scholarly journals TLR7 trafficking and signaling in B cells is regulated by the MHCII-associated invariant chain

2020 ◽  
Vol 133 (5) ◽  
pp. jcs236711
Author(s):  
Mira Tohme ◽  
Lucie Maisonneuve ◽  
Karim Achour ◽  
Michaël Dussiot ◽  
Sophia Maschalidi ◽  
...  
Keyword(s):  
B Cells ◽  
Invariant Chain

scholarly journals Both IFN-γ and IL-4 Induce MHC Class II Expression at the Surface of Mouse Pro-B Cells

1997 ◽  
Vol 5 (2) ◽  
pp. 115-120 ◽  
Author(s):  
Suzanne Lombard-Platet ◽  
Valerie Meyer ◽  
Rhodri Ceredig
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Invariant Chain ◽  
B Cell Differentiation ◽  
Cell Clones ◽  
Ifn Γ ◽  
B Lymphoid ◽  
Mhc Class Ii Molecules

Pro-B cells are early B-cell progenitors that retain macrophage potential. We have studied MHC class II molecules and invariant chain inducibility on four class II negative mouse pro- B-cell clones. We analyzed the effects of IL-4 and IFN-γ, which represent the major inducers of class II in the B-lymphoid and monocytic/macrophage lineages, respectively. After 48 h of treatment with either cytokine, three pro-B-cell clones (C2.13, A1.5, and F2.2) expressed intracellular invariant chain and cell-surface class II molecules. One clone (D2.1) remained negative. As already reported, more differentiated 70Z/3 pre-B cells were inducible by IL-4 only. These data suggest that the induction of class II and invariant-chain genes are subject to regulation throughout B-cell differentiation.

Invariant chain processing is independent of cathepsin variation between primary human B cells/dendritic cells and B-lymphoblastoid cells

2011 ◽  
Vol 269 (2) ◽  
pp. 96-103 ◽  
Author(s):  
Michael Reich ◽  
Fang Zou ◽  
Marcin Sieńczyk ◽  
Jozef Oleksyszyn ◽  
Bernhard O. Boehm ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
B Cells ◽  
Invariant Chain ◽  
Lymphoblastoid Cells ◽  
Human B Cells

scholarly journals Major Histocompatibility Complex Class II Compartments in Human and Mouse B Lymphoblasts Represent Conventional Endocytic Compartments

1997 ◽  
Vol 139 (3) ◽  
pp. 639-649 ◽  
Author(s):  
Monique J. Kleijmeer ◽  
Stanislaw Morkowski ◽  
Janice M. Griffith ◽  
Alexander Y. Rudensky ◽  
Hans J. Geuze
Keyword(s):  
Major Histocompatibility Complex ◽  
B Cells ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Invariant Chain ◽  
Histocompatibility Complex ◽  
Peptide Complexes ◽  
Endocytic Compartments ◽  
Human And Mouse ◽  
Mhc Class Ii Molecules

In most human and mouse antigen-presenting cells, the majority of intracellular major histocompatibility complex (MHC) class II molecules resides in late endocytic MHC class II compartments (MIICs), thought to function in antigen processing and peptide loading. However, in mouse A20 B cells, early endocytic class II-containing vesicles (CIIVs) have been reported to contain most of the intracellular MHC class II molecules and have also been implicated in formation of MHC class II–peptide complexes. To address this discrepancy, we have studied in great detail the endocytic pathways of both a human (6H5.DM) and a mouse (A20.Ab) B cell line. Using quantitative immunoelectron microscopy on cryosections of cells that had been pulse–chased with transferrin-HRP or BSA-gold as endocytic tracers, we have identified up to six endocytic subcompartments including an early MIIC type enriched in invariant chain, suggesting that it serves as an important entrance to the endocytic pathway for newly synthesized MHC class II/invariant chain complexes. In addition, early MIICs represented the earliest endocytic compartment containing MHC class II– peptide complexes, as shown by using an antibody against an abundant endogenous class II–peptide complex. The early MIIC exhibited several though not all of the characteristics reported for the CIIV and was situated just downstream of early endosomes. We have not encountered any special class II-containing endocytic structures besides those normally present in nonantigen-presenting cells. Our results therefore suggest that B cells use conventional endocytic compartments rather than having developed a unique compartment to accomplish MHC class II presentation.

Invariant chain is a new chaperone for TLR7 in B cells

2015 ◽  
Vol 68 (2) ◽  
pp. 102-105 ◽  
Author(s):  
Mira Tohmé ◽  
Bénédicte Manoury
Keyword(s):  
B Cells ◽  
Invariant Chain

scholarly journals The intramembrane protease SPPL2a promotes B cell development and controls endosomal traffic by cleavage of the invariant chain

2012 ◽  
Vol 210 (1) ◽  
pp. 41-58 ◽  
Author(s):  
Janna Schneppenheim ◽  
Ralf Dressel ◽  
Susann Hüttl ◽  
Renate Lüllmann-Rauch ◽  
Michael Engelke ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Receptor ◽  
Surface Expression ◽  
Cell Development ◽  
Significant Loss ◽  
B Cell Development ◽  
Invariant Chain ◽  
Intramembrane Proteolysis ◽  
Humoral Immune

Regulated intramembrane proteolysis is a central cellular process involved in signal transduction and membrane protein turnover. The presenilin homologue signal-peptide-peptidase-like 2a (SPPL2a) has been implicated in the cleavage of type 2 transmembrane proteins. We show that the invariant chain (li, CD74) of the major histocompatability class II complex (MHCII) undergoes intramembrane proteolysis mediated by SPPL2a. B lymphocytes of SPPL2a−/− mice accumulate an N-terminal fragment (NTF) of CD74, which severely impairs membrane traffic within the endocytic system and leads to an altered response to B cell receptor stimulation, reduced BAFF-R surface expression, and accumulation of MHCII in transitional developmental stage T1 B cells. This results in significant loss of B cell subsets beyond the T1 stage and disrupted humoral immune responses, which can be recovered by additional ablation of CD74. Hence, we provide evidence that regulation of CD74-NTF levels by SPPL2a is indispensable for B cell development and function by maintaining trafficking and integrity of MHCII-containing endosomes, highlighting SPPL2a as a promising pharmacological target for depleting and/or modulating B cells.

scholarly journals The p35 human invariant chain in transgenic mice restores mature B cells in the absence of endogenous CD74

2012 ◽  
Vol 24 (10) ◽  
pp. 645-660 ◽  
Author(s):  
L. Geneve ◽  
C. Menard ◽  
N. Labrecque ◽  
J. Thibodeau
Keyword(s):  
B Cells ◽  
Transgenic Mice ◽  
Invariant Chain

scholarly journals Correction: TLR7 trafficking and signaling in B cells is regulated by the MHCII-associated invariant chain

2021 ◽  
Vol 134 (20) ◽  
Author(s):  
Mira Tohme ◽  
Lucie Maisonneuve ◽  
Karim Achour ◽  
Michaël Dussiot ◽  
Sophia Maschalidi ◽  
...  
Keyword(s):  
B Cells ◽  
Invariant Chain

Actin microfilaments control the MHC class II antigen presentation pathway in B cells

1998 ◽  
Vol 111 (13) ◽  
pp. 1791-1800 ◽  
Author(s):  
N. Barois ◽  
F. Forquet ◽  
J. Davoust
Keyword(s):  
B Cells ◽  
Actin Cytoskeleton ◽  
Mhc Class Ii ◽  
Proteolytic Enzymes ◽  
Class Ii ◽  
Invariant Chain ◽  
Chain Complexes ◽  
Presentation Pathway ◽  
Antigen Peptide ◽  
Stable Forms

Newly synthesised major histocompatibility complex class II molecules associate with invariant chains (Ii) to form nonameric complexes. These complexes are transported to endosomes, where proteolytic enzymes generate alphabeta class II dimers associated with nested Ii-derived peptides. These peptides are then exchanged with antigen peptide, and mature class II molecules reach the cell surface. The role of the actin cytoskeleton in the transport and maturation of class II molecules has not been studied. We show here that upon treatment with cytochalasin D (cyto D), the rate of Ii degradation is drastically reduced in B cells. Cyto D treatment also leads to a delayed appearance of stable forms of class II molecules, and a reduced presentation efficiency of antigen determinants requiring newly synthesised class II molecules. Under such conditions, we found that invariant chain fragments and class II molecules are accumulated in early and late endosomal compartments, whereas the leupeptin protease inhibitor induces their accumulation in lysosomal compartments. The addition of cyto D to leupeptin blocks the delivery of class II/invariant chain complexes to lysosomes, and further inhibits degradation of Ii. The dynamics of the actin cytoskeleton can therefore control the meeting point between newly synthesised class II molecules and lysosomal proteases, involved in Ii degradation and antigen peptide loading.

scholarly journals Dynamics of Major Histocompatibility Complex Class II Compartments during B Cell Receptor–mediated Cell Activation

2002 ◽  
Vol 195 (4) ◽  
pp. 461-472 ◽  
Author(s):  
Danielle Lankar ◽  
Hélène Vincent-Schneider ◽  
Volker Briken ◽  
Takeaki Yokozeki ◽  
Graça Raposo ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mhc Class Ii ◽  
Cell Receptor ◽  
Class Ii ◽  
B Cell Receptor ◽  
Cathepsin S ◽  
Invariant Chain ◽  
Histocompatibility Complex ◽  
Mhc Class Ii Molecules

Antigen recognition by clonotypic B cell receptor (BcR) is the first step of B lymphocytes differentiation into plasmocytes. This B cell function is dependent on efficient major histocompatibility complex (MHC) class II–restricted presentation of BcR-bound antigens. In this work, we analyzed the subcellular mechanisms underlying antigen presentation after BcR engagement on B cells. In quiescent B cells, we found that MHC class II molecules mostly accumulated at the cell surface and in an intracellular pool of tubulovesicular structures, whereas H2-M molecules were mostly detected in distinct lysosomal compartments devoid of MHC class II. BcR stimulation induced the transient intracellular accumulation of MHC class II molecules in newly formed multivesicular bodies (MVBs), to which H2-M was recruited. The reversible downregulation of cathepsin S activity led to the transient accumulation of invariant chain–MHC class II complexes in MVBs. A few hours after BcR engagement, cathepsin S activity increased, the p10 invariant chain disappeared, and MHC class II–peptide complexes arrived at the plasma membrane. Thus, BcR engagement induced the transient formation of antigen-processing compartments, enabling antigen-specific B cells to become effective antigen-presenting cells.

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