Emergencia de variante Delta- B. 1.617.2: su impacto potencial en la evolución de la pandemia por SARS-CoV-2 / Delta-B. 1.617.2 variant emergency:: its potential impact on the evolution of the SARS-CoV-2 pandemic

Se describe hasta la fecha de hoy, 4 de julio del 2021, la evidencia existente sobre la variante Delta del SARS-CoV-2, su impacto en la trasmisión, en la severidad de la infección y su probable evasión a la respuesta inmune. (AU)

As of today, July 4, 2021, the existing evidence on the Delta variant of SARS-CoV-2, its impact on transmission, on the severity of the infection and its probable evasion of the immune response is described. (AU)

Tumor microenvironment and immune evasion in head and neck squamous cell carcinoma / 国际口腔科学杂志·英文版

Head and neck squamous cell carcinoma (HNSCC), an aggressive malignancy, is characterized by high morbidity and low survival rates with limited therapeutic options outside of regional surgery, conventional cytotoxic chemotherapy, and irradiation. Increasing studies have supported the synergistic role of the tumor microenvironment (TME) in cancer advancement. The immune system, in particular, plays a key role in surveillance against the initiation, development, and progression of HNSCC. The understanding of how neoplastic cells evolve and evade the immune system whether through self-immunogenicity manipulation, or expression of immunosuppressive mediators, provides the foundation for the development of advanced therapies. Furthermore, the crosstalk between cancer cells and the host immune system have a detrimental effect on the TME promoting angiogenesis, proliferation, and metastasis. This review provides a recent insight into the role of the key inflammatory cells infiltrating the TME, with a focus on reviewing immunological principles related to HNSCC, as cancer immunosurveillance and immune escape, including a brief overview of current immunotherapeutic strategies and ongoing clinical trials.

Structural and physiological changes of the human body upon SARS-CoV-2 infection / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Since December 2019, the novel coronavirus (severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)) has spread to many countries around the world, developing into a global pandemic with increasing numbers of deaths reported worldwide. To data, although some vaccines have been developed, there are no ideal drugs to treat novel coronavirus pneumonia (coronavirus disease 2019 (COVID-19)). By examining the structure of the coronavirus and briefly describing its possible pathogenesis based on recent autopsy reports conducted by various teams worldwide, this review analyzes the possible structural and functional changes of the human body upon infection with SARS-CoV-2. We observed that the most prominent pathological changes in COVID-19 patients are diffuse alveolar damage (DAD) of the lungs and microthrombus formation, resulting in an imbalance of the ventilation/perfusion ratio and respiratory failure. Although direct evidence of viral infection can also be found in other organs and tissues, the viral load is relatively small. The conclusion that the injuries of the extra-pulmonary organs are directly caused by the virus needs further investigation.

Yin-Yang-1 decreases Fas-induced apoptosis in acute lymphoblastic leukemia under hypoxic conditions: its implications in immune evasion / YY1 induce la disminución de la apoptosis a través de Fas en la leucemia linfoblástica aguda en condiciones hipóxicas: implicaciones en la evasión de la respuesta inmunitaria

Abstract Background: Acute lymphoblastic leukemia (ALL) is an aggressive malignant disease with high prevalence in pediatric patients. It has been shown that the downregulation of Fas expression is correlated with an inadequate response in ALL, although these mechanisms are still not well understood. Several reports demonstrated that hypoxia is involved in dysfunctional apoptosis. Yin-Yang-1 (YY1) transcription factor is involved in resistance to apoptosis, tumor progression, and it is increased in different types of cancer, including leukemia. The regulatory mechanism underlying YY1 expression in leukemia is still not understood, but it is known that YY1 negatively regulates Fas expression. The study aimed to evaluate the effect of YY1 on Fas expression under hypoxic conditions in ALL. Methods: Leukemia cell line RS4; 11 was cultured under normoxic and hypoxic conditions. YY1, Fas receptor, and hypoxia-inducible factor (HIF-1α) expression were analyzed. After treatment with a Fas agonist (DX2), apoptosis was analyzed through the detection of active caspase 3. Data were analyzed using Pearson’s correlation. Results: Leukemia cells co-expressed both HIF-1α and YY1 under hypoxia, which correlated with a downregulation of Fas expression. During hypoxia, the levels of apoptosis diminished after DX2 treatment. The analysis revealed that patients with high levels of HIF-1α also express high levels of YY1 and low levels of Fas. Conclusions: These results suggest that YY1 negatively regulates the expression of the Fas receptor, which could be involved in the escape of leukemic cells from the immune response contributing to the ALL pathogenesis.

Resumen Introducción: La leucemia linfoblástica aguda (LLA) es una enfermedad con alta prevalencia en la población pediátrica. El mecanismo por el cual el receptor de Fas participa en la regulación inmunitaria en los tumores es desconocido, pero se sabe que está subexpresado en LLA. El factor de transcripción Ying-Yang-1 (YY1) está involucrado en la resistencia a la apoptosis y la progresión tumoral; se encuentra aumentado en diferentes tumores, incluida la LLA. Aunque los mecanismos que regulan la expresión de YY1 en LLA son desconocidos, se sabe que YY1 regula la expresión del receptor de Fas. El objetivo de este trabajo fue evaluar el efecto de YY1 en la expresión de Fas en condiciones de hipoxia en la LLA. Métodos: Se cultivaron células RS4;11 en condiciones de hipoxia y se analizó la expresión de YY1, receptor de Fas y HIF-1α. La apoptosis fue inducida usando un agonista de Fas (DX2) y se analizó con la detección de caspasa 3 activa. Los datos se analizaron mediante correlación de Pearson. Resultados: Las células RS4;11 coexpresaron HIF-1αy YY1 en hipoxia, lo cual correlaciona con una baja expresión de Fas. La apoptosis se encontró disminuida durante condiciones de hipoxia, después del tratamiento con DX2. El análisis bioinformático mostró que los pacientes con altos niveles de HIF-1αpresentan YY1 elevado y bajos niveles del receptor de Fas. Conclusiones: Estos resultados sugieren que YY1 regula negativamente la expresión del receptor de Fas, lo cual podría estar involucrado en el escape de las células leucémicas a la respuesta inmunitaria, contribuyendo a la patogénesis de la LLA.

Genómica de rotavirus. Impacto en salud pública / Rotavirus genomics. Public health impact

Resumen: Con la introducción de las vacunas de rotavirus Rotarix (RV1) o RotaTeq (RV5) en programas nacionales de vacunación de diversos países, surgió la preocupación de que la presión inmune generada condujera al aumento en la prevalencia de genotipos virales no incluidos en las vacunas, o bien del surgimiento de nuevas cepas que pudieran escapar a la respuesta inmune protectora inducida por la vacunación. La variación natural de los rotavirus ha hecho que sea muy difícil distinguir si el cambio en las cepas circulantes se debe a la presión selectiva impuesta por las vacunas o bien a la fluctuación natural de las cepas. Si acaso ha habido una presión selectiva, ésta ha sido hasta ahora baja. Sin embargo, es importante mantener la vigilancia epidemiólogica y poner atención al surgimiento de cepas resistentes a la inmunidad, en particular en países en desarrollo en los que se ha descrito una mayor diversidad viral.

Abstract: With the introduction of rotavirus vaccines Rotarix (RV1) or RotaTeq (RV5) in the immunization programs of an increasing number of countries, there is concern that the immune selection pressure induced will cause an increase in the prevalence of virus genotypes not included in the vaccine formulation, or to the appearance of novel rotavirus strains that could evade the protective immune response. The natural fluctuation of rotaviruses makes it difficult to distinguish if the change in the circulating strains is due to the vaccine selective pressure or to the natural diversity fluctuation of viruses. If there has been a selective pressure, it has been low so far. However, it is important to keep an epidemiological surveillance and pay attention to the emergence of strains that are resistant to the vaccine, in particular in those countries where the viral diversity has been shown to be higher.

Expression of NLRP3 inflammasome in leprosy indicates immune evasion of Mycobacterium leprae

BACKGROUND Leprosy is an infectious-contagious disease caused by Mycobacterium leprae that remain endemic in 105 countries. This neglected disease has a wide range of clinical and histopathological manifestations that are related to the host inflammatory and immune responses. More recently, the inflammasome has assumed a relevant role in the inflammatory response against microbiological agents. However, the involvement of inflammasome in leprosy remains poorly understood. OBJECTIVES The aim is to associate biomarkers of inflammasome with the different immunopathological forms of leprosy. METHODS We performed an observational, cross-sectional, and comparative study of the immunophenotypic expression of inflammasome-associated proteins in immunopathological forms of leprosy of 99 skin lesion samples by immunohistochemistry. The intensity and percentage of NLRP3, Caspase-1, Caspases-4/5, interleukin-1β and interleukin-18 immunoreactivities in the inflammatory infiltrate of skin biopsies were evaluated. FINDINGS Strong expression of NLRP3 and inflammatory Caspases-4/5 were observed in lepromatous leprosy (lepromatous pole). In addition, were observed low expression of caspase-1, interleukin-1β, and interleukin-18 in tuberculoid and lepromatous leprosy. The interpolar or borderline form showed immunophenotype predominantly similar to the lepromatous pole. MAIN CONCLUSIONS Our results demonstrate that the NLRP3 inflammasome is inactive in leprosy, suggesting immune evasion of M. leprae.

Mechanism of Anti Apoptosis and Immune Evasion in Drug-Resistant Leukemia Cells Mediated by STAT3 / 中国实验血液学杂志

OBJECTIVE@#To investigate the mechanisms of anti-apoptosis and immune evasion in drug-resistant leukemia cells mediated by STAT3, further to explore the possible mechanism of leukemia relapse caused by minimal residual.@*METHODS@#Drug-resistance leukemia cell line was established by transfecting pcDNA3.1-STAT3 into K562 cells (K562/STAT3). The expression of STAT3, BAX and NKG2D ligands (MICA and ULBP1) in K562/-cells, K562/STAT3 were detected by Western blot and/or RQ-PCR. Cells apoptosis and the killing effect of NK cells on leukemia cells were detected by flow cytometry.@*RESULTS@#The expression of the total STAT3, STAT3 phosphorylation in K562/STAT3 was significantly increased, and P-gp mRNA expression was increased also significantly (P<0.005). In K562/STAT3 cells, the expression of pro-apoptotic BAX (P=0.005) was significantly lower, and the number of apoptotic cells (P=0.002) induced by adriamycin was significantly decreased as compared with those in K562/- cells. After K562/STAT3 cells were treated by STAT3 inhibitor (SH-4-54), the expression of BAX mRNA (P=0.017) was significantly higher and the number of apoptotic cells (P=0.005) was significantly increased. The MICA and ULBP1 mRNA expression in K562/STAT3 cells was significantly lower than that in K562/- cells, and also for MICA and ULBP1 protein (MICA and ULPB1 mRNA: P<0.0001, MICA protein: P=0.001, ULPB1 protein: P=0.022). After K562/STAT3 cells were treated with STAT3 inhibitor (SH-4-54), the expression of MICA mRNA and protein was increased (mRNA: P=0.001, protein: P=0.002), but ULBP1 mRNA and protein showed no significantly change (mRNA: P=0.137, protein: P=0.1905). The cytotoxicity of NK cells to K562/STAT3 cells was susceptible as compared with K562/- (P=0.002), but the cytotoxicity of K562/STAT3 cells to NK cell could be recovered by STAT3 inhibitor (P=0.006).@*CONCLUSION@#STAT3 phosphorylation can inhibits cell apoptosis and promotes cell immune escape. STAT3 inhibitors can promote the apoptosis of leukemia cells and increase their sensitivity to NK cells.

Loss of Human Leukocyte Antigen Class I Expression Is Associated with Poor Prognosis in Patients with Advanced Breast Cancer

BACKGROUND: Human leukocyte antigen class I (HLA-I) molecules play important roles in regulating immune responses. Loss or reduction of HLA-I expression has been shown to be associated with prognosis in several cancers. Regulatory T-cells (Tregs) also play critical functions in immune response regulation. Evaluation of HLA-I expression status by the EMR8-5 antibody and its clinical impact in breast cancer have not been well studied, and its relationship with Tregs remains unclear. METHODS: We evaluated HLA-I expression and Treg infiltration by immunohistochemistry in 465 surgically resected breast cancer samples. We examined the correlation between HLA-I expression and Treg infiltration and clinicopathologic characteristics and survival analyses were performed. RESULTS: Total loss of HLA-I expression was found in 84 breast cancer samples (18.1%). Univariate survival analysis revealed that loss of HLA-I expression was significantly associated with worse disease-specific survival (DSS) (p = .029). HLA-I was not an independent prognostic factor in the entire patient group, but it was an adverse independent prognostic factor for DSS in patients with advanced disease (stage II–IV) (p = .031). Treg numbers were significantly higher in the intratumoral stroma of HLA-I–positive tumors than in HLA-I–negative tumors (median 6.3 cells/high power field vs 2.1 cells/high power field, p < .001). However, Tregs were not an independent prognostic factor in our cohort. CONCLUSIONS: Our findings suggest that the loss of HLA-I expression is associated with poor prognosis in breast cancer patients, highlighting the role of HLA-I alterations in immune evasion mechanisms of breast cancer. HLA-I could be a promising marker that enables the application of more effective and precise immunotherapies for patients with advanced breast cancer.

Role of Immunosuppressive Microenvironment in Acquiring Immunotolerance Post-Photothermal Therapy

BACKGROUND: Nanoparticle-mediated photothermal therapy (PTT) has been well studied as a treatment for cancer. However, the therapeutic outcome of PTT is often hindered by the penetration depth of laser light. In the tumor margin beyond the laser penetration limit, tumor recurrence often occurs, bypassing the immune response of the host. Accumulating evidence suggests the prominent role of tumor microenvironment (TME) and its interactions with the immune components contribute to an immunosuppressive milieu during the post-therapy period. Here, we explored the immunosuppressive cascade generated after PTT, which is responsible for tumor recurrence, and identified the potential targets to achieve an effective PTT period. METHODS: Here, we investigated the immunosuppressive cascade generated after PTT in a CT26 tumor bearing mouse. The liposomal system loaded with the indocyanine green (ICG) was utilized for the generation of PTT with high efficiency. Immunological factors such as cytokines and protein expressions post-therapy were investigated through enzyme-linked immunosorbent assay, flow cytometry and western blot analysis. RESULTS: Our results suggested that PTT with ICG-loaded liposomes (Lipo-ICG) was effective for the first 5 days after treatment, resulting in tumor suppression. However, an immunosuppressive and pro-inflammatory environment developed thereafter, causing the recruitment and upregulation of the immune evasion factors of heat shock protein 70, programmed death ligand 1, indoleamine-dioxygenase, interleukin-6, transforming growth factor-β, regulatory T-cells, and myeloid-derived suppressor cells, to develop immunotolerance. CONCLUSION: Collectively, these findings have determined potential therapeutic targets to modulate the TME during PTT and achieve tumor ablation without remission.

Adenosine Blockage in Tumor Microenvironment and Improvement of Cancer Immunotherapy

Immunotherapy has been introduced into cancer treatment methods, but different problems have restricted the efficacy of these protocols in clinical trials such as the presence of various immunomodulatory factors in the tumor microenvironment. Adenosine is an immunosuppressive metabolite produced by the tumor to promote growth, invasion, metastasis, and immune evasion. Many studies about adenosine and its metabolism in cancer have heightened interest in pursuing this treatment approach. It seems that targeting the adenosine pathway in combination with immunotherapy may lead to efficient antitumor response. In this review, we provide information on the roles of both adenosine and CD73 in the immune system and tumor development. We also describe recent studies about combination therapy with both purinergic inhibitors and other immunotherapeutic methods.

miR-195/miR-497 Regulate CD274 Expression of Immune Regulatory Ligands in Triple-Negative Breast Cancer / 한국유방암학회지

PURPOSE: Immune suppression is common in patients with advanced breast cancer but the mechanisms underlying this phenomenon have not been sufficiently studied. In this study, we aimed to identify B7 family members that were able to predict the immune status of patients, and which may serve as potential targets for the treatment of breast cancer. We also aimed to identify microRNAs that may regulate the expression of B7 family members. METHODS: The Cancer Genome Atlas data from 1,092 patients with breast cancer, including gene expression, microRNA expression and survival data, were used for statistical and survival analyses. Polymerase chain reaction and Western blot were used to measure messenger RNA and protein expression, respectively. Luciferase assay was used to investigate direct microRNA target. RESULTS: Bioinformatic analysis predicted that microRNA (miR)-93, miR-195, miR-497, and miR-340 are potential regulators of the immune evasion of breast cancer cells, and that they exert this function by targeting CD274, PDCD1LG2, and NCR3LG1. We chose CD274 for further investigations. We found that miR-195, miR-497, and CD274 expression levels were inversely correlated in MDA-MB-231 cells, and miR-195 and miR-497 expressions mimic inhibited CD274 expression in vitro. Mechanistic investigations demonstrated that miR-195 and miR-497 directly target CD274 3′ untranslated region. CONCLUSION: Our data indicated that the level of B7 family members can predict the prognosis of breast cancer patients, and miR-195/miR-497 regulate CD274 expression in triple negative breast cancer. This regulation may further influence tumor progression and the immune tolerance mechanism in breast cancer and may be able to predict the effect of immunotherapy on patients.

Resposta imune e mecanismos de evasão na carcinogênese de lábio: um estudo imunoistoquímico / Immune response and evasion mechanisms in lip carcinogenesis: an immunohistochemical study

A vigilância imunológica, principalmente mediada por linfócitos T CD8+ , reconhece e destrói células malignas ou alteradas. Contudo, através de estratégias imunossupressoras, como as vias de sinalização do ligante de morte celular programada-1 (PD-L1) e do antígeno leucocitário humano-G (HLA-G), estas células mutadas conseguem escapar da resposta imune antitumoral. Este estudo investigou a imunoexpressão de PD-L1, HLA-G, CD8 e granzima B (GrB) no microambiente de carcinomas de células escamosas (CCEs) de lábio (n = 40), de queilites actínicas (QAs; n = 55) e de mucosa labial saudável (MLS; n = 10). As amostras foram submetidas à técnica da imunoistoquímica e as análises das imunomarcações seguiram métodos semi-quantitativos (PD-L1 e HLA-G) e quantitativos (CD8 e GrB). A expressão das proteínas foi comparada entre os três grupos de amostras, bem como com parâmetros clinicopatológicos das lesões e sobrevida global dos pacientes com CCE de lábio. A correlação entre as proteínas e o tipo do microambiente tumoral de acordo com a presença de PD-L1 e CD8 também foram avaliados. Os testes estatísticos incluíram o exato de Fisher, Mann-Whitney, Kruskal-Wallis, correlação de Spearman e log-rank para comparação das curvas de sobrevida global construídas pelo método Kaplan-Meier. O nível de significância foi estabelecido em 5%. Os números de células CD8+ e GrB+ aumentaram progressivamente de MLS para CCEs de lábio, com QAs exibindo números intermediários (p < 0,01). A menor expressão dessas proteínas foi associada à metástase para linfonodos e tumores pobremente diferenciados (p < 0,05). A expressão de PD-L1 e HLA-G em células neoplásicas/ceratinócitos e estroma/tecido conjuntivo foi significativamente maior em CCEs de lábio e QAs, em comparação com MLSs (p < 0,05). PDL1 não foi significativamente associado aos aspectos clinicopatológicos das lesões. A maioria dos CCEs de lábio mostrou coexistência de células PD-L1+ e CD8+ (72,5%) no microambiente tumoral. A expressão de PD-L1 foi diretamente correlacionada à infiltração linfocítica CD8+ e GrB+ em CCEs de lábio (p < 0,05). A expressão das proteínas não foi associada com a sobrevida global dos pacientes com CCEs de lábio (p > 0,05). Nossos achados sugerem que as moléculas imunossupressoras PD-L1 e HLA-G estão consistentemente expressas desde QAs e se mantém até fases avançadas dos CCE de lábio. A correlação entre a expressão de PD-L1 e a expressão de CD8 e GrB nos carcinomas sugere que PD-L1 pode surgir como um mecanismo de escape frente a uma resposta antitumoral ativa (AU).

Immune surveillance, mainly mediated by CD8 + T lymphocytes, recognize and destroy malignant or altered cells. However, through immunosuppressive strategies, such as the signaling pathways of the programmed cell death ligand-1 (PD-L1) and human leukocyte antigen-G (HLA-G), these mutated cells often escape the antitumor immune response. The aim of this study was to investigate and compare the immunoexpression of PD-L1, HLA-G, CD8 and granzyme B (GrB) in the microenvironment of lip squamous cell carcinomas (LSCCs; n = 40), actinic cheilitis (ACs; n = 55), and healthy lip mucosa (HLM; n = 10). The samples were submitted to immunohistochemistry and the analysis followed a semi-quantitative (PD-L1 and HLA-G) and quantitative methods (CD8 and GrB). Protein expression was compared between the three groups of samples, as well as with the lesion's clinicopathologic parameters and overall survival of patients with LSCC. Correlation between proteins and the type of tumor microenvironment according to a presence of PD-L1 and CD8 were also evaluated. Statistical tests included Fisher's exact, Mann-Whitney, Kruskal-Wallis, Spearman's correlation, as well as the log-rank for comparison of the overall survival built through Kaplan-Meier method. Significance was set at p < 0.05. The CD8+ and GrB+ cell numbers progressively increased from HLMs to LSCCs, with ACs exhibiting intermediate numbers (p < 0.01). Lower expression of these proteins was associated with lymph node metastasis and poor tumor differentiation (p < 0.05). PD-L1 and HLA-G expression in neoplastic cells/keratinocytes and stroma/connective tissue was significantly higher in LSCCs and ACs, compared to HLMs (p < 0.05). PD-L1 was not significantly associated with clinicopathological aspects of the lesions. Most LSCCs showed coexistence of PD-L1+ and CD8+ cells (72.5%) in the tumor microenvironment. PDL1 was directly correlated to CD8+ and GrB+ lymphocytic infiltration in LSCCs (p < 0.05). Proteins expression was not associated with overall survival of LSCCs patients (p > 0.05). Our findings suggest that immunosuppressive molecules PD-L1 and HLA-G are consistently expressed from ACs and are maintained until advanced stages of LSCCs. The correlation between PD-L1 expression and the expression of CD8 and GrB in carcinomas suggests that that PD-L1 may appear as an escape mechanism against an active antitumor response (AU).

Innate immunity and HPV: friends or foes

Most human papillomavirus infections are readily cleared by the host immune response. However, in some individuals, human papillomavirus can establish a persistent infection. The persistence of high-risk human papillomavirus infection is the major risk factor for cervical cancer development. These viruses have developed mechanisms to evade the host immune system, which is an important step in persistence and, ultimately, in tumor development. Several cell types, receptors, transcription factors and inflammatory mediators involved in the antiviral immune response are viral targets and contribute to tumorigenesis. These targets include antigen-presenting cells, macrophages, natural killer cells, Toll-like receptors, nuclear factor kappa B and several cytokines and chemokines, such as interleukins, interferon and tumor necrosis factor. In the present review, we address both the main innate immune response mechanisms involved in HPV infection clearance and the viral strategies that promote viral persistence and may contribute to cancer development. Finally, we discuss the possibility of exploiting this knowledge to develop effective therapeutic strategies.

Immunological mechanisms of Neisseria gonorrhoeae infection: An update / 中华男科学杂志

Neisseria gonorrhoeae (NG), as a pathogen of gonorrhea, is strictly limited to growth on the human host. In case of gonococcal infection, the body may recruit such inflammatory cells as neutrophils to resist the invasion of NG or initiate its adaptive immune response by antigen presentation to eliminate the pathogen. However, a series of immune escape mechanisms of NG make it difficult to clear up the infection. In the innate immune system, NG can not only secrete thermonuclease to degrade neutrophile granulocytes, inhibit respiratory burst to resist killing by neutrophils, activate NLRP3 to prompt the pyronecrosis of inflammatory cells, but also regulate the differentiation of macrophages to reduce the inflammatory response, combine with factor H to evade complement-mediated killing. NG infection can hardly give rise to effective adaptive immune response and immune memory, but can promote TGF-β production to inhibit Th1/Th2-mediated adaptive immune response, bind to CEACAM1 on the B cell surface to promote apoptosis in B cells, and combine with CEACAM1 on the T cell surface to inhibit helper T cell proliferation, which makes it difficult for B cells to produce high-affinity specific antibodies. With the increasing drug-resistance of NG, immunological studies may play a significant role in the development of novel therapies and effective vaccines against the infection.

Pi (Spleen)-deficiency syndrome in tumor microenvironment is the pivotal pathogenesis of colorectal cancer immune escape / 中国结合医学杂志

Cancer immunoediting consists of three sequential phases: elimination, equilibrium, and escape. For colorectal adenoma-carcinoma sequence, the adenoma dysplastic progression may represent an equilibrium phase and the cancer stage as escape phase. Immune system eliminates transformed enterocytes by destroying them at first, sculpts them at the same time and selects the variants subsequently that are no longer recognized and insensitive to immune effectors, and finally induces immunosuppressive state within the tumor microenvironment that facilitates immune escape and tumor outgrowth. Immunosuppression and inflammation are the two crucial features of Pi (Spleen)-deficiency. Classic quotations, immune evidence and clinical observations suggest that Spleen (but not other organs) deficiency is the key pathogenesis of colorectal cancer (CRC) microenvironment. Weakness of old age, immunosuppressive cytokines from chronic inflammation, tumor-derived immunosuppressive factors and surrendered immune cells-regulatory T cells, myeloid-derived suppressor cells and tumor associated macrophages (TAMs) constitutes CRC microenvironment of Pi-deficiency. Furthermore, excess in superficiality, such as phlegm stagnation, blood stasis and toxin accumulation are induced by chronic inflammation on the basis of asthenia in origin, an immunosuppressive state. Great masters of Chinese medicine emphasize that strengthen Pi is the chief therapeutic principle for CRC which receives good therapeutic effects. So, Pi-deficiency based syndrome is the pivotal pathogenesis of tumor microenvironment. The immunosuppressive microenvironment facilitates immune escape which play an important role in the transition from adenoma to adenocarcinoma. There are some signs that strengthen Pi based treatment has potential capacity to ameliorate tumor environment. It might be a novel starting point to explore the mechanism of strengthen Pi based therapy in the prevention and treatment of CRC through regulation of tumor environment and immunoediting.

Characterization of Pv92, a Novel Merozoite Surface Protein of Plasmodium vivax

The discovery and understanding of antigenic proteins are essential for development of a vaccine against malaria. In Plasmodium falciparum, Pf92 have been characterized as a merozoite surface protein, and this protein is expressed at the late schizont stage, but no study of Pv92, the orthologue of Pf92 in P. vivax, has been reported. Thus, the protein structure of Pv92 was analyzed, and the gene sequence was aligned with that of other Plasmodium spp. using bioinformatics tools. The recombinant Pv92 protein was expressed and purified using bacterial expression system and used for immunization of mice to gain the polyclonal antibody and for evaluation of antigenicity by protein array. Also, the antibody against Pv92 was used for subcellular analysis by immunofluorescence assay. The Pv92 protein has a signal peptide and a sexual stage s48/45 domain, and the cysteine residues at the N-terminal of Pv92 were completely conserved. The N-terminal of Pv92 was successfully expressed as soluble form using a bacterial expression system. The antibody raised against Pv92 recognized the parasites and completely merged with PvMSP1-19, indicating that Pv92 was localized on the merozoite surface. Evaluation of the human humoral immune response to Pv92 indicated moderate antigenicity, with 65% sensitivity and 95% specificity by protein array. Taken together, the merozoite surface localization and antigenicity of Pv92 implicate that it might be involved in attachment and invasion of a merozoite to a new host cell or immune evasion during invasion process.

Ébolavirus: biología molecular y evasión de la respuesta inmune / Ebolavirus: molecular biology and immune response evasion

La actual epidemia de enfermedad por virus Ébola que azota al África Occidental ha cobrado la vida de alrededor de 9 000 personas con más de 22 000 infectados en seis países, y algunos casos aislados han llegado a ciudades de Europa y Estados Unidos. Aunque el curso clínico de la enfermedad es bien conocido, los mecanismos específicos que explican su patogenicidad no han sido completamente delineados. Los casos fatales de infección por Ébolavirus están marcados por un fallo catastrófico de las respuestas inmune innata y adaptativa, mediado por proteínas codificadas por el virus, así como por propiedades asociadas a su estructura. El genoma del Ébolavirus está constituido solamente por siete genes que codifican unas 10 proteínas, suficientes para desencadenar una enfermedad cuya letalidad varía del 40 al 90 por ciento. En el centro de la desregulación inducida por el Ébola se encuentra una temprana y coordinada actuación de las proteínas VP24, VP30 y VP35, que conduce a niveles elevados de replicación viral, a una inapropiada temporización de la cascada de liberación de linfocinas y a la muerte, tanto de células presentadoras de antígenos, como de células efectoras. Los complejos mecanismos del Ébola para regular selectivamente la respuesta inmune y su patogenicidad variable en diferentes especies hospederas, convierten a este virus en un adversario formidable, así como de un notable interés científico(AU)

The current Ebolavirus disease outbreak that strikes West Africa has claimed the life of around 9 000 people and has infected more than 22 000 in six countries, and some isolated cases have reached cities of Europe and the United States. Though the clinical course of the disease is well known, the specific mechanisms of its pathogenicity have not been fully delineated yet. Fatal cases of Ebolavirus disease are marked by a catastrophic failure of both innate and adaptive immune responses, mediated by virus-encoded proteins as well as properties associated with its structure. Ebolavirus genome comprises only seven genes encoding about 10 proteins, enough to cause a disease which fatality fluctuates from 40 to 90 percent. At the heart of Ebola-induced immune dysregulation is an early and coordinated disruption by VP24, VP30, and VP35 that leads to elevated levels of virus replication, a cascade of inappropriately timed cytokine release, and death of both antigen-presenting and responding immune cells. The complex mechanisms of Ebola to selectively regulate immune responses and its variable pathogenicity in different host species makes this virus both, a challenging foe and scientifically interesting(AU)

Challenging Mycobacterium tuberculosi s dormancy mechanisms and their immunodiagnostic potential

ABSTRACT Mycobacterium tuberculosis is the etiologic agent of tuberculosis, one of the world's greatest cause of morbidity and mortality due to infectious disease. Many evolutionary mechanisms have contributed to its high level of adaptation as a host pathogen. Prior to become dormant, a group of about 50 genes related to metabolic changes are transcribed by the DosR regulon, one of the most complex and important systems of host-pathogen interaction. This genetic mechanism allows the mycobacteria to persist during long time periods, establishing the so-called latent infection. Even in the presence of a competent immune response, the host cannot eliminate the pathogen, only managing to keep it surrounded by an unfavorable microenvironment for its growth. However, conditions such as immunosuppression may reestablish optimal conditions for bacterial growth, culminating in the onset of active disease. The interactions between the pathogen and its host are still not completely elucidated. Nonetheless, many studies are being carried out in order to clarify this complex relationship, thus creating new possibilities for patient approach and laboratory screening.

Evasión de la respuesta inmune por virus herpes simplex / Immune evasion by herpes simplex viruses

Herpes simplex viruses and humans have co-existed for tens of thousands of years. This long relationship has translated into the evolution and selection of viral determinants to evade the host immune response and reciprocally the evolution and selection of host immune components for limiting virus infection and damage. Currently there are no vaccines available to avoid infection with these viruses or therapies to cure them. Herpes simplex viruses are neurotropic and reside latently in neurons at the trigeminal and dorsal root ganglia, occasionally reactivating. Most viral recurrences are subclinical and thus, unnoticed. Here, we discuss the initial steps of infection by herpes simplex viruses and the molecular mechanisms they have developed to evade innate and adaptive immunity. A better understanding of the molecular mechanisms evolved by these viruses to evade host immunity should help us envision novel vaccine strategies and therapies that limit infection and dissemination.

Los virus herpes simplex y humanos co-existen desde decenas de miles de años. Esta prolongada relación se ha traducido en la evolución y selección de determinantes virales para evadir la respuesta inmune y recíprocamente la evolución y selección de componentes inmunes del hospedero para limitar la infección viral y el daño que producen. Actualmente no existen vacunas para evitar la infección de estos virus o terapias que la curen. Los virus herpes simplex son neurotrópicos y permanecen latentes en neuronas de ganglios trigémino y dorsales, reactivándose esporádicamente. La mayoría de las recurrencias por virus herpes simplex son sub-clínicas y por tanto pasan inadvertidas. Aquí discutimos los pasos iniciales de la infección porvirus herpes simplex y los mecanismos moleculares que estos virus han desarrollado para evadir la respuesta inmune innata y adaptativa. Una mejor comprensión de los mecanismos moleculares evolucionados por estos virus para evadir la respuesta inmune del hospedero deberían ayudarnos visualizar nuevas estrategias para desarrollar vacunas y terapias que limiten su infección y diseminación.