Cavazzoni CB, Bozza VBT, Lucas TCV, Conde L, Maia B, Mesin L, Schiepers A, Ersching J, Neris RLS, Conde JN, Coelho DR, Lima TM, Alvim RGF, Castilho LR, de Paula Neto HA, Mohana-Borges R, Assunção-Miranda I, Nobrega A, Victora GD, Vale AM. The immunodominant antibody response to Zika virus NS1 protein is characterized by cross-reactivity to self. J Exp Med. 2021 Sep 6;218(9):e20210580. 

DOI: 10.1084/jem.20210580

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Besides antigen-specific responses to viral antigens, humoral immune response in virus infection can generate polyreactive and autoreactive antibodies. Dengue and Zika virus infections have been linked to antibody-mediated autoimmune disorders, including Guillain-Barré syndrome. A unique feature of flaviviruses is the secretion of nonstructural protein 1 (NS1) by infected cells. NS1 is highly immunogenic, and antibodies targeting NS1 can have both protective and pathogenic roles. In the present study, we investigated the humoral immune response to Zika virus NS1 and found NS1 to be an immunodominant viral antigen associated with the presence of autoreactive antibodies. Through single B cell cultures, we coupled binding assays and BCR sequencing, confirming the immunodominance of NS1. We demonstrate the presence of self-reactive clones in germinal centers after both infection and immunization, some of which present cross-reactivity with NS1. Sequence analysis of anti-NS1 B cell clones showed sequence features associated with pathogenic autoreactive antibodies. Our findings demonstrate NS1 immunodominance at the cellular level as well as a potential role for NS1 in ZIKV-associated autoimmune manifestations.

SOUSA, S. M. dos S.; BANDEIRA, D. R.; QUINTANILHA , L. F. da C.; BALDAÇARA, R. P. de C.; CAVALCANTE, C. P. A.; SILVA, J. B. N. F. The influence of the gut microbiota on the development of food allergy in children . Research, Society and Development, [S. l.], v. 10, n. 14, p. e293101422156, 2021.

DOI: 10.33448/rsd-v10i14.22156

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The gut microbiota, which is formed mainly early in life, plays a crucial role in the formation of the immune system and in food tolerance. Dysbiosis, which means an overgrowth of pathobiont bacteria, creates imbalance and inflammation of the gut microbiota, affecting its function. Because of this, there was interest in evaluating the influence of the microbiota on the development of food allergies in children, analyzing the interference of dysbiosis on the immune system, by the method of integrative review in the last 10 years, since there is an increase in the prevalence of food allergies in children in the last decade. This research is characterized as an integrative literature review, in which articles published in the last 10 years, selected through the inclusion criteria, were analyzed. It is based on the theme "The influence of the microbiota on the development of food allergy in children". Literature published in English, Portuguese and Spanish was sought as the study priority. The intestinal microbiota is directly related to the immune system, and malfunction of one is followed by imbalance of the other. Thus, the composition of a comprehensive and functional gut microbiota contributes to a more resilient immune system and can lead to a greater tolerance to food allergies. However, we conclude that dysbiosis is more conducive to the onset of allergies. Despite the genetic contribution, it has the contribution of environmental factors and hygienic factors that favor the onset of food allergy.

Keywords:  microbiota; dysbiosis; food hypersensitivity.; Dysbiosis; Food hypersensitivity.

Neris RLS, Dobles AMC, Gomes AV. Western Blotting Using In-Gel Protein Labeling as a Normalization Control: Advantages of Stain-Free Technology. Methods Mol Biol. 2021;2261:443-456.

DOI: 10.1007/978-1-0716-1186-9_28

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Western blotting is one of the most used techniques in research laboratories. It is popular because it is an easy way of semiquantifying protein amounts in different samples. In Western blotting, the most commonly used method for controlling the differences in the amount of protein loaded is to independently quantify housekeeping proteins (typically actin, GAPDH or tubulin). Another less commonly used method is total protein normalization using stains, such as Ponceau S or Coomassie Brilliant Blue, which stains all the proteins on the blots. A less commonly used but powerful total protein staining technique is stain-free normalization. The stain-free technology is able to detect total protein in a large linear dynamic range and has the advantage of allowing protein detection on the gel before transblotting. This chapter discusses the theory, advantages, and method used to do total protein quantification using stain-free gels for normalization of Western blots.

Keywords: Immunoblotting, Loading control, Stain-free technology, Total protein normalization, Western blotting

da Silva-Junior EB, Firmino-Cruz L, Guimarães-de-Oliveira JC, De-Medeiros JVR, de Oliveira Nascimento D, Freire-de-Lima M, de Brito-Gitirana L, Morrot A, Previato JO, Mendonça-Previato L, Decote-Ricardo D, de Matos Guedes HL, Freire-de-Lima CG. The role of Toll-like receptor 9 in a murine model of Cryptococcus gattii infection. Sci Rep. 2021 Jan 14;11(1):1407.

DOI: 10.1038/s41598-021-80959-5

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Toll-like receptor 9 (TLR9) is crucial to the host immune response against fungi, such as Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans, but its importance in Cryptococcus gattii infection is unknown. Our study aimed to understand the role of TLR9 during the course of experimental C. gattii infection in vivo, considering that the cryptococcal DNA interaction with the receptor could contribute to host immunity even in an extremely susceptible model. We inoculated C57BL/6 (WT) and TLR9 knock-out (TLR9-/-) mice intratracheally with 104 C. gattii yeast cells. TLR9-/- mice had a higher mortality rate compared to WT mice and more yeast cells that had abnormal size, known as titan cells, in the lungs. TLR9-/- mice also had a greater number of CFUs in the spleen and brain than WT mice, in addition to having lower levels of IFN-γ and IL-17 in the lung. With these markers of aggressive cryptococcosis, we can state that TLR9-/- mice are more susceptible to C. gattii, probably due to a mechanism associated with the decrease of a Th1 and Th17-type immune response that promotes the formation of titan cells in the lungs. Therefore, our results indicate the participation of TLR9 in murine resistance to C. gattii infection.

Diniz-Lima I, da Rosa PR, da Silva-Junior EB, Guimarães-de-Oliveira JC, de Freitas EO, de Oliveira Nascimento D, Morrot A, Nimrichter L, Previato JO, Mendonça-Previato L, Freire-de-Lima L, Decote-Ricardo D, Freire-de-Lima CG. X-linked immunodeficient (XID) mice exhibit high susceptibility to Cryptococcus gattii infection. Sci Rep. 2021 Sep 15;11(1):18397.

DOI: : 10.1038/s41598-021-97041-9

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Cryptococcosis is an opportunistic disease caused by the fungus Cryptococcus neoformans and Cryptococcus gattii. It starts as a pulmonary infection that can spread to other organs, such as the brain, leading to the most serious occurrence of the disease, meningoencephalitis. The humoral response has already been described in limiting the progression of cryptococcosis where the B-1 cell seems to be responsible for producing natural IgM antibodies, crucial for combating fungal infections. The role of the B-1 cell in C. neoformans infection has been initially described, however the role of the humoral response of B-1 cells has not yet been evaluated during C. gattii infections. In the present study we tried to unravel this issue using XID mice, a murine model deficient in the Btk protein which compromises the development of B-1 lymphocytes. We use the XID mice compared to BALB/c mice that are sufficient for the B-1 population during C. gattii infection. Our model of chronic lung infection revealed that XID mice, unlike the sufficient group of B-1, had early mortality with significant weight loss, in addition to reduced levels of IgM and IgG specific to GXM isolated from the capsule of C. neoformans. In addition to this, we observed an increased fungal load in the blood and in the brain. We described an increase in the capsular size of C. gattii and the predominant presence of cytokines with a Th2 profile was also observed in these animals. Thus, the present study strongly points to a higher susceptibility of the XID mouse to C. gattii, which suggests that the presence of B-1 cells and anti-GXM antibodies is fundamental during the control of infection by C. gattii.

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