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Human B cells express Neuron/Glial 2 antigen. Possible implications for health and autoimmune disease of the central nervous system.
No full textNeuron/Glial 2 antigen (NG2) is a membrane proteoglycan expressed in many cellular types. In central nervous system (CNS), NG2 is expressed on oligodendrocyte precursor cells and on pericytes. NG2 is involved in cellular adhesion mechanisms, but its role is not completely clear. We showed that in the animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), NG2 is also expressed on immune cells like T cells, monocytes and dendritic cells (DCs) and that its expression on immune cells significantly influences the course of EAE, with NG2KO mice displaying a milder disease. In this study, we have assessed the expression of NG2 on human immune cells and its possible role in their activation in healthy donors (HD) and in patients affected by autoimmune diseases of CNS (MS and neuromyelitis optica (NMO)).
Monitoring of adaptive and innate cell immune populations for their expression of NG2 was performed by flow cytometry of B-, T- and natural killer cell subsets validating the use of a monoclonal anti-human NG2 antibody (clone 148.3). Our results on three HD blood samples indicated that while T cells do not express NG2, and NK cells express it to a very minor extent, 12.1 7.6% CD19+ B cells are NG2+. Accordingly, we have furthered our analysis to single B cell subsets, and show that about 25% B memory cells were NG2+, while NG2+ B regulatory and B mature cells are present in lesser amount (8%).
We showed that the frequency of NG2+ cells did not differ between HD (N=16) and patients with MS (N=16). Moreover, we investigated NG2 expression on B cells isolated from 2 patients affected with NMO, a rare predominantly B-cell-mediated autoimmune disease of CNS. In each of the two patients we observed a drastic increase in percentage of NG2+ B cells in the total B-cell population and on the different B-cell subsets as compared to HD or MS patients.
To evaluate a possible role of NG2 in immune cells activation, we studied NG2 expression upon in vitro activation of B cells. Interestingly, NG2 expression decreased upon activation of total CD19+ B cells. To assess if activation of B cells is associated with changes in NG2 expression, we stimulated separately sorted NG2+ and NG2- B cells. We demonstrated a mild decrease in NG2 expression on NG2+ sorted cells, whereas some NG2+ cells were observed in the NG2- sorted cells, indicating a possible correlation between cell-activation and NG2 expression. Moreover, we investigate NG2 expression on B cells collected form MS patients treated with alemtuzumab, an anti-CD52 monoclonal antibody associated with development of secondary B-cell-mediated autoimmune disease in 30% of patients. We, therefore, postulated the possibility that the autoimmunity risk might be associated with changes in NG2 expression on B cells and/or changes in frequency of NG2-expressing B cells. Accordingly, we investigated the impact of anti-CD52 treatment on NG2 expression on different B-cell subsets at times when secondary autoimmunity generally develops, in 7 treated patients. Notably, we observed that the treatment was associated to a significant decrease of B memory cells but we did not show any significant difference in frequency of NG2+ cells indicating that NG2+ cells are probably not involved in autoimmune adverse reactions related to the treatment.
In conclusion our data show for the first time that NG2 is expressed on human immune cells and in particular on B memory cells which play a crucial role in MS pathogenesis. The results suggest that NG2 expression fluctuates with B-cell activation, but further studies are necessary to better understand the possible role of NG2 on human immune cells
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Acute disseminated encephalomyelitis with severe neurological outcomes following virosomal seasonal influenza vaccine
No full textDispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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