Monoallelic IRF5 deficiency in B cells prevents murine lupus.

Gain-of-function polymorphisms in the transcription factor IFN regulatory factor 5 (IRF5) are associated with an increased risk of developing systemic lupus erythematosus. However, the IRF5-expressing cell type(s) responsible for lupus pathogenesis in vivo is not known. We now show that monoallelic IRF5 deficiency in B cells markedly reduced disease in a murine lupus model. In contrast, similar reduction of IRF5 expression in macrophages, monocytes, and neutrophils did not reduce disease severity. B cell receptor and TLR7 signaling synergized to promote IRF5 phosphorylation and increase IRF5 protein expression, with these processes being independently regulated. This synergy increased B cell-intrinsic IL-6 and TNF-α production, both key requirements for germinal center (GC) responses, with IL-6 and TNF-α production in vitro and in vivo being substantially lower with loss of 1 allele of IRF5. Mechanistically, TLR7-dependent IRF5 nuclear translocation was reduced in B cells from IRF5-heterozygous mice. In addition, we show in multiple lupus models that IRF5 expression was dynamically regulated in vivo with increased expression in GC B cells compared with non-GC B cells and with further sequential increases during progression to plasmablasts and long-lived plasma cells. Overall, a critical threshold level of IRF5 in B cells was required to promote disease in murine lupus.

Estabelecimento in vitro de explantes de três cultivares de bananeira / Explants establishment in vitro of three banana cultivars

O objetivo do presente trabalho foi avaliar dois protocolos de desinfestação na micropropagação em três cultivares de bananeira. Utilizaram-se mudas das cultivares de bananeira Prata Anã, FHIA 18 e SH3640. Os protocolos 1 e 2 de desinfestação (Des. 1 e Des. 2) foram realizados utilizando-se os seguintes produtos: solução fungicida de Derosol, álcool comercial, solução de hipoclorito de sódio e de hipoclorito de cálcio e tween 20, apresentando variações na concentração dos produtos em cada um dos protocolos. As avaliações para a porcentagem de contaminação foram realizadas diariamente por meio do número total de tubos contaminados e não contaminados. O delineamento foi em blocos casualizados, com quatro repetições, em um sistema fatorial. As contaminações que ocorreram foram causadas exclusivamente por bactérias. Independentemente do tratamento utilizado, os índices de contaminação foram superiores a 29 por cento para as três cultivares testadas. Estes resultados indicam a necessidade de adequar novas metodologias de assepsias de explantes de bananeira.

The purpose of this work was to evaluate two protocols of disinfestations in the micropropagation on young plants of three banana cultivars: Prata-Anã, FHIA 18 and SH3640. Protocols 1 and 2 of disinfestations (Dis. 1 and Dis. 2) were carried out using the products: fungicidal solution of Derosol, commercial alcohol, solution of sodium hypo chlorite and calcium hypo chlorite and tween 20, presenting variations in their concentration in every one of the protocols. The evaluations for contamination rate were taken daily by means of the total number of contaminated and non-contaminated tubes. A random block design in a factorial scheme with four repetitions was used. Exclusively bacteria had caused all contamination. Independently of the used treatment the contamination levels had been up to 29 percent for all the three cultivars tested. These results indicate the necessity of adjusting the new methodologies of asepses of banana explants.