Diversity of immunoglobulin light chain genes in non-teleost ray-finned fish uncovers IgL subdivision into five ancient isotypes

<p>The aim of this study was to fill important gaps in the evolutionary history of immunoglobulins by examining the structure and diversity of IgL genes in non-teleost ray-finned fish. First, based on the bioinformatic analysis of recent transcriptomic and genomic resources, we experimentally characterized the IgL genes in the chondrostean fish, Acipenser ruthenus (sterlet). We show that this species has three loci encoding IgL kappa-like chains with a translocon-type gene organization and a single VJC cluster, encoding homogeneous lambda-like light chain. In addition, sterlet possesses sigma-like VL and J-CL genes, which are transcribed separately and both encode protein products with cleavable leader peptides. The Acipenseriformes IgL dataset was extended by the sequences mined in the databases of species belonging to other non-teleost lineages of ray-finned fish: Holostei and Polypteriformes. Inclusion of these new data into phylogenetic analysis showed a clear subdivision of IgL chains into five groups. The isotype described previously as the teleostean IgL lambda turned out to be a kappa and lambda chain paralog that emerged before the radiation of ray-finned fish. We designate this isotype as lambda-2. The phylogeny also showed that sigma-2 IgL chains initially regarded as specific for cartilaginous fish are present in holosteans, polypterids, and even in turtles. We conclude that there were five ancient IgL isotypes, which evolved differentially in various lineages of jawed vertebrates.</p

CXCL8 Chemokines in Teleost Fish: Two Lineages with Distinct Expression Profiles during Early Phases of Inflammation

Contains fulltext : 126584.pdf (publisher's version ) (Open Access

VH3-53/66-Class RBD-Specific Human Monoclonal Antibody iB20 Displays Cross-Neutralizing Activity against Emerging SARS-CoV-2 Lineages

Immune evasion of SARS-CoV-2 undermines current strategies tocounteract the pandemic, with the efficacy of therapeutic virus-neutralizing monoclonal antibodies (nAbs) being affected the most. In this work, we asked whether two previously identified human cross-neutralizing nAbs, iB14 (class VH1-58) and iB20 (class VH3-53/66), are capable of neutralizing the recently emerged Omicron (BA.1) variant. Both nAbs were found to bind the Omicron RBD with a nanomolar affinity, yet they displayed contrasting functional features. When tested against Omicron, the neutralizing activity of iB14 was reduced 50-fold, whereas iB20 displayed a surprising increase in activity. Thus, iB20 is a unique representative of the VH3-53/66-class of nAbs in terms of breadth of neutralization, which establishes it as a candidate for COVID-19 therapy and prophylactics

The expression of a novel CD150 splice isoform (nCD150).

<p>(A) Schematic representation of the CD150/SLAM gene structure and alternative splicing of mRNA. The exon designated Cyt-new is flanked with canonical splice sites (AG/GT marked in grey in the above genomic sequence). Exons are shown by filled rectangles, noncoding sequences—by solid line. Abbreviations: LS—leader sequence, V and C2—extracellular domains, TM—transmembrane domain, Cyt—cytoplasmic tail. (B) Expression of a nCD150 splice isoform was found in TE671, A172, U343, NCH92, NCH89 and U87 glioma cell lines, human tonsillar B cells (TBC) and cell lines of B cell origin, human acute monocytic leukemia cell line THP-1 and dendritic cells (DC), T cells (CD3⁺), monocytes (Mon) and macrophages (Mac), but it was not detected in human primary monocytes (Mon). The quality and quantity of cDNA was monitored by GAPDH expression. One of three representative experiments.</p

Real-time-PCR analysis of CD150 splice isoforms expression in glioma cell lines and primary tumors.

<p>We used 6 glioblastoma cell lines, four glioma tumor samples (GB1, GB2—glioblastoma, AODG—anaplastic oligodendroglioma, DA—diffuse astrocytoma), human tonsillar CD38⁺ B cells and lymphoblastoid cell line T5–1 for the analysis. Expression level of mRNA coding for each CD150 isoform was calculated using (ddCt) method, normalized to TBP and then expressed relative to respective isoform in CD38⁺ B cells, the value for which was set at 1. The results, presented as mean of triplicates (±SEM), are from one of three independent experiments. In glioma cell lines and glioma primary tumors the novel CD150 isoform is expressed at the high level, while the isoforms with the conventional cytoplasmic tail are absent or detected at the low level.</p

Expression of CD150 in human glioma cell lines.

<p>(A) Flow cytometry study of CD150 surface expression on U87, U343 and A172 cells. One of four experiments. (B) Immunofluorescent analysis of CD150 expression in the cytoplasm of U87, U343 and A172 glioma cell lines. The cells were fixed, stained with anti-CD150 antibodies (IPO-3) followed by secondary antibody labelled with Alexa 488 (upper panel). Nuclei were visualized by staining with DAPI (middle panel). Results are representative of more than five experiments. Magnification: 630×. (C) Western blot analysis of CD150 expression in glioma cell lines using rabbit monoclonal anti-CD150 antibodies (Sino Biologicals Inc., China). Pre-B cell line REH and B-LCL MP-1 (in two different dilutions) were used as negative and positive controls respectively. One of five experiments is presented. The flow cytometry analysis of live cells does not show any CD150 expression in all used glioma cell lines, however fluorescent studies of fixed permeabilized cells and western blot detected CD150 expression in U87, U343, U251, TE671, NCH84, and NCH92 glioma cell lines.</p

Colocalization of CD150 with the markers of endoplasmic reticulum and Golgi apparatus.

<p>U87 or MP-1 cells were stained for CD150 (green) and the markers of endoplasmic reticulum (A) or Golgi apparatus (B) (red). Markers for endoplasmic reticulum—kinectin-1 and GRP78, for Golgi—furin. Nuclei were visualized by staining with DAPI (4’,6-diamidino-2-phenylindole). Colocalization coefficients were determined using the Manders algorithm (which ranges from 0 to 1, where 0 is defined as no colocalization and 1 as perfect colocalization) and are indicated within the panels. Confocal microscopy shows the similar high colocalisation of CD150 and ER markers in both types of cells, but significantly lower colocalisation of CD150 and Golgi marker in glioma cell line U87 comparing to B cell line MP-1. Microscopic magnification of 630× was used for all pictures. Digital magnification of 3150× was made for the insertions. The data are presented as mean ± SD (n = 7).</p