression of OX40/OX40L. AS-IV pretreatment partially inhibited the expression of OX40 signal pathway. This study indicates that AS-IV can ameliorate asthma inflammation by inhibiting the production of TEM form TCM. The treatment mechanism maybe involved in the OX40/OX40L pathway.

Comparison of the Development of SARS-Coronavirus-2-Specific Cellular Immunity, and Central Memory CD4+ T-Cell Responses Following Infection versus Vaccination

Memory T-cell responses following infection with coronaviruses are reportedly long-lived and provide long-term protection against severe disease. Whether vaccination induces similar long-lived responses is not yet clear since, to date, there are limited data comparing memory CD4+ T-cell responses induced after SARS-CoV-2 infection versus following vaccination with BioNTech/Pfizer BNT162b2. We compared T-cell immune responses over time after infection or vaccination using ELISpot, and memory CD4+ T-cell responses three months after infection/vaccination using activation-induced marker flow cytometric assays. Levels of cytokine-producing T-cells were remarkably stable between three and twelve months after infection, and were comparable to IFNγ+ and IFNγ+IL-2+ T-cell responses but lower than IL-2+ T-cell responses at three months after vaccination. Consistent with this finding, vaccination and infection elicited comparable levels of SARS-CoV-2 specific CD4+ T-cells after three months in addition to comparable proportions of specific central memory CD4+ T-cells. By contrast, the proportions of specific effector memory CD4+ T-cells were significantly lower, whereas specific effector CD4+ T-cells were higher after infection than after vaccination. Our results suggest that T-cell responses—as measured by cytokine expression—and the frequencies of SARS-CoV-2-specific central memory CD4+T-cells—indicative of the formation of the long-lived memory T-cell compartment—are comparably induced after infection and vaccination.

Depletion of central memory CD8+ T cells might impede the antitumor therapeutic effect of Mogamulizumab

Regulatory T (Treg) cells are important negative regulators of immune homeostasis, but in cancers they tone down the anti-tumor immune response. They are distinguished by high expression levels of the chemokine receptor CCR4, hence their targeting by the anti-CCR4 monoclonal antibody mogamulizumab holds therapeutic promise. Here we show that despite a significant reduction in peripheral effector Treg cells, clinical responses are minimal in a cohort of patients with advanced CCR4-negative solid cancer in a phase Ib study (NCT01929486). Comprehensive immune-monitoring reveals that the abundance of CCR4-expressing central memory CD8+ T cells that are known to play roles in the antitumor immune response is reduced. In long survivors, characterised by lower CCR4 expression in their central memory CD8+ T cells possessed and/or NK cells with an exhausted phenotype, cell numbers are eventually maintained. Our study thus shows that mogamulizumab doses that are currently administered to patients in clinical studies may not differentiate between targeting effector Treg cells and central memory CD8+ T cells, and dosage refinement might be necessary to avoid depletion of effector components during immune therapy.

Distinct CD4−CD8− (Double-Negative) Memory T-Cell Subpopulations Are Associated With Indeterminate and Cardiac Clinical Forms of Chagas Disease

CD4−CD8− (double-negative, DN) T cells are critical orchestrators of the cytokine network associated with the pathogenic inflammatory response in one of the deadliest cardiomyopathies known, Chagas heart disease, which is caused by Trypanosoma cruzi infection. Here, studying the distribution, activation status, and cytokine expression of memory DN T-cell subpopulations in Chagas disease patients without cardiac involvement (indeterminate form—IND) or with Chagas cardiomyopathy (CARD), we report that while IND patients displayed a higher frequency of central memory, CARD had a high frequency of effector memory DN T cells. In addition, central memory DN T cells from IND displayed a balanced cytokine profile, characterized by the concomitant expression of IFN-γ and IL-10, which was not observed in effector memory DN T cells from CARD. Supporting potential clinical relevance, we found that the frequency of central memory DN T cells was associated with indicators of better ventricular function, while the frequency of effector memory DN T cells was not. Importantly, decreasing CD1d-mediated activation of DN T cells led to an increase in IL-10 expression by effector memory DN T cells from CARD, restoring a balanced profile similar to that observed in the protective central memory DN T cells. Targeting the activation of effector memory DN T cells may emerge as a strategy to control inflammation in Chagas cardiomyopathy and potentially in other inflammatory diseases where these cells play a key role.

Central Memory T-Cell Differentiation Correlates with Depth of Response in Relapsed/Refractory Multiple Myeloma Patients Receiving Elotuzumab in Combination with Carfilzomib, Lenalidomide and Dexamethasone (Elo-KRd)

Introduction: The addition of elotuzumab (Elo), an anti SLAMF7 immunostimulatory antibody, to carfilzomib, lenalidomide and dexamethasone (KRd) can lead to synergistic anti-myeloma immune effects. Pre-clinical data showed that both Elo and KRd promote innate NK cell response and adaptive cytotoxic T cell response. Here we report longitudinal NK and T cell profiling data in relation to clinical response and MRD status in the context of an Elo-KRd Phase II study (NCT03361306). Methods: Patients with relapsed refractory multiple myeloma (RRMM) after first-line therapy who enrolled in this phase II study received treatment with 4 cycles of Elo-KRd induction followed by Elo-Rd maintenance. Peripheral blood (PB) specimens were collected pre-induction (n=15), after induction (n=14), and every other month during maintenance (n=10). Bone marrow (BM) aspirates were collected pre- and post-induction and at the time of CR confirmation. Minimal residual disease (MRD) was assessed by next-generation flow cytometry (MRD NGF, 10 -5 sensitivity) post-induction for patients achieving very good partial response or better (≥VGPR). PB and BM NK, CD4 and CD8 T cell subset distribution, activation and anergy status were assessed by flow cytometry. Longitudinal Elo-KRd immune modulatory effect was modelled by polynomial regression analyses. Wilcoxon signed rank tests were used for timepoints comparisons. Mann-Whitney U tests were used for response groups comparisons between. Population frequency data, among mononuclear cells, are presented as mean±SD unless otherwise noted. Results: We first investigated Elo-KRd immune modulatory activity during induction treatment. Immature / mature NK cell distribution in PB remained unaltered pre- and post-induction (iNK: 8.9±6.4 vs 8.6±3.5, p=0.808; mNK: 14.9±6.8 vs 13.1±6.1, p=0.463). No significant change in PB NK activation markers KIR2DS4, KIR3DL1, NKG2A, NKG2D or NKp46 was observed throughout Elo-KRd induction. A lack of NK cell maturation was also observed in the BM despite a rise of iNK NKG2D expression (iNK NKG2D+: 22.5±7.7 vs 30.1±8.8, p=0.0.039). The number of both PB effector T helper (CD4+ Th) and cytotoxic T cell (CD8+ CTL) significantly decreased post-induction (PB ThEff: 28.5±16.4 vs 14.4±10.6, p<0.001; PB CTLEff: 58.6±19.7 vs 39.0±13.9, p=0.005), whereas CTL central memory cell counts increased (PB CTLCM 11.7±11.2 vs, 15.9±11.4 p=0.058). A similar effector to central memory T cell conversion was observed in BM and was more pronounced among CTL (BM CTLEff/CM ratio: 21.6±54.8 vs 2.1±1.6, p= 0.002). Overall response rate on study was 80%, with 53.5% (8/15) achieving ≥VGPR. MRD negativity rate (at 10-5 sensitivity) post-induction was 20% (3/15). The subset of patients who achieved ≥VGPR had higher rates of Th and CTL CM cell differentiation at baseline [≥VGPR vs <VGPR; PB ThEff/CM ratio: median 1.0 (range 0.1 - 1.5) vs 3.1 (0.8 - 212.1); p=0.018; PB CTLEff/CM ratio: median 4.1 (range 0.7 - 16.3) vs 13.2 (4.3 - 10607.1); p=0.056]. Among the MRD negative group, one patient remained in sustained CR at 38 months follow up and retained a high Th/CTL CM conversion rate throughout. At the time of relapse, PB (n=6) and BM (n=2) specimens were collected. While no significant alterations in PB NK cell maturation or activation were observed, circulating CTL Eff / CM distribution reverted to baseline levels (baseline vs relapse; PB CTLEff/CM ratio: 743.6±2755.1 vs 282.7±672.0; p=0.156). BM CTL cell effector / central memory distribution also tends to return to pre-induction levels. Conclusions: Unlike preclinical data where Elo has shown to enhance NK cell activity, longitudinal immune profiling analysis in patients with RRMM treated with Elo-KRd revealed limited activation of NK cell and no effect on NK cell maturation. Instead, we noted several changes within T cell compartment, notably activation and subsequent loss of Th and CTL effector cells, along with gain of central memory phenotype. This observation was most apparent for patients achieving ≥VGPR who exhibited significant higher rate of Effector to CM T cell conversion. On relapse, CM CTL cell frequency in both PB and BM compartments decreased to baseline level. Taken together, our results suggest that higher CM conversion rate, typically associated with sustained antigen stimulation, was associated with response to study treatment. Disclosures Foureau: Cytognos: Honoraria; TeneoBio, Celgene: Research Funding. Bhutani: Amgen, BMS, Takeda: Speakers Bureau; Sanofi: Consultancy; Janssen, MedImmune, Takeda, Celgene, BMS, Cerecor, Celularity: Research Funding. Atrash: GSK: Research Funding; AMGEN: Research Funding; Jansen: Research Funding, Speakers Bureau. Paul: Regeneron: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals Inc: Membership on an entity's Board of Directors or advisory committees; Amgen Inc.: Speakers Bureau; Bristol Myers Squibb: Divested equity in a private or publicly-traded company in the past 24 months. Symanowski: Eli Lilly: Consultancy, Other: DSMB Member; Immatics: Consultancy, Other: DSMB Member; Carsgen: Consultancy. Voorhees: Bristol-Myers Squibb Company.: Other: Data Safety & Monitoring; AbbVie Inc, Bristol-Myers Squibb Company; Consulting Agreement: GlaxoSmithKline, Novartis, Oncopeptides: Other: Advisory Committee. Usmani: EdoPharma: Consultancy; Janssen: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; Array BioPharma: Consultancy, Research Funding; Abbvie: Consultancy; GSK: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; Sanofi: Consultancy, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Janssen Oncology: Consultancy, Research Funding; Takeda: Consultancy, Research Funding, Speakers Bureau; SkylineDX: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding.

Deterministic Cell Separation Recovers >2-Fold T Cells, and More Naïve T Cells, for Autologous Cell Therapy As Compared to Centrifugally Prepared Cells

CAR-T autologous cell therapies are delivering impressive results in the clinic. However, there are still significant manufacturing challenges impeding the rapid adoption of these advanced therapies. On the first day of cell processing, most manufacturing approaches require ~5 steps (~4 hours) to obtain a white blood cell (WBC) preparation sufficiently depleted of red blood cells (RBCs) for T-cell selection and activation steps; and involves large cell losses and a great deal of inconsistency. Here we present a single-step procedure that yields >2 fold more cells that centrifugal processing with comparable or better quality in <1 hour. We previously reported a small-scale microfluidic approach using deterministic cell separation (DCS) to effectively isolate and separate WBCs with high recoveries, no loss of WBC subtypes, no cell damage, and greater numbers of central memory T cells than traditional Ficoll-based processing. Extending this work, we now present the results of our fully scaled-up processing of 23 normal donor leukopaks and 4 disease samples using a full-scale DCS prototype. All samples were processed in <45 minutes, with only an additional 10 minutes hands-on time. On average, inclusive of aggregate removal by prefiltering, DCS achieved 88% WBC recovery, 94% RBC removal, and 98% platelet ( PLT) removal from the undiluted leukopak samples (n=23). Furthermore, DCS resulted in a RBC/WBC ratio of 0.1 compared with a ratio of 1.4 for Ficoll. Similarly, the PLT/WBC ratios were 0.89 versus 7.17 for DCS and Ficoll, respectively (n=20). In addition, DCS preparations contained 2-fold more CD3+ T cells (n=17), and, importantly, the CD4+ cells were less differentiated (more cells in naïve and central memory stages) than those recovered by Ficoll. Similarly, DCS processed blood from cancer patients had a ratio of RBC/WBC = 7.0 versus 20.1 for Ficoll, and a PLT/WBC ratio = 0.7 versus 15.6 for Ficoll (n=4). These results demonstrate the capabilities of DCS in processing not only samples from normal donors but also blood from cancer patients with similar efficiencies. Further, with DCS we achieved wash efficiencies of more than 3 log, without the typically associated cell loss, as demonstrated by the removal of viral particles, soluble proteins and cytokines and growth factors present in plasma. Therefore, cells from leukopaks processed by DCS can be washed and collected directly into cell culture media, or other solutions, to ready them for downstream applications without pelleting and repeated washes, greatly simplifying workflows. We integrated our DCS technology into a full scale parallelized, disposable, closed fluid path solution and automated platform prototype, the Curate ® Cell Processing System, capable of processing undiluted leukopacks at rates in excess of 300mL/hour. Designed to process blood products in bags using a single-use cassette containing microfluidic components, the Curate ® delivers a debulked WBC product to a bag. With a hands-on time of only 10 minutes, the Curate ® reduces the time to activation- and expansion-ready cells from leukopaks by 6-fold as compared with centrifugation and elutriation methods (Bowles, et al. Cytotherapy 2018;20(5):S109). The system can process a full leukopak (200-300 mL containing up to 1.2x10 10 WBC) within 40 minutes with a maximal cell throughput of 1.8x10 10 WBC per hour. Additionally, the same Curate ® device can be used to achieve up to 200x10 6 cell/mL in as little as 40 mL of media and without requiring pelleting. In summary, we believe our technology enables a significant breakthrough in the production of CAR-T cells by efficiently recovering more and cleaner total and naÏve T cells, for CAR-T cell production. Furthermore, the closed-system Curate ® will simplify cell processing workflows by reducing the number of cell washing steps, as well as the hands-on time and resources. Supported in part by NIH Grant No 5R42CA228616-03 Disclosures Behmardi: GPB Scientific, Inc: Current Employment. Ouaguia: GPB Scientific, Inc: Current Employment. Healey: GPB Scientific, Inc: Current Employment. Jones: GPB Scientific, Inc: Current Employment. Rahmo: GPB Scientific, Inc: Current Employment. Skelley: GPB Scientific, Inc: Current Employment. Gandhi: GPB Scientific, Inc: Current Employment. Campos-Gonzalez: GPB Scientific, Inc: Current Employment, Current holder of stock options in a privately-held company. Civin: GPB Scientific, Inc: Current holder of individual stocks in a privately-held company. Ward: GPB Scientific, Inc: Current Employment.

Enhanced Infiltration of Central Memory T Cells to the Lung Tissue during Allergic Lung Inflammation

Memory T cells play a central role in regulating inflammatory responses during asthma. However, tissue distribution of effector memory (T_EM) and central memory (T_CM) T-cell subtypes, their differentiation, and their contribution to the persistence of lung tissue inflammation during asthma are not well understood. Interestingly, an increase in survival and persistence of memory T cells was reported in asthmatic lungs, which may suggest a shift toward the more persistent T_CM phenotype. In this report, we investigated the differential distribution of memory T-cell subtypes during allergic lung inflammation and the mechanism regulating that. Using an OVA-sensitized asthma mouse model, we observed a significant increase in the frequency of T_CM cells in inflamed lungs compared to healthy controls. Interestingly, adoptive transfer techniques confirmed substantial infiltration of T_CM cells to lung tissues during allergic airway inflammation. Expression levels of T_CM homing receptors, CD34 and GlyCAM-1, were also significantly upregulated in the lung tissues of OVA-sensitized mice, which may facilitate the increased T_CM infiltration into inflamed lungs. Moreover, a substantial increase in the relative expression of T_CM profile-associated genes (EOMES, BCL-6, ID3, TCF-7, BCL-2, BIM, and BMI-1) was noted for T_EM cells during lung inflammation, suggesting a shift for T_EM into the T_CM state. To our knowledge, this is the first study to report an increased infiltration of T_CM cells into inflamed lung tissues and to suggest differentiation of T_EM to T_CM cells in these tissues. Therapeutic interference at T_CM infiltration or differentiations could constitute an alternative treatment approach for lung inflammation.

CHARACTERIZATION OF CENTRAL AND EFFECTOR CD4⁺ MEMORY CELLS IN PSORIASIS

Psoriasis is a chronic autoimmune disease in which the skin and joints are involved in the pathological process. It was found that the recurrence of rashes in this disease occurs due to the resident memory cells of the skin. The number of CD4+CCR3+ effector memory cells in peripheral blood correlates with the severity of the disease. Therefore, the aim of our work is to study the phenotype of peripheral blood memory cells in patients with psoriasis.The study included 6 healthy donors: average age – 45.4 (min – 29, max – 55), women – 3, men – 3; 10 patients with psoriasis: women – 4, men – 6, average age – 37.3 (min – 23, max – 57), of which 5 patients with PASI > 10 and 5 patients with PASI < 10. The exclusion criteria for the study were the presence of autoimmune, oncological and hematological diseases, systemic therapy with immunosuppressive drugs for 1 month. Patients signed informed consent to participate in the study. Isolation of peripheral blood mononuclear cells was performed in a density gradient of ficoll-urographin (p = 1.082 g/L). Then cells were stained with fluorochrome-conjugated monoclonal antibodies to surface markers of central (Tcm) and effector (Tem) CD4+ memory cells (CD4, CD45RO, CD197), the α-chain of the IL-7 receptor (CD127), and the γ-chain of the IL-7 receptor (CD132). Statistical analysis of the data obtained was performed using the Statistica 6.0 software package.The percent of Tcm in the peripheral blood of donors was 33.4% (in – 18.2, max – 43.7), Tem – 28.7% (min – 13.6, max – 38.9), in patients with psoriasis: Tcm – 28.65% (min – 13.3, max – 59.6), Tem – 21.5% (min – 9.3, max – 38.6). In the peripheral blood of patients with psoriasis, among the central CD4+ memory cells, the proportion of CD127+CD132- -cells is 26.00%, CD127+CD132+ – 1.69%, CD127+CD132- – 69.00%, CD127- CD132+ – 1.94%. Among effector CD4+ memory cells, the proportion of CD127+CD132- -cells is 23.58%, CD127+CD132+ – 1.18%, CD127+CD132- – 69.84%, CD127- CD132+ – 0.70%. A direct correlation was found between the number of CD127- CD132+ central memory cells and the PASI value (r = 0.639, p < 0.05).In patients with psoriasis, the proportion of central memory cells is higher than in healthy donors, while the number of effector memory cells is lower. A direct correlation was found between the number of central cells expressing the γ-chain of the IL-7 receptor and the severity of the disease. Activated memory cells are characterized by high expression of CD132. It can be assumed that this population of memory cells plays a role in maintaining autoimmune inflammation in patients with this disease, and also participates in the repopulation of skin resident memory cells.