TCF1-positive and TCF1-negative TRM CD8 T cell subsets and cDC1s orchestrate melanoma protection and immunotherapy response.

BACKGROUND: Melanoma, the most lethal form of skin cancer, has undergone a transformative treatment shift with the advent of checkpoint blockade immunotherapy (CBI). Understanding the intricate network of immune cells infiltrating the tumor and orchestrating the control of melanoma cells and the response to CBI is currently of utmost importance. There is evidence underscoring the significance of tissue-resident memory (TRM) CD8 T cells and classic dendritic cell type 1 (cDC1) in cancer protection. Transcriptomic studies also support the existence of a TCF7+ (encoding TCF1) T cell as the most important for immunotherapy response, although uncertainty exists about whether there is a TCF1+TRM T cell due to evidence indicating TCF1 downregulation for tissue residency activation. METHODS: We used multiplexed immunofluorescence and spectral flow cytometry to evaluate TRM CD8 T cells and cDC1 in two melanoma patient cohorts: one immunotherapy-naive and the other receiving immunotherapy. The first cohort was divided between patients free of disease or with metastasis 2 years postdiagnosis while the second between CBI responders and non-responders. RESULTS: Our study identifies two CD8+TRM subsets, TCF1+ and TCF1-, correlating with melanoma protection. TCF1+TRM cells show heightened expression of IFN-γ and Ki67 while TCF1- TRM cells exhibit increased expression of cytotoxic molecules. In metastatic patients, TRM subsets undergo a shift in marker expression, with the TCF1- subset displaying increased expression of exhaustion markers. We observed a close spatial correlation between cDC1s and TRMs, with TCF1+TRM/cDC1 pairs enriched in the stroma and TCF1- TRM/cDC1 pairs in tumor areas. Notably, these TCF1- TRMs express cytotoxic molecules and are associated with apoptotic melanoma cells. Both TCF1+ and TCF1- TRM subsets, alongside cDC1, prove relevant to CBI response. CONCLUSIONS: Our study supports the importance of TRM CD8 T cells and cDC1 in melanoma protection while also highlighting the existence of functionally distinctive TCF1+ and TCF1- TRM subsets, both crucial for melanoma control and CBI response.

Strengthening Essential Health Services Recovery Policy after the COVID-19 Pandemic. Evidence from the Mexican Institute of Social Security.

AIM: To evaluate the progress of the Mexican Institute of Social Security Recovery Policy (IMSS-RP) in addressing the decline in essential health services caused by the COVID-19 pandemic. METHODS: We analyzed eleven indicators of essential health services from 35 IMSS state delegations. The assessment included ambulatory and hospital care indicators such as breast and cervical cancer screening, family medicine, dental and specialty visits, diabetes and hypertension visits and health outcomes, deliveries, and elective surgeries. We analyzed the period before (January 2018-March 2021) and during (April 2021-June 2023) the implementation of the IMSS-RP. Statistical analysis to determine the association of the policy with service indicators and the change in their trends included an interrupted time series analysis and Poisson Generalized Estimating Equation models. RESULTS: The volume of services showed substantial declines during the first year of the COVID-19 pandemic, reaching between 11 and 81% of pre-pandemic levels. All services increased significantly during the first 27 months of the IMSS-RP implementation; specialty visits, cervical and breast cancer screening, and diabetes control exceeded pre-pandemic levels (103%,112%,103%, and 138%, respectively). However, only deliveries and the percentage of patients with controlled diabetes and hypertension showed a stable increase following the IMSS-RP implementation, whereas the remaining services showed an initial increase but began to decrease over time. CONCLUSIONS: After 27 months of implementation, IMSS-RP achieved progress in increasing the volume of essential health services and improving chronic disease control. However, declining trends in several services signal the need to focalize the policy.

The cholera toxin B subunit induces trained immunity in dendritic cells and promotes CD8 T cell antitumor immunity.

Introduction: Innate immune training is a metabolic, functional, and epigenetic long-term reprogramming of innate cells triggered by different stimuli. This imprinting also reaches hematopoietic precursors in the bone marrow to sustain a memory-like phenotype. Dendritic cells (DCs) can exhibit memory-like responses, enhanced upon subsequent exposure to a pathogen; however, whether this imprinting is lineage and stimulus-restricted is still being determined. Nevertheless, the functional consequences of DCs training on the adaptive and protective immune response against non-infectious diseases remain unresolved. Methods: We evaluated the effect of the nontoxic cholera B subunit (CTB), LPS and LTA in the induction of trained immunity in murine DCs revealed by TNFa and LDH expression, through confocal microscopy. Additionally, we obtained bone marrow DCs (BMDCs) from mice treated with CTB, LPS, and LTA and evaluated training features in DCs and their antigen-presenting cell capability using multiparametric cytometry. Finally, we design an experimental melanoma mouse model to demonstrate protection induced by CTB-trained DCs in vivo. Results: CTB-trained DCs exhibit increased expression of TNFa, and metabolic reprogramming indicated by LDH expression. Moreover, CTB training has an imprint on DC precursors, increasing the number and antigen-presenting function in BMDCs. We found that training by CTB stimulates the recruitment of DC precursors and DCs infiltration at the skin and lymph nodes. Interestingly, training-induced by CTB promotes a highly co-stimulatory phenotype in tumor-infiltrating DCs (CD86+) and a heightened functionality of exhausted CD8 T cells (Ki67+, GZMB+), which were associated with a protective response against melanoma challenge in vivo. Conclusion: Our work indicates that CTB can induce innate immune training on DCs, which turns into an efficient adaptive immune response in the melanoma model and might be a potential immunotherapeutic approach for tumor growth control.

Outbreak of Fusarium solani Meningitis in Immunocompetent Persons Associated With Neuraxial Blockade in Durango, Mexico, 2022-2023.

Background: Fungal meningitis can be associated with epidural anesthesia procedures. Fusariosis is a rare infection typically affecting immunocompromised patients and rarely causes meningitis. During 2022-2023, public health officials responded to a large outbreak of Fusarium solani meningitis associated with epidural anesthesia in Durango, Mexico. Methods: The public health response and epidemiological and clinical features of patients affected by this outbreak were described. Coordinated actions were addressed to identify the etiological agent, determine its drug susceptibility, develop diagnostic tests, and implement clinical and epidemiological protocols. Retrospective analyses of clinical variables and outcomes were performed to determine association with better patient survival. Results: A total of 1801 persons exposed to epidural anesthesia were identified, of whom 80 developed meningitis. Fusarium solani was found in 3 brain biopsies and showed susceptibility to voriconazole and amphotericin B. After F solani polymerase chain reaction (PCR) implementation, 57 patients with meningitis were PCR-screened, and 31 (38.8%) had a positive result. Most patients were female (95%), and cesarean section was the most common surgical procedure (76.3%). The case fatality rate was 51.3% (41 patients) and the median hospitalization duration was 39.5 days (interquartile range, 18-86 days). Seventy-one patients (88.8%) received voriconazole/amphotericin B and 64 subjects (80%) additionally received steroids. Cox regression analysis showed an increased lethality risk in patients who received antifungal treatment after 5 days (hazard ratio, 2.1 [95% confidence interval, 1.01-4.48], P < .05). Conclusions: The F solani meningitis outbreak in Durango was an unprecedented medical challenge. Timely treatment and effective healthcare management were associated with better survival outcomes.

Potential biomarkers for fatal outcome prognosis in a cohort of hospitalized COVID-19 patients with pre-existing comorbidities.

The difficulty in predicting fatal outcomes in patients with coronavirus disease 2019 (COVID-19) impacts the general morbidity and mortality due to severe acute respiratory syndrome-coronavirus 2 infection, as it wears out the hospital services that care for these patients. Unfortunately, in several of the candidates for prognostic biomarkers proposed, the predictive power is compromised when patients have pre-existing comorbidities. A cohort of 147 patients hospitalized for severe COVID-19 was included in a descriptive, observational, single-center, and prospective study. Patients were recruited during the first COVID-19 pandemic wave (April-November 2020). Data were collected from the clinical history whereas immunophenotyping by multiparameter flow cytometry analysis allowed us to assess the expression of surface markers on peripheral leucocyte. Patients were grouped according to the outcome in survivors or non-survivors. The prognostic value of leucocyte, cytokines or HLA-DR, CD39, and CD73 was calculated. Hypertension and chronic renal failure but not obesity and diabetes were conditions more frequent among the deceased patient group. Mixed hypercytokinemia, including inflammatory (IL-6) and anti-inflammatory (IL-10) cytokines, was more evident in deceased patients. In the deceased patient group, lymphopenia with a higher neutrophil-lymphocyte ratio (NLR) value was present. HLA-DR expression and the percentage of CD39+ cells were higher than non-COVID-19 patients but remained similar despite the outcome. Receiver operating characteristic analysis and cutoff value of NLR (69.6%, 9.4), percentage NLR (pNLR; 71.1%, 13.6), and IL-6 (79.7%, 135.2 pg/mL). The expression of HLA-DR, CD39, and CD73, as many serum cytokines (other than IL-6) and chemokines levels do not show prognostic potential, were compared to NLR and pNLR values.

CXCR5 and TIM-3 expressions define distinct exhausted T cell subsets in experimental cutaneous infection with Leishmania mexicana.

T-cell exhaustion is a key stage in chronic infections since it limits immunopathology, but also hinders the elimination of pathogens. Exhausted T (Tex) cells encompass dynamic subsets, including progenitor cells that sustain long-term immunity through their memory/stem like properties, and terminally-differentiated cells, resembling the so-called Tex cells. The presence of Tex cells in chronic leishmaniasis has been reported in humans and murine models, yet their heterogeneity remains unexplored. Using flow cytometry, we identified Tex cells subtypes based on PD-1, CXCR5 and TIM-3 expressions in draining lymph nodes (dLNs) and lesion sites of C57BL/6 mice infected with L. mexicana at 30-, 60- and 90-days post-infection. We showed that infected mice developed a chronic infection characterized by non-healing lesions with a high parasite load and impaired Th1/Th2 cytokine production. Throughout the infection, PD-1+ cells were observed in dLNs, in addition to an enhanced expression of PD-1 in both CD4+ and CD8+ T lymphocytes. We demonstrated that CD4+ and CD8+ T cells were subdivided into PD-1+CXCR5+TIM-3- (CXCR5+), PD-1+CXCR5+TIM-3+ (CXCR5+TIM-3+), and PD-1+CXCR5-TIM-3+ (TIM-3+) subsets. CXCR5+ Tex cells were detected in dLNs during the whole course of the infection, whereas TIM-3+ cells were predominantly localized in the infection sites at day 90. CXCR5+TIM-3+ cells only increased at 30 and 60 days of infection in dLNs, whereas no increase was observed in the lesions. Phenotypic analysis revealed that CXCR5+ cells expressed significantly higher levels of CCR7 and lower levels of CX3CR1, PD-1, TIM-3, and CD39 compared to the TIM-3+ subset. CXCR5+TIM-3+ cells expressed the highest levels of all exhaustion-associated markers and of CX3CR1. In agreement with a less exhausted phenotype, the frequency of proliferating Ki-67 and IFN-γ expressing cells was significantly higher in the CXCR5+ subset within both CD4+ and CD8+ T cells compared to their respective TIM-3+ subsets, whereas CD8+CXCR5+TIM-3+ and CD8+TIM-3+ subsets showed an enhanced frequency of degranulating CD107a+ cells. In summary, we identified a novel, less-differentiated CXCR5+ Tex subset in experimental cutaneous leishmaniasis caused by L. mexicana. Targeting these cells through immune checkpoint inhibitors such as anti-PD-1 or anti PD-L1 might improve the current treatment for patients with the chronic forms of leishmaniasis.

Chronic Comorbidities in Middle Aged Patients Contribute to Ineffective Emergency Hematopoiesis in Covid-19 Fatal Outcomes.

BACKGROUND AND AIMS: Mexico is among the countries with the highest estimated excess mortality rates due to the COVID-19 pandemic, with more than half of reported deaths occurring in adults younger than 65 years old. Although this behavior is presumably influenced by the young demographics and the high prevalence of metabolic diseases, the underlying mechanisms have not been determined. METHODS: The age-stratified case fatality rate (CFR) was estimated in a prospective cohort with 245 hospitalized COVID-19 cases, followed through time, for the period October 2020-September 2021. Cellular and inflammatory parameters were exhaustively investigated in blood samples by laboratory test, multiparametric flow cytometry and multiplex immunoassays. RESULTS: The CFR was 35.51%, with 55.2% of deaths recorded in middle-aged adults. On admission, hematological cell differentiation, physiological stress and inflammation parameters, showed distinctive profiles of potential prognostic value in patients under 65 at 7 days follow-up. Pre-existing metabolic conditions were identified as risk factors of poor outcomes. Chronic kidney disease (CKD), as single comorbidity or in combination with diabetes, had the highest risk for COVID-19 fatality. Of note, fatal outcomes in middle-aged patients were marked from admission by an inflammatory landscape and emergency myeloid hematopoiesis at the expense of functional lymphoid innate cells for antiviral immunosurveillance, including NK and dendritic cell subsets. CONCLUSIONS: Comorbidities increased the development of imbalanced myeloid phenotype, rendering middle-aged individuals unable to effectively control SARS-CoV-2. A predictive signature of high-risk outcomes at day 7 of disease evolution as a tool for their early stratification in vulnerable populations is proposed.

Acral Melanoma Is Infiltrated with cDC1s and Functional Exhausted CD8 T Cells Similar to the Cutaneous Melanoma of Sun-Exposed Skin.

Acral melanoma (AM) is the most common melanoma in non-Caucasian populations, yet it remains largely understudied. As AM lacks the UV-radiation mutational signatures that characterize other cutaneous melanomas, it is considered devoid of immunogenicity and is rarely included in clinical trials assessing novel immunotherapeutic regimes aiming to recover the antitumor function of immune cells. We studied a Mexican cohort of melanoma patients from the Mexican Institute of Social Security (IMSS) (n = 38) and found an overrepresentation of AM (73.9%). We developed a multiparametric immunofluorescence technique coupled with a machine learning image analysis to evaluate the presence of conventional type 1 dendritic cells (cDC1) and CD8 T cells in the stroma of melanoma, two of the most relevant immune cell types for antitumor responses. We observed that both cell types infiltrate AM at similar and even higher levels than other cutaneous melanomas. Both melanoma types harbored programmed cell death protein 1 (PD-1+) CD8 T cells and PD-1 ligand (PD-L1+) cDC1s. Despite this, CD8 T cells appeared to preserve their effector function and expanding capacity as they expressed interferon-γ (IFN-γ) and KI-67. The density of cDC1s and CD8 T cells significantly decreased in advanced stage III and IV melanomas, supporting these cells' capacity to control tumor progression. These data also argue that AM could respond to anti-PD-1-PD-L1 immunotherapy.

Subclassification of B-acute lymphoblastic leukemia according to age, immunophenotype and microenvironment, predicts MRD risk in Mexican children from vulnerable regions.

Introduction: The decisive key to disease-free survival in B-cell precursor acute lymphoblastic leukemia in children, is the combination of diagnostic timeliness and treatment efficacy, guided by accurate patient risk stratification. Implementation of standardized and high-precision diagnostic/prognostic systems is particularly important in the most marginalized geographic areas in Mexico, where high numbers of the pediatric population resides and the highest relapse and early death rates due to acute leukemias are recorded even in those cases diagnosed as standard risk. Methods: By using a multidimensional and integrated analysis of the immunophenotype of leukemic cells, the immunological context and the tumor microenvironment, this study aim to capture the snapshot of acute leukemia at disease debut of a cohort of Mexican children from vulnerable regions in Puebla, Oaxaca and Tlaxcala and its potential use in risk stratification. Results and discussion: Our findings highlight the existence of a distinct profile of ProB-ALL in children older than 10 years, which is associated with a six-fold increase in the risk of developing measurable residual disease (MRD). Along with the absence of CD34+ seminal cells for normal hematopoiesis, this ProB-ALL subtype exhibited several characteristics related to poor prognosis, including the high expression level of myeloid lineage markers such as MPO and CD33, as well as upregulation of CD19, CD34, CD24, CD20 and nuTdT. In contrast, it showed a trend towards decreased expression of CD9, CD81, CD123, CD13, CD15 and CD21. Of note, the mesenchymal stromal cell compartment constituting their leukemic niche in the bone marrow, displayed characteristics of potential suppressive microenvironment, such as the expression of Gal9 and IDO1, and the absence of the chemokine CXCL11. Accordingly, adaptive immunity components were poorly represented. Taken together, our results suggest, for the first time, that a biologically distinct subtype of ProB-ALL emerges in vulnerable adolescents, with a high risk of developing MRD. Rigorous research on potential enhancing factors, environmental or lifestyle, is crucial for its detection and prevention. The use of the reported profile for early risk stratification is suggested.

Immunotherapy Options for Acral Melanoma, A fast-growing but Neglected Malignancy.

Melanoma is the deadliest form of skin cancer. It is classified as cutaneous and non-cutaneous, with the former characterized by developing in sun-exposed areas of the skin, UV-light radiation being its most important risk factor and ordinarily affecting fair skin populations. In recent years, the incidence of melanoma has been increasing in populations with darker complexion, for example, Hispanics, in which acral melanoma is highly prevalent. The WHO estimates that the incidence and mortality of melanoma will increase by more than 60% by 2040, particularly in low/medium income countries. Acral melanoma appears in the palms, soles and nails, and because of these occult locations, it is often considered different from other cutaneous melanomas even though it also originates in the skin. Acral melanoma is very rare in Caucasian populations and is often not included from genetic analysis and clinical trials. In this review, we present the worldwide epidemiology of acral melanoma; we summarize its genetic characterization and point out important signaling pathways for targeted therapy. We also discuss how genetic analyses have shown that acral melanoma carries a sufficient mutational load and neoantigen formation to be targeted by the immune system, arguing for a potential benefit with novel immunotherapeutic strategies, alone or combined with targeted therapy. This is important because chemotherapy remains the first-line treatment in non-developed nations despite a disheartening response. In summary, the increased incidence and mortality of acral melanoma in low/medium income countries calls for increasing our knowledge about its nature and therapeutic options and leveling off the asymmetric research conducted primarily on Caucasian populations.

A Machine Learning Workflow of Multiplexed Immunofluorescence Images to Interrogate Activator and Tolerogenic Profiles of Conventional Type 1 Dendritic Cells Infiltrating Melanomas of Disease-Free and Metastatic Patients.

Melanoma is the deadliest form of skin cancer. Due to its high mutation rates, melanoma is a convenient model to study antitumor immune responses. Dendritic cells (DCs) play a key role in activating cytotoxic CD8+ T lymphocytes and directing them to kill tumor cells. Although there is evidence that DCs infiltrate melanomas, information about the profile of these cells, their activity states, and potential antitumor function remains unclear, particularly for conventional DCs type 1 (cDC1). Approaches to profiling tumor-infiltrating DCs are hindered by their diversity and the high number of signals that can affect their state of activation. Multiplexed immunofluorescence (mIF) allows the simultaneous analysis of multiple markers, but image-based analysis is time-consuming and often inconsistent among analysts. In this work, we evaluated several machine learning (ML) algorithms and established a workflow of nine-parameter image analysis that allowed us to study cDC1s in a reproducible and accessible manner. Using this workflow, we compared melanoma samples between disease-free and metastatic patients at diagnosis. We observed that cDC1s are more abundant in the tumor infiltrate of the former. Furthermore, cDC1s in disease-free patients exhibit an expression profile more congruent with an activator function: CD40highPD-L1low CD86+IL-12+. Although disease-free patients were also enriched with CD40-PD-L1+ cDC1s, these cells were also more compatible with an activator phenotype. The opposite was true for metastatic patients at diagnosis who were enriched for cDC1s with a more tolerogenic phenotype (CD40lowPD-L1highCD86-IL-12-IDO+). ML-based workflows like the one developed here can be used to analyze complex phenotypes of other immune cells and can be brought to laboratories with standard expertise and computer capacity.

The Protective Role of pVHL in Imiquimod-Induced Psoriasis-like Skin Inflammation.

Psoriasis is a chronic inflammatory disease distinguished by an excessive proliferation and abnormal differentiation of keratinocytes. Immune cells, such as T lymphocytes and neutrophils, and inflammatory cytokines, such as Tumor Necrosis Factor-α (TNF-α) and interleukin 17 (IL-17), are essential for maintaining psoriatic lesions. Additionally, a hypoxic milieu present in the skin promotes the expression of transcriptional factor hypoxia-inducible factor-1 alpha (HIF-1α). This protein regulates the expression of angiogenic and glycolytic factors, such as vascular endothelial grown factor and lactate dehydrogenase (LDH), both relevant in chronic inflammation. The von Hippel-Lindau protein (pVHL) is a negative regulator of HIF-1α. Previously, we found that pVHL was almost absent in the lesions of psoriasis patients; therefore, we investigated the impact of rescue pVHL expression in lesional skin. We used the imiquimod-induced psoriasis-like mouse model as an adenoviral vector that allowed us to express pVHL in the skin. Our data show that, in lesional skin, pVHL expression was reduced, whereas HIF-1α was increased. Remarkably, the retrieval of pVHL prevented psoriatic lesions, diminishing erythema, scale, and epidermal and vascular thickness. Furthermore, pVHL expression was capable of reducing HIF-1α, LDH, TNF-α and immune cell infiltration (mainly IL-17+ neutrophils). In conclusion, our results demonstrate that pVHL has a protective role to play in the pathophysiology of psoriasis.

Antigen Targeting of Porcine Skin DEC205+ Dendritic Cells.

Dendritic cell (DC) targeting by DEC205+ cells effectively promotes the internalization of antigens that may trigger a specific immune response. In this study, we evaluated the ability of a recombinant antibody, anti-DEC205 (rAb ZH9F7), to trigger cellular endocytosis in subpopulations of DCs and targeted cells after intradermal injection and subsequent migration toward lymph nodes. Furthermore, the cellular immune response was evaluated in pigs after intradermal application of the antigenized rAb ZH9F7 combined with porcine circovirus type 2 cap antigen (rAb ZH9F7-Cap). We demonstrated that rAb ZH9F7 recognized conventional type 1 and 2 DCs from the blood and skin and monocytes. It promoted receptor-mediated endocytosis and migration of cDCs and moDCs toward regional lymph nodes. Intradermal application of rAb ZH9F7-Cap induced a higher frequency of IFN-γ-secreting CD4+CD8+ T lymphocytes and antibodies against Cap protein than that in the control group. In conclusion, the rAb ZH9F7-Cap system promoted the target of skin cDC1 and cDC2, provoking migration to the regional lymph nodes and inducing a Th1 response, as evidenced by the proliferation of double-positive CD4+CD8+ T cells, which correlates with an enhanced ability to target the cDC1 subset both in vitro and in vivo.

NLRP3 Regulates IL-4 Expression in TOX+ CD4+ T Cells of Cutaneous T Cell Lymphoma to Potentially Promote Disease Progression.

In cutaneous T cell lymphoma (CTCL), a dominant Th2 profile associated with disease progression has been proposed. Moreover, although the production and regulation of IL-4 expression during the early stages of the disease may have important implications in later stages, these processes are poorly understood. Here, we demonstrate the presence of TOX+ CD4+ T cells that produce IL-4+ in early-stage skin lesions of CTCL patients and reveal a complex mechanism by which the NLRP3 receptor promotes a Th2 response by controlling IL-4 production. Unassembled NLRP3 is able to translocate to the nucleus of malignant CD4+ T cells, where it binds to the human il-4 promoter. Accordingly, IL-4 expression is decreased by knocking down and increased by promoting the nuclear localization of NLRP3. We describe a positive feedback loop in which IL-4 inhibits NLRP3 inflammasome assembly, thereby further increasing its production. IL-4 induced a potentially malignant phenotype measured based on TOX expression and proliferation. This mechanism of IL-4 regulation mediated by NLRP3 is amplified in late-stage CTCL associated with disease progression. These results indicate that NLRP3 might be a key regulator of IL-4 expression in TOX+ CD4+ T cells of CTCL patients and that this mechanism might have important implications in the progression of the disease.

CD4+ and CD8+ Circulating Memory T Cells Are Crucial in the Protection Induced by Vaccination with Salmonella Typhi Porins.

Salmonella enterica serovar Typhi (S. Typhi) porins, OmpC and OmpF, are potent inducers of the immune response against S. Typhi in mice and humans. Vaccination with porins induces the protection against 500 LD50 of S. Typhi, life-lasting bactericidal antibodies and effector T cell responses in mice; however, the nature of the memory T cell compartment and its contribution to protection remains unknown. In this work, we firstly observed that vaccination with porins induces in situ (skin) CD4+ and CD8+ T cell responses. Analysis of the porin-specific functional responses of skin CD4+ and CD8+ T cells showed IFN-gamma- and IL-17-producing cells in both T cell populations. The memory phenotype of porin-specific T cells indicated the presence of resident and effector memory phenotypes in the skin, and a central memory phenotype in the skin-draining lymph node. In addition, we demonstrated that vaccination with porins via skin reduces the bacterial burden following challenge. Finally, evaluating the role of the circulating T cell memory population in protection, we showed that circulating memory CD4+ and CD8+ T cells are crucial in porin-mediated protection against S. Typhi. Overall, this study highlights the importance of inducing circulating memory T cell responses in order to achieve the optimal protection provided by porins, showing a mechanism that could be sought in the rational development of vaccines.

Induction of Therapeutic Protection in an HPV16-Associated Mouse Tumor Model Through Targeting the Human Papillomavirus-16 E5 Protein to Dendritic Cells.

HPV E5 is an oncoprotein mainly expressed in premalignant lesions, which makes it an important target for a vaccine to prevent or cure cervical cancer (CC). In this study, we evaluated whether E5 targeted to DEC-205, present in dendritic cells (DCs), could induce a therapeutic protection against HPV16-induced tumor cells in a mouse model. The HPV-16 E5 (16E5) protein was cross-linked to a monoclonal antibody (mAb) specific to mouse DEC-205 (anti-DEC-205:16E5) or to an isotype control mAb (isotype:16E5). Rotavirus VP6 was cross-linked to the mouse anti-DEC-205 mAb (anti-DEC-205:VP6) as a non-specific antigen control. BALB/c mice were inoculated subcutaneously (s.c.) with the 16E5-expressing BMK-16/myc tumor cells, and 7 and 14 days later the mice were immunized s.c. with the conjugates, free 16E5 or PBS in the presence of adjuvant. Tumor growth was monitored to evaluate protection. A strong protective immune response against the tumor cells was induced when the mice were inoculated with the anti-DEC-205:16E5 conjugate, since 70% of the mice controlled the tumor growth and survived, whereas the remaining 30% developed tumors and died by day 72. In contrast, 100% of the mice in the control groups died by day 30. The anti-DEC-205:16E5 conjugate was found to induce 16E5-specific memory T cells, with a Th1/Th17 profile. Both CD4+ and CD8+ T cells contributed to the observed protection. Finally, treating mice that had developed tumors with an anti-PD-1 mAb, delayed the tumor growth for more than 20 days. These results show that targeting 16E5 to DEC-205, alone or combined with an immune checkpoint blockade, could be a promising protocol for the treatment of the early stages of HPV-associated cancer.

Induction of Progenitor Exhausted Tissue-Resident Memory CD8+ T Cells Upon Salmonella Typhi Porins Adjuvant Immunization Correlates With Melanoma Control and Anti-PD-1 Immunotherapy Cooperation.

Immunotherapy has improved the clinical response in melanoma patients, although a relevant percentage of patients still cannot be salvaged. The search for the immune populations that provide the best tumor control and that can be coaxed by immunotherapy strategies is a hot topic in cancer research nowadays. Tumor-infiltrating TCF-1+ progenitor exhausted CD8+ T cells seem to grant the best melanoma prognosis and also efficiently respond to anti-PD-1 immunotherapy, giving rise to a TIM-3+ terminally exhausted population with heightened effector activity. We tested Porins from Salmonella Typhi as a pathogen associated molecular pattern adjuvant of natural or model antigen in prophylactic and therapeutic immunization approaches against murine melanoma. Porins induced protection against melanomas, even upon re-challenging of tumor-free mice. Porins efficiently expanded IFN-γ-producing CD8+ T cells and induced central and effector memory in lymph nodes and tissue-resident (Trm) T cells in the skin and tumors. Porins induced TCF-1+ PD-1+ CD8+ Trm T cells in the tumor stroma and the presence of this population correlated with melanoma growth protection in mice. Porins immunization also cooperated with anti-PD-1 immunotherapy to hamper melanoma growth. Importantly, the potentially protective Trm populations induced by Porins in the murine model were also observed in melanoma patients in which their presence also correlated with disease control. Our data support the use of cancer vaccination to sculpt the tumor stroma with efficient and lasting Trm T cells with effector activities, highlighting the use of Porins as an adjuvant. Furthermore, our data place CD8+ Trm T cells with a progenitor exhausted phenotype as an important population for melanoma control, either independently or in cooperation with anti-PD-1 immunotherapy.

SARS-CoV-2: previous coronaviruses, immune response, and development of vaccines.

Since the emergence of the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China at the end of 2019, when its characteristics were practically unknown, one aspect was evident: its high contagion rate. This high infection rate resulted in the spread of the virus in China, Europe, and, eventually, the rest of the world, including Mexico. At present, around 9 million people are infected, and around 470,000 have died worldwide. In this context, the need to generate protective immunity, and especially the generation of a vaccine that can protect the world population against infection in the shortest possible time, is a challenge that is being addressed in different countries using different strategies in multiple clinical trials. This opinion article will present the evidence of the induction of immune response in some of the viruses of the coronavirus family before COVID-19, such as SARS-CoV and MERS-CoV (Middle East respiratory syndrome coronavirus). The information collected about the induction of an immune response by SARS-CoV-2 will be presented, as well as a description of the vaccine candidates reported to date in the various ongoing clinical trials. Finally, an opinion based on the evidence presented will be issued on the potential success of developing vaccine prototypes.

Desde el surgimiento del nuevo coronavirus SARS-CoV-2 (coronavirus tipo 2 del síndrome respiratorio agudo severo) en China a finales del año 2019, cuando todavía era desconocido prácticamente en todos los aspectos, una característica era evidente: el alto índice de contagio entre la población. Esto resultó en la expansión del virus en China, Europa y, finalmente, en el resto del mundo, incluyendo México. Actualmente, alrededor de 9 millones de personas están infectadas, y han muerto cerca de 500,000 en todo el mundo. En este contexto, la necesidad de generar inmunidad protectora y, sobre todo, el desarrollo de una vacuna que pueda proteger a la población mundial contra la infección en el menor tiempo posible, es un reto que se está abordando en distintos países utilizando diversas estrategias en múltiples ensayos clínicos. En este artículo de opinión se presentan las evidencias de la inducción de respuesta inmunitaria con algunos de los virus de la familia de coronavirus previos al SARS-CoV-2, como el SARS-CoV (coronavirus del síndrome respiratorio agudo severo) y el MERS-CoV (síndrome respiratorio por coronavirus de Oriente Medio). Además, se presenta lo reportado hasta el momento acerca de la inducción de respuesta inmunitaria por el SARS-CoV-2, así como una descripción de los candidatos a vacunas informados hasta el momento en los distintos ensayos clínicos en curso. Finalmente se emite una opinión, basada en las evidencias presentadas, acerca del éxito potencial de los prototipos de vacunas en desarrollo.

SARS-CoV-2: previous coronaviruses, immune response, and development of vaccines / SARS-CoV-2: coronavirus previos, respuesta inmune y desarrollo de vacunas

Abstract Since the emergence of the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China at the end of 2019, when its characteristics were practically unknown, one aspect was evident: its high contagion rate. This high infection rate resulted in the spread of the virus in China, Europe, and, eventually, the rest of the world, including Mexico. At present, around 9 million people are infected, and around 470,000 have died worldwide. In this context, the need to generate protective immunity, and especially the generation of a vaccine that can protect the world population against infection in the shortest possible time, is a challenge that is being addressed in different countries using different strategies in multiple clinical trials. This opinion article will present the evidence of the induction of immune response in some of the viruses of the coronavirus family before COVID-19, such as SARS-CoV and MERS-CoV (Middle East respiratory syndrome coronavirus). The information collected about the induction of an immune response by SARS-CoV-2 will be presented, as well as a description of the vaccine candidates reported to date in the various ongoing clinical trials. Finally, an opinion based on the evidence presented will be issued on the potential success of developing vaccine prototypes.

Resumen Desde el surgimiento del nuevo coronavirus SARS-CoV-2 (coronavirus tipo 2 del síndrome respiratorio agudo severo) en China a finales del año 2019, cuando todavía era desconocido prácticamente en todos los aspectos, una característica era evidente: el alto índice de contagio entre la población. Esto resultó en la expansión del virus en China, Europa y, finalmente, en el resto del mundo, incluyendo México. Actualmente, alrededor de 9 millones de personas están infectadas, y han muerto cerca de 500,000 en todo el mundo. En este contexto, la necesidad de generar inmunidad protectora y, sobre todo, el desarrollo de una vacuna que pueda proteger a la población mundial contra la infección en el menor tiempo posible, es un reto que se está abordando en distintos países utilizando diversas estrategias en múltiples ensayos clínicos. En este artículo de opinión se presentan las evidencias de la inducción de respuesta inmunitaria con algunos de los virus de la familia de coronavirus previos al SARS-CoV-2, como el SARS-CoV (coronavirus del síndrome respiratorio agudo severo) y el MERS-CoV (síndrome respiratorio por coronavirus de Oriente Medio). Además, se presenta lo reportado hasta el momento acerca de la inducción de respuesta inmunitaria por el SARS-CoV-2, así como una descripción de los candidatos a vacunas informados hasta el momento en los distintos ensayos clínicos en curso. Finalmente se emite una opinión, basada en las evidencias presentadas, acerca del éxito potencial de los prototipos de vacunas en desarrollo.

Interferon-gamma-activated macrophages infected with Burkholderia cenocepacia process and present bacterial antigens to T-cells by class I and II major histocompatibility complex molecules.

Burkholderia cenocepacia is an emerging opportunistic pathogen for people with cystic fibrosis and chronic granulomatous disease. Intracellular survival in macrophages within a membrane-bound vacuole (BcCV) that delays acidification and maturation into lysosomes is a hallmark of B. cenocepacia infection. Intracellular B. cenocepacia induce an inflammatory response leading to macrophage cell death by pyroptosis through the secretion of a bacterial deamidase that results in the activation of the pyrin inflammasome. However, how or whether infected macrophages can process and present B. cenocepacia antigens to activate T-cells has not been explored. Engulfed bacterial protein antigens are cleaved into small peptides in the late endosomal major histocompatibility class II complex (MHC) compartment (MIIC). Here, we demonstrate that BcCVs and MIICs have overlapping features and that interferon-gamma-activated macrophages infected with B. cenocepacia can process bacterial antigens for presentation by class II MHC molecules to CD4+ T-cells and by class I MHC molecules to CD8+ T-cells. Infected macrophages also release processed bacterial peptides into the extracellular medium, stabilizing empty class I MHC molecules of bystander cells. Together, we conclude that BcCVs acquire MIIC characteristics, supporting the notion that macrophages infected with B. cenocepacia contribute to establishing an adaptive immune response against the pathogen.