Evidence that Maackia amurensis seed lectin (MASL) exerts pleiotropic actions on oral squamous cells with potential to inhibit SARS-CoV-2 infection and COVID-19 disease progression.

COVID-19 was declared an international public health emergency in January, and a pandemic in March of 2020. There are over 125 million confirmed COVID-19 cases that have caused over 2.7 million deaths worldwide as of March 2021. COVID-19 is caused by the SARS-CoV-2 virus. SARS-CoV-2 presents a surface "spike" protein that binds to the ACE2 receptor to infect host cells. In addition to the respiratory tract, SARS-Cov-2 can also infect cells of the oral mucosa, which also express the ACE2 receptor. The spike and ACE2 proteins are highly glycosylated with sialic acid modifications that direct viral-host interactions and infection. Maackia amurensis seed lectin (MASL) has a strong affinity for sialic acid modified proteins and can be used as an antiviral agent. Here, we report that MASL targets the ACE2 receptor, decreases ACE2 expression and glycosylation, suppresses binding of the SARS-CoV-2 spike protein, and decreases expression of inflammatory mediators by oral epithelial cells that cause ARDS in COVID-19 patients. In addition, we report that MASL also inhibits SARS-CoV-2 infection of kidney epithelial cells in culture. This work identifies MASL as an agent with potential to inhibit SARS-CoV-2 infection and COVID-19 related inflammatory syndromes.

Human keratinocyte cultures (HaCaT) can be infected by DENV, triggering innate immune responses that include IFNλ and LL37.

The skin is the first anatomical region that dengue virus (DENV) encounters during the natural infection. Although the role of some skin resident cells like dendritic cells and fibroblasts has been demonstrated to be crucial to elucidate the role of resident cells and molecules participating during the early events of the innate immune response, the participation of keratinocytes during DENV infection has not been fully elucidated. In this paper we aimed to evaluate the use of the HaCaT cell line as a model to study the immune responses of skin keratinocytes to DENV infection. We demonstrated productive DENV-2 infection of HaCaT cells and their capability to establish an antiviral response through production of type I and type III interferons (IFN-ß and IFN-λ). The production of these cytokines by HaCaT cells correlated with upregulation of IFN-inducible transmembrane protein-3 (IFITM3) and viperin in bystander, uninfected cells. We also observed an increase in secretion of IL-6 and IL-8. Skin keratinocytes are known to secrete antimicrobial peptides (AMPs) during viral infections. In our model, DENV-2 infected HaCaT cells upregulate the production of cytoplasmic LL-37. We evaluated the dual role of LL-37, HBD2, and HBD3 antiviral activity and immunoregulation during DENV-2 infection of HaCaT cells and found that LL-37 significantly reduced DENV-2 replication. This indicates that the HaCaT cell line can be used as a model for studying the innate response of keratinocytes to DENV infection. Our results also suggest that skin keratinocytes play an important role in the skin microenvironment after DENV infection by secreting molecules like type I and type III IFNs, pro-inflammatory molecules, and LL-37, which may contribute to the protection against arboviral infections.

DENV-2 subunit proteins fused to CR2 receptor-binding domain (P28)-induces specific and neutralizing antibodies to the Dengue virus in mice.

Domain III (DIII) of the dengue virus (DENV) envelope (E) protein induces strong neutralizing type-specific antibodies. In addition, a region near the fusion loop in domain II (DII) induces the production of cross-reactive antibodies with neutralizing potential. Thus, this study aimed to generate DENV-2 recombinant fusion proteins (i.e., rEII*EIII and rEII*EIII/NS1*) either alone or fused to 3 copies of P28, the minimum CR2-binding domain of the complement protein C3d. The 4 recombinant proteins were generated in a Drosophila melanogaster Schneider 2 (S2) cell system. The expression and secretion of the recombinant proteins were confirmed in vitro using immunofluorescence (IF) and western blot (WB) analyses. Human dengue immune serum samples recognized recombinant proteins. The immunogenicity of the 4 proteins in BALB/c mice was analyzed using ELISA, and the results revealed that the induced specific antibody response was higher in the groups of mice immunized with the P28 fusion proteins. Interestingly, although the 4 recombinant proteins were able to elicit high levels of neutralizing antibodies in BALB/c mice; no adjuvant effect was observed in terms of neutralizing antibodies in the groups immunized with proteins containing P28. Thus, ELISA and PRNT50 assays may evaluate different epitopes and responses, where ELISA showed a wider response that did not always correlate with neutralization. Furthermore, the elicited antibodies were able to recognize the immobilized E glycoprotein of DENV. All mice vaccinated with the DENV-2 recombinant proteins showed induction of higher levels of IgG1 antibodies than of IgG2a antibodies.

Targeting of envelope domain III protein of DENV type 2 to DEC-205 receptor elicits neutralizing antibodies in mice.

Dengue virus (DENV) is the causal agent of severe disease and, in some cases, mortality in humans, but no licensed vaccines against dengue are available. An effective vaccine against dengue requires long-term humoral and cellular immune responses. Several viral proteins have been the subjects of intense research, especially the envelope (E) protein, aimed at developing a vaccine. Domain III of the envelope protein (EDIII) has been identified as a potential candidate because it is involved in binding to host cell receptors and contains epitopes that elicit virus neutralizing antibodies. However, this domain is not sufficiently antigenic when is expressed and administered as antigen to elicit a strong immune response. One alternative to enhance immunogenicity is to target the antigen to dendritic cells to induce T-cells for broad antibody responses. In this work, a single chain antibody fragment (scFv) raised against the DEC-205 receptor fused with the EDIII was successfully expressed in Nicotiana benthamiana. The recombinant protein was expressed and purified from the plant and evaluated in BALB/c mice to test its immunogenicity and ability to induce neutralizing antibodies against DENV. The mice immunized with the recombinant protein produced specific and strong humoral immune responses to DENV. Only two immunizations were required to generate a memory response to DENV without the presence of adjuvants. Also, recognition of the recombinant protein with sera from DENV-infected patients was observed. These findings suggest that this strategy has potential for development of an effective vaccine against DENV.

La escleroris múltiple y sus variantes clínicas. Nuevas denominaciones / Sclerosis multiple and clinical variants. New denominations

En este resumen se describen algunos intentos de clasificación de la esclerosis múltiple desde el punto de vista funcional, inmunológico, patológico y sintomático. En consideración a este último aspecto, los pacientes afectados son agrupados de acuerdo con su evolución clínica

Nuevos fármacos contra la epilepsia / New drugs in epilepsy

En general 80 a 85 por ciento de los epilépticos se controlan satisfactoriamente con los medicamentos clásicos como son el defenilhidantoinato, la primidona, la carbamacepina y el ácido valproico. Sin embargo, entre 15 a 20 por ciento de los pacientes restantes no presenta un manejo adecuado con estos elementos clásicos y requiere de otra opción medicamentosa o de procedimientos quirúrgicos. En este sentido, han aparecido en el mercado norteamericano cutro productos de alternativa: el felbamato, vigabatrina, lamotrigina y oxcabacepina (trileptal), de los cuales se reseña el mecanismo de acción y empleo clínico.

Alteraciones de conducta como manifestaciones tempranas de la epilepsia / Behavior alterations as early manifestation of epilepsy

En el presente trabajo se han contemplado los defectos de atención y alteraciones de conducta que presentaban cinco niños, como fenómenos que precedieron a manifestaciones de epilepsia. Con tal motivo, se hizo el seguimiento clínico de estos pacientes por un periodo de seis meses a dos años antes de presentar la primera crisis de epilepsia. Po lo expresado, se considera que la atención y conducta alteradas deben tenerse presentes como fenómenos clínicos tempranos, para prevenir o esperar una posible epilepsia en presencia de un electroencefalograma anormal