Expression of the HOX-2.3 homeobox gene in human lymphocytes and lymphoid tissues

Abstract Homeobox proteins are sequence-specific DNA-binding proteins initially implicated in the control of gene expression in developing tissues; however, there is increasing evidence that these proteins are important in gene regulation in adult tissues. A cDNA for the homeobox gene HOX- 2.3 was isolated from an adult human B-lymphocyte cDNA library. Northern blot analysis showed expression of a 1.1 and a 1.6 kb messenger RNA (mRNA) in a human B-cell line. RNase protection assays demonstrated variable expression in both human B- and T-cell lines. Virally transformed and nontransformed lymphocyte cell lines expressed HOX-2.3 transcripts. Essentially no transcripts were found in unactivated normal B and T lymphocytes; however, B-cell activation with Staphylococcus aureus Cowan strain I and phorbol myristate acetate (PMA) or T-cell activation with phytohemagglutinin and PMA were accompanied by a rapid induction of HOX-2.3 expression even in the presence of the protein synthesis inhibitor, cycloheximide. In situ hybridization was performed to examine HOX-2.3 expression in lymphoid tissues. HOX-2.3 mRNA was detected in the thymic cortex from an 8-year- old child, in the germinal centers in adult tonsil, and in a limited number of hematopoietic cells from the bone marrow. These findings suggest the involvement of HOX-2.3 in regulating gene transcription not only in developing tissues but in hematopoietic and lymphoid tissues as well.

Download Full-text

Expression of the HOX-2.3 homeobox gene in human lymphocytes and lymphoid tissues

Blood ◽

10.1182/blood.v78.2.445.bloodjournal782445 ◽

1991 ◽

Vol 78 (2) ◽

pp. 445-450

Author(s):

Y Deguchi ◽

JF Moroney ◽

JH Kehrl

Keyword(s):

T Cell ◽

B Cell ◽

Cell Lines ◽

Cell Activation ◽

Homeobox Gene ◽

Protein Synthesis Inhibitor ◽

Lymphoid Tissues ◽

Rnase Protection ◽

Control Of Gene Expression ◽

Variable Expression

Homeobox proteins are sequence-specific DNA-binding proteins initially implicated in the control of gene expression in developing tissues; however, there is increasing evidence that these proteins are important in gene regulation in adult tissues. A cDNA for the homeobox gene HOX- 2.3 was isolated from an adult human B-lymphocyte cDNA library. Northern blot analysis showed expression of a 1.1 and a 1.6 kb messenger RNA (mRNA) in a human B-cell line. RNase protection assays demonstrated variable expression in both human B- and T-cell lines. Virally transformed and nontransformed lymphocyte cell lines expressed HOX-2.3 transcripts. Essentially no transcripts were found in unactivated normal B and T lymphocytes; however, B-cell activation with Staphylococcus aureus Cowan strain I and phorbol myristate acetate (PMA) or T-cell activation with phytohemagglutinin and PMA were accompanied by a rapid induction of HOX-2.3 expression even in the presence of the protein synthesis inhibitor, cycloheximide. In situ hybridization was performed to examine HOX-2.3 expression in lymphoid tissues. HOX-2.3 mRNA was detected in the thymic cortex from an 8-year- old child, in the germinal centers in adult tonsil, and in a limited number of hematopoietic cells from the bone marrow. These findings suggest the involvement of HOX-2.3 in regulating gene transcription not only in developing tissues but in hematopoietic and lymphoid tissues as well.

Download Full-text

SAT0187 DISCRIMINATION OF SYSTEMIC LUPUS (SLE) PATIENTS WITH CLINICAL RESPONSE TO OBEXELIMAB (XMAB®5871) BASED ON A PATTERN OF IMMUNOLOGIC MARKERS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.2972 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1035-1036

Author(s):

J. T. Merrill ◽

J. Guthridge ◽

D. Zack ◽

P. Foster ◽

B. Burington ◽

...

Keyword(s):

T Cell ◽

B Cell ◽

Clinical Response ◽

Plasma Cell ◽

Cell Activation ◽

High Expression ◽

Research Support ◽

Variable Expression ◽

Cell Modules ◽

Immune Pathway

Background:We recently reported Phase 2 SLE trial results of obexelimab, an FcγRIIb agonist (suppressor of B cell activation). Obexelimab did not meet the primary endpoint (% of patients without flare at Day 225) (p=0.183) but other endpoints such as time to flare (p=0.025) were met.Objectives:1. To assign SLE patients to phenotypic subsets based on patterns of gene expression in immune-related pathways.12. To explore the association of immune patterns and clinical response to obexelimab.Methods:This analysis included 71 of the 104 participants in the obexelimab study, those who either completed the protocol or terminated for disease flare, if there were adequate blood samples (biomarker subset). At screening, patients were assigned to clusters based on 41 SLE co-expression signature modules from the Human Immune Phenotyping Consortium via unsupervised random forest and K-means clustering.2Other markers of SLE disease were also examined. TheBOLD3study design mandated withdrawal of background immunosuppressants, supporting less ambiguous pharmacodynamic analysis as the trial progressed.Results:Immune pathway expression patterns of 7 patient clusters (Fig 1a) confirmed our prior characterization of 200 non-overlapping SLE patients.2The biomarker subset retained a trend of longer time to first flare in patients receiving obexelimab (n=38) vs placebo (n=33) (Fig1b, HR 0.61, p=0.11). A smaller set of only Clusters 3 and 6 demonstrated marked increased time to flare in the obexelimab group (n=13) compared to placebo (n=14) (Fig 1c, HR 0.22, p=0.025). Obexelimab had no effect on other clusters (Fig 1d). The responder clusters shared low expression of inflammation modules (p < 0.001) compared to other clusters and high expression of T Cell, immune response, cell cycle, mitochondrial modules (all p < 0.001) and B Cell modules (p=0.006). We therefore sorted patients by these specific features regardless of cluster assignment. Figure 2 shows significant impact of obexelimab on time to flare in 64 patients with B Cell pathway activation (HR 0.5, p=0.038), although less robust by itself than found in Clusters 3 and 6. In a group with high B or plasma cell modules but low inflammation (n=46), treatment effect increased (HR 0.35, p=0.019). Between Screening and Baseline, as brief steroids were given and background treatments withdrawn, expression of B Cell and Plasma Cell pathways increased. Both then decreased after treatment with obexelimab but not placebo (p< 0.0001 and p< 0.001 respectively), an effect not seen with other immune pathway modules.Conclusion:Precision medicine for SLE has been hampered by heterogenous immune signals with variable expression. Clustering of patients by gene co-expression pathways enabled an efficient, hierarchical array that reduplicated results of a prior SLE cohort, suggesting these are not random phenotypes. Of these 7 reproducible SLE subsets, the combination of clusters 3 and 6 distinguished an obexelimab responder population of 27 out of 71 subjects (38%) with high expression of B and T Cell modules and cell activation pathways. Focus on the defining features shared by these clusters revealed specific factors associated with response, enabling inclusion of some patients from other clusters in an optimized responder population of 46/71 (65% of subjects). B Cell and Plasma Cell pathways demonstrated mechanism-related pharmacodynamic effects of obexelimab. Lack of responders with high expression of inflammation modules could implicate inhibitory factors to obexelimab within inflammatory pathways, potentially targetable by complementary treatments.References:[1]Banchereau Cell 165:1548 2016[2]Lu ACR Abstract #2977 2017[3]Merrill Arthritis Rheumatol 69: 1257 2017Disclosure of Interests: :Joan T Merrill Grant/research support from: Xencor, Bristol Myers Squibb, Glaxo Smith Kline, Consultant of: Xencor, Abbvie, UCB, Glaxo Smith Kline, EMD Serono, Astellas, Remegen, Celgene/Bristol Myers Squibb, Exagen, Astra Zeneca, Amgen, Jannsen, Servier, ILTOO, Daitchi Sankyo, Lilly, Paid instructor for: Abbvie, Bristol Myers Squibb, Joel Guthridge Grant/research support from: Xencor, Bristol Myers Squibb, DXterity, Debra Zack Shareholder of: Xencor, Employee of: Xencor, Paul Foster Shareholder of: Xencor Inc, Employee of: Xencor Inc, Bart Burington Shareholder of: Xencor Inc, Employee of: Xencor Inc, Ly Tran: None declared, Miles Smith: None declared, Judith A. James Grant/research support from: Progentec Diagnostics, Inc, Consultant of: Abbvie, Novartis, Jannsen

Download Full-text

Normal and Aberrant NKL-Code in B-Cell Development and Lymphoma

Blood ◽

10.1182/blood-2018-99-110286 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3901-3901

Author(s):

Stefan Nagel ◽

MacLeod A.F. Roderick ◽

Corinna Meyer ◽

Maren Kaufmann ◽

Hans G. Drexler

Keyword(s):

T Cell ◽

B Cells ◽

B Cell ◽

Cell Lines ◽

Cell Lymphoma ◽

Homeobox Genes ◽

Homeobox Gene ◽

B Cell Lymphoma ◽

Cell Development ◽

B Cell Development

Abstract Homeobox genes encode transcription factors which regulate basic processes in development and cell differentiation. Several members of the NKL subclass are deregulated in T-cell progenitors and support leukemogenesis. We have recently described particular expression patterns of nine NKL homeobox genes in early hematopoiesis and T-cell development. Here, we screened NKL homeobox gene activities in normal B-cell development and extended the NKL-code to include this lymphoid lineage. Analysis of public expression profiling datasets revealed that HHEX and NKX6-3 were the only members differentially active in naïve B-cells, germinal center B-cells, plasma cells and memory B-cells. Subsequent examination of different types of B-cell malignancies showed both aberrant overexpression of NKL-code members and ectopic activation of subclass members physiologically silent in lymphopoiesis including BARX2, DLX1, EMX2, NKX2-1, NKX2-2 and NKX3-2. Based on these findings we performed detailed studies of the B-cell specific NKL homeobox gene NKX6-3 which showed enhanced activity in patient subsets of follicular lymphoma, mantle cell lymphoma and diffuse large B-cell lymphoma (DLBCL), and in three DLBCL cell lines to serve as in vitro models. While excluding genomic and chromosomal rearrangements at the locus of NKX6-3 (8p11) promoter studies demonstrated that B-cell factors MYB and PAX5 activated NKX6-3 transcription. Furthermore, aberrant BMP7/SMAD1-signalling and deregulated expression of chromatin complex components AUTS2 and PCGF5 promoted NKX6-3 activation. Finally, NKL homeobox genes HHEX, HLX, MSX1 and NKX6-3 were expressed in B-cell progenitors and generated a regulatory gene network in cell lines which we propose may provide physiological support for NKL-code formation in early B-cell development. Together, we identified an NKL-code in B-cell development whose violation may deregulate differentiation and promote malignant transformation. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Mechanisms regulating IgA class-specific immunoglobulin production in murine gut-associated lymphoid tissues. I. T cells derived from Peyer's patches that switch sIgM B Cells to sIgA B cells in vitro

Journal of Experimental Medicine ◽

10.1084/jem.157.2.433 ◽

1983 ◽

Vol 157 (2) ◽

pp. 433-450 ◽

Cited By ~ 191

Author(s):

H Kawanishi ◽

LE Saltzman ◽

W Strober

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Cell Lines ◽

Cell Cultures ◽

Peyer's Patches ◽

Lymphoid Tissues ◽

Peyer’S Patches ◽

Ig Synthesis

To explore mechanisms of T cell regulation governing mucosal IgA immune response, concanavalin A-induced cloned T cell lines from Peyer's patches (PP) as well as spleen were established. The cloned cell lines expressed Thy- 1.2(+), Lyt-l(+)2(-) and were radioresistant (1,500 rad). The capacity of the cloned T cells to regulate Ig synthesis was determined by measuring their effect on lipopolysaccharide (LPS)-induced polyclonal Ig synthesis by PP B cells. In initial studies Ig secreted by B cells was determined by double antibody radioimmunoassay. LPS in the absence of cloned T cells induced abundant amounts of IgM (average 8,860 ng/2 × 10(5) B cells) and IgG (average 1,190 ng/2 × 10(5) B cells), but little or no IgA. The addition of PP cloned T cells markedly suppressed production of IgM (88 percent at the highest T/B cell ratio, 4:1), but the addition of spleen cloned T cells suppressed only a little or not at all. IgG production was inhibited by both PP and spleen T clone cells (70 percent at the 4:1 T/B ratio), wheras IgA synthesis was enhanced by both clones, but only to a limited degree. In subsequent studies the expression of class-specific surface Ig (sIg) and cytoplasmic Ig (cIg) on/in unseparated PP B cells as well as Ig class- specific PP B cells and spleen B cells during culture with or without the cloned T cells was determined by immunofluorescence. The major findings were as follows: (a) Compared with unseparated B cell cultures and cultures of purified sIgM B cells derived from PP containing LPS alone, cultures containing LPS and PP cloned T cells showed a marked decrease in cIgM-, sIgG-, and cIgG-expressing cells that was accompanied by a striking increase in sIgA-bearing, but not cIgA-containing, cells. In contrast, unseparated B cell cultures and cultures of purified sIgM B cells derived from PP containing LPS and spleen cloned T cells did not show any increase in sIgA- bearing cells. (b) Compared with purified sIgG-bearing PP B cell cultures containing LPS alone, purified sIgG-bearing PP B cell cultures containing both LPS and PP cloned T cells showed no substantial change in sIgG- or cIgG- expressing cells, and no sIgA- or cIgA- expressing cells appeared. (c) Compared with sIgA-bearing PP B cell cultures containing LPS alone, purified sIgA-bearing PP B cell cultures containing both LPS and PP cloned T cells showed no increased proliferation, and cIgA cells did not occur. Cultures of purified sIgM B cells derived from spleen containing LPS and PP cloned T cells showed qualitatively similar changes. From these results we conclude that PP cloned T cells induced class-specific switching from sIgM- to sIgA- bearing B cells, whereas spleen cloned T cells lacked this property, although they may have induced an IgM {arrow} IgG or intersubclass IgG switch. These processes seem to be in part tissue dependent. Furthermore, the PP switch T cells appear to operate as true switch cells, which govern the pathway of DNA recombination events, rather than as classical helper cells, which act to expand already differentiated cells. Finally, these switch T cells probably account for the fact that PP are an important source of IgA B cells and also a major site of IgA heavy chain class switching during gut-associated mucosal B cell proliferation and differentation.

Download Full-text

CD32+CD4+ T Cells Sharing B Cell Properties Increase With Simian Immunodeficiency Virus Replication in Lymphoid Tissues

Frontiers in Immunology ◽

10.3389/fimmu.2021.695148 ◽

2021 ◽

Vol 12 ◽

Author(s):

Nicolas Huot ◽

Philippe Rascle ◽

Cyril Planchais ◽

Vanessa Contreras ◽

Caroline Passaes ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cell ◽

T Cell Activation ◽

Cd4 T Cells ◽

Cell Activation ◽

Lymphoid Tissues ◽

Cell Responses ◽

Immunodeficiency Virus ◽

Siv Infection

CD4 T cell responses constitute an important component of adaptive immunity and are critical regulators of anti-microbial protection. CD4+ T cells expressing CD32a have been identified as a target for HIV. CD32a is an Fcγ receptor known to be expressed on myeloid cells, granulocytes, B cells and NK cells. Little is known about the biology of CD32+CD4+ T cells. Our goal was to understand the dynamics of CD32+CD4+ T cells in tissues. We analyzed these cells in the blood, lymph nodes, spleen, ileum, jejunum and liver of two nonhuman primate models frequently used in biomedical research: African green monkeys (AGM) and macaques. We studied them in healthy animals and during viral (SIV) infection. We performed phenotypic and transcriptomic analysis at different stages of infection. In addition, we compared CD32+CD4+ T cells in tissues with well-controlled (spleen) and not efficiently controlled (jejunum) SIV replication in AGM. The CD32+CD4+ T cells more frequently expressed markers associated with T cell activation and HIV infection (CCR5, PD-1, CXCR5, CXCR3) and had higher levels of actively transcribed SIV RNA than CD32-CD4+T cells. Furthermore, CD32+CD4+ T cells from lymphoid tissues strongly expressed B-cell-related transcriptomic signatures, and displayed B cell markers at the cell surface, including immunoglobulins CD32+CD4+ T cells were rare in healthy animals and blood but increased strongly in tissues with ongoing viral replication. CD32+CD4+ T cell levels in tissues correlated with viremia. Our results suggest that the tissue environment induced by SIV replication drives the accumulation of these unusual cells with enhanced susceptibility to viral infection.

Download Full-text