scholarly journals Targeting human langerin promotes HIV-1 specific humoral immune responses

2021 ◽  
Vol 17 (7) ◽  
pp. e1009749
Author(s):  
Jérôme Kervevan ◽  
Aurélie Bouteau ◽  
Juliane S. Lanza ◽  
Adele Hammoudi ◽  
Sandra Zurawski ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Serum Levels ◽  
Target Antigen ◽  
Humoral Immune ◽  
Cell Functions ◽  
Tfh Cells ◽  
Specific Igg ◽  
Hiv 1

The main avenue for the development of an HIV-1 vaccine remains the induction of protective antibodies. A rationale approach is to target antigen to specific receptors on dendritic cells (DC) via fused monoclonal antibodies (mAb). In mouse and non-human primate models, targeting of skin Langerhans cells (LC) with anti-Langerin mAbs fused with HIV-1 Gag antigen drives antigen-specific humoral responses. The development of these immunization strategies in humans requires a better understanding of early immune events driven by human LC. We therefore produced anti-Langerin mAbs fused with the HIV-1 gp140z Envelope (αLC.Env). First, we show that primary skin human LC and in vitro differentiated LC induce differentiation and expansion of naïve CD4+ T cells into T follicular helper (Tfh) cells. Second, when human LC are pre-treated with αLC.Env, differentiated Tfh cells significantly promote the production of specific IgG by B cells. Strikingly, HIV-Env-specific Ig are secreted by HIV-specific memory B cells. Consistently, we found that receptors and cytokines involved in Tfh differentiation and B cell functions are upregulated by LC during their maturation and after targeting Langerin. Finally, we show that subcutaneous immunization of mice by αLC.Env induces germinal center (GC) reaction in draining lymph nodes with higher numbers of Tfh cells, Env-specific B cells, as well as specific IgG serum levels compared to mice immunized with the non-targeting Env antigen. Altogether, we provide evidence that human LC properly targeted may be licensed to efficiently induce Tfh cell and B cell responses in GC.

scholarly journals Monoclonal antibodies to the 140,000 mol wt glycoprotein of B lymphocyte membranes (CR2 receptor) initiates proliferation of B cells in vitro

Blood ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 824-829
Author(s):  
BS Wilson ◽  
JL Platt ◽  
NE Kay
Keyword(s):  
Monoclonal Antibodies ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
B Lymphocyte ◽  
Human Peripheral Blood ◽  
Raji Cell ◽  
Lymphoid Cells ◽  
Humoral Immune

Several mouse monoclonal IgG antibodies (AB1, AB2, AB3, and AB5) were developed that reacted with a 140,000 mol wt glycoprotein on the surface of cultured RAJI B lymphoid cells. The antibodies reacted with purified normal human peripheral blood B cells and CLL Ig+ B cells and showed specific germinal center and mantle zone staining in tissue sections of secondary lymphoid organs. Immunodepletion studies using 125I surface-labeled Raji cell membrane antigens demonstrated that the antigen identified by AB5 is the same 140,000 mol wt glycoprotein detected by anti-B2 that has recently been shown to react with the C3d fragment or CR2 receptor. (Iida et al: J Exp Med 158:1021, 1983). Addition of the AB series and anti-B2 monoclonal antibodies to cultures of purified human peripheral blood B cells resulted in the uptake of 3H- thymidine at two to six times background control levels provided that irradiated autologous T cells were added to the culture. Stimulation was not evoked by other monoclonal antibodies to B cell surface molecules (ie, B1, BA-1, BA-2, and HLA-DR). Pepsin-generated F(ab')2 fragments of anti-CR2 antibodies were essentially as effective as the intact IgG molecule in stimulating B cells. Induction of B cell proliferation by antibody binding to CR2 suggests that the C3d receptor may have an integral role in regulation of humoral immune response.

scholarly journals Lymphocyte interleukin 2 production and responsiveness are altered in patients with primary myelodysplastic syndrome

Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 494-500
Author(s):  
O Ayanlar-Batuman ◽  
J Shevitz ◽  
UC Traub ◽  
S Murphy ◽  
D Sajewski
Keyword(s):  
T Cells ◽  
B Cells ◽  
Myelodysplastic Syndrome ◽  
B Cell ◽  
Interleukin 2 ◽  
T Cell Proliferation ◽  
Cell Functions ◽  
Normal Limits ◽  
Stimulatory Capacity

Immunoregulatory T and B cell functions in 15 patients with primary myelodysplastic syndrome (MDS) were studied by measuring the proliferative and the stimulatory capacity of T and B cells, respectively, in autologous (auto) and allogeneic (allo) mixed lymphocyte reaction (MLR). T cell proliferation in the auto MLR was 25% of the control (P less than .02), whereas proliferation in the allo MLR was normal. When control T cells were stimulated by MDS B cells, their proliferative response was only 57% of the control (P less than .01). The mechanism responsible for these abnormalities was studied by determining the capacity of MDS and normal T cells to produce interleukin 2 (IL 2) and to generate IL 2 receptors (IL 2R) following stimulation with control and MDS B cells. In the auto MLR of MDS patients, only 3% +/- 2% of T cells developed IL 2R positivity, whereas in control cultures 12% +/- 2% of T cells were positive, as determined by immunofluorescence, using a monoclonal antibody (MoAb) directed against the IL 2R, and FACS analysis. When MDS T cells were stimulated by control B cells, IL 2R generation and the production of IL 2 were within normal limits. In contrast, when control T cells were stimulated by MDS B cells or control B cells, the MDS B cells induced production of only 26% of IL 2 as compared with control B cells. In parallel experiments, IL 2R generation in control T cells stimulated by either MDS or control B cells was similar. We conclude that in the primary MDS, T and B cell interactions are impaired. Although MDS T cells develop normal quantities of IL 2R and produce normal amounts of IL 2 when stimulated by control B cells, they are markedly impaired when stimulated by self B cells. Similarly, MDS B cells can induce IL 2R generation in control T cells but not in MDS T cells. Myelodysplastic B cells are also defective in inducing IL 2 production by normal T cells in an allo MLR. These in vitro abnormalities strongly suggest that generation of lymphocytes with immunoregulatory functions is impaired in patients with MDS.

scholarly journals Attenuation of Apoptosis Underlies B Lymphocyte Stimulator Enhancement of Humoral Immune Response

2000 ◽  
Vol 192 (7) ◽  
pp. 953-964 ◽  
Author(s):  
Richard K.G. Do ◽  
Eunice Hatada ◽  
Hayyoung Lee ◽  
Michelle R. Tourigny ◽  
David Hilbert ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Survival ◽  
B Lymphocyte ◽  
Humoral Immune ◽  
B Cell Survival ◽  
B Lymphocyte Stimulator

B lymphocyte stimulator (BLyS) is a newly identified monocyte-specific TNF family cytokine. It has been implicated in the development of autoimmunity, and functions as a potent costimulator with antiimmunoglobulin M in B cell proliferation in vitro. Here we demonstrate that BLyS prominently enhances the humoral responses to both T cell–independent and T cell–dependent antigens, primarily by attenuation of apoptosis as evidenced by the prolonged survival of antigen-activated B cells in vivo and in vitro. BLyS acts on primary splenic B cells autonomously, and directly cooperates with CD40 ligand (CD40L) in B cell activation in vitro by protecting replicating B cells from apoptosis. Moreover, although BLyS alone cannot activate the cell cycle, it is sufficient to prolong the survival of naive resting B cells in vitro. Attenuation of apoptosis by BLyS correlates with changes in the ratios between Bcl-2 family proteins in favor of cell survival, predominantly by reducing the proapoptotic Bak and increasing its prosurvival partners, Bcl-2 and Bcl-xL. In either resting or CD40L-activated B cells, the NF-κB transcription factors RelB and p50 are specifically activated, suggesting that they may mediate BLyS signals for B cell survival. Together, these results provide direct evidence for BLyS enhancement of both T cell–independent and T cell–dependent humoral immune responses, and imply a role for BLyS in the conservation of the B cell repertoire. The ability of BLyS to increase B cell survival indiscriminately, at either a resting or activated state, and to cooperate with CD40L, further suggests that attenuation of apoptosis underlies BLyS enhancement of polyclonal autoimmunity as well as the physiologic humoral immune response.

scholarly journals Antibody Production and In Vitro Behavior of CD27-Defined B-Cell Subsets: Persistent Hepatitis C Virus Infection Changes the Rules

2006 ◽  
Vol 80 (8) ◽  
pp. 3923-3934 ◽  
Author(s):  
Vito Racanelli ◽  
Maria Antonia Frassanito ◽  
Patrizia Leone ◽  
Maria Galiano ◽  
Valli De Re ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Feedback Inhibition ◽  
Cell Subset ◽  
Functional Program ◽  
Cell Functions

ABSTRACT There is growing interest in the tendency of B cells to change their functional program in response to overwhelming antigen loading, perhaps by regulating specific parameters, such as efficiency of activation, proliferation rate, differentiation to antibody-secreting cells (ASC), and rate of cell death in culture. We show that individuals persistently infected with hepatitis C virus (HCV) carry high levels of circulating immunoglobulin G (IgG) and IgG-secreting cells (IgG-ASC). Thus, generalized polyclonal activation of B-cell functions may be supposed. While IgGs include virus-related and unrelated antibodies, IgG-ASC do not include HCV-specific plasma cells. Despite signs of widespread activation, B cells do not accumulate and memory B cells seem to be reduced in the blood of HCV-infected individuals. This apparent discrepancy may reflect the unconventional activation kinetics and functional responsiveness of the CD27+ B-cell subset in vitro. Following stimulation with T-cell-derived signals in the absence of B-cell receptor (BCR) engagement, CD27+ B cells do not expand but rapidly differentiate to secrete Ig and then undergo apoptosis. We propose that their enhanced sensitivity to BCR-independent noncognate T-cell help maintains a constant level of nonspecific serum antibodies and ASC and serves as a backup mechanism of feedback inhibition to prevent exaggerated B-cell responses that could be the cause of significant immunopathology.

Long Term Humoral Immune Reconstitution Kinetics After Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) In Children

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4627-4627
Author(s):  
Amro Elshoury ◽  
Neena Kapoor ◽  
Ami J Shah ◽  
Bhakti Mehta ◽  
Kris M. Mahadeo ◽  
...  
Keyword(s):  
B Cells ◽  
Serum Level ◽  
B Cell ◽  
Immune Reconstitution ◽  
Serum Levels ◽  
Multivariate Regression Analysis ◽  
Memory B Cells ◽  
Post Transplantation ◽  
Humoral Immune ◽  
Cell Counts

Background HSCT recipients have increased incidence of acquiring infections, particularly by encapsulated bacteria such as Streptococcal pneumoniae and Haemophilus influenzae. Delayed immune reconstitution has a pivotal role in these complications. Although T-cell immune reconstitution has been well studied, long-term B-cell reconstitution remains less characterized. Patients and Methods We studied 73 patients, who received allogeneic HSCT at Childrens Hospital Los Angeles. Patients were in complete remission of their underlying disorder and with median follow up 4.15 years [yrs] (range 6 month -18yrs, mean 5 yrs) post-HSCT. All subjects were< 18 years of age. B (naive [IgD+CD27-CD19+], memory [IgD+CD27+CD19+] and switched memory [IgD-CD27+CD19]); and T (CD3+, CD3+CD4+, CD3+CD8+, CD4+CD25+CD127dim (T Regulatory) [Tregs], RA+CD4+) cell subtypes, quantitative Immunoglobulins levels and antibodies to both polyribosyle polyphospate (PRP) and tetanus toxoid (TT) antigens were assessed longitudinally after HSCT. Results Naive B Cells were the first B cell subtype to return to normal value at 6 month post-HSCT, while memory B cells were persistently low up to two years post-HSCT. PRP levels continued to be low up to 10 years post -HSCT in unrelated donor HSCT recipients. TT antibodies level was normal at 6 month post-HSCT following immunization with TT in patients not receiving IVIG therapy. Switched memory B cell counts correlated positively with RA+CD4+ counts at 6 month post-HSCT (r=0.459, P=0.021) and with CD3+CD+4 counts at 6 months (r=0.530, P=0.006) and 2-years post-HSCT (r=0.398, P=0.016). However, switched memory B cells did not correlate with Tregs at any time post-HSCT. Switched memory B cells correlated positively with serum level of IgG at 1 (r=0.443, P=0.039), and 2 years post transplantation (r=0.617, P=0.001) and with serum level of IgA at 2 years post-HSCT(r=0.567. P=0.004). Memory B-cells counts correlated positively with serum levels of IgM at 1 year post-HSCT (r=0.478, P=0.021) and with serum levels of both IgG and IgA (r=0.431 P=0.035, and r=0.416, P=0.043, respectively) at 2 years post-HSCT. However, memory B-cell counts did not correlate with RA+CD4+, CD3+CD4+, CD3+CD8+ or Tregs cell counts. The use of Total body irradiation (TBI) was associated with lower switched memory B cells at 2 years (P=0.01) post-HSCT. TBI recipients also have lower PRP levels at 6-month post-HSCT compared to patients who did not receive TBI. Age of the recipient at time transplantation is another independent factor affecting all the B cell subsets recovery after transplantation; increase in age at transplantation is associated with lower B cell recovery. Decreased memory B cells post-HSCT was observed in patients with history of acute graft versus host disease (GVHD) (P=0.034) and chronic GVHD (P=0.01), even after resolution of clinical manifestations of active GVHD at 6 month and 2 years follow up, respectively. Compared to cord blood graft recipients, Bone marrow graft recipients have increased switched memory B-cells at 6 month and higher (P=0.0001) PRP antibodies titer at 3 years post-HSCT, respectively. Patients who did not receive ATG or Alemtuzumab have increased recovery of naive B-cells (P=0.024) at 2 years post-transplantation. Patients received ATG have higher both naive B cells in univariate analysis and PRP levels (in multivariate analysis) than those received Alemtuzumab at 6 months post-HSCT. Multivariate regression analysis showed that patients received Alemtuzumab have higher TT antibodies titer at 6 month post -HSCT compared to those received ATG. Conclusion We have found that memory and switched memory B-cells and serum PRP levels are deficient post-HSCT in children. Switched memory B cells correlated positively with serum level of IgG and IgA and memory B-cells correlated positively with serum levels of IgM, IgG and IgA. This confirms that HSCT recipients have impaired humoral immune reconstitution, hindering both B-cells development and generation of immunoglobulins. We also studied the different factors affecting humoral immune reconstitution using backwards multivariate regression analysis model and found that the use of TBI, age of the recipient at transplantation, GVHD status and source of stem cells can affect the kinetics of humoral immune reconstitution after HSCT in children. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Covalent Linkage of HIV-1 Trimers to Synthetic Liposomes Elicits Improved B Cell and Antibody Responses

2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Shridhar Bale ◽  
Geraldine Goebrecht ◽  
Armando Stano ◽  
Richard Wilson ◽  
Takayuki Ota ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Neutralizing Antibodies ◽  
Tier 2 ◽  
Covalent Linkage ◽  
His Tag ◽  
Hiv 1

ABSTRACT We have demonstrated that a liposomal array of well-ordered trimers enhances B cell activation, germinal center formation, and the elicitation of tier-2 autologous neutralizing antibodies. Previously, we coupled well-ordered cleavage-independent NFL trimers via their C-terminal polyhistidine tails to nickel lipids integrated into the lipid bilayer. Despite favorable in vivo effects, concern remained over the potentially longer-term in vivo instability of noncovalent linkage of the trimers to the liposomes. Accordingly, we tested both cobalt coupling and covalent linkage of the trimers to the liposomes by reengineering the polyhistidine tail to include a free cysteine on each protomer of model BG505 NFL trimers to allow covalent linkage. Both cobalt and cysteine coupling resulted in a high-density array of NFL trimers that was stable in both 20% mouse serum and 100 mM EDTA, whereas the nickel-conjugated trimers were not stable under these conditions. Binding analysis and calcium flux with anti-Env-specific B cells confirmed that the trimers maintained conformational integrity following coupling. Following immunization of mice, serologic analysis demonstrated that the covalently coupled trimers elicited Env-directed antibodies in a manner statistically significantly improved compared to soluble trimers and nickel-conjugated trimers. Importantly, the covalent coupling not only enhanced gp120-directed responses compared to soluble trimers, it also completely eliminated antibodies directed to the C-terminal His tag located at the “bottom” of the spike. In contrast, soluble and noncovalent formats efficiently elicited anti-His tag antibodies. These data indicate that covalent linkage of well-ordered trimers to liposomes in high-density array displays multiple advantages in vitro and in vivo. IMPORTANCE Enveloped viruses typically encode a surface-bound glycoprotein that mediates viral entry into host cells and is a primary target for vaccine design. Liposomes with modified lipid head groups have a unique feature of capturing and displaying antigens on their surfaces, mimicking the native pathogens. Our first-generation nickel-based liposomes captured HIV-1 Env glycoprotein trimers via a noncovalent linkage with improved efficacy over soluble glycoprotein in activating germinal center B cells and eliciting tier-2 autologous neutralizing antibodies. In this study, we report the development of second-generation cobalt- and maleimide-based liposomes that have improved in vitro stability over nickel-based liposomes. In particular, the maleimide liposomes captured HIV-1 Env trimers via a more stable covalent bond, resulting in enhanced germinal center B cell responses that generated higher antibody titers than the soluble trimers and liposome-bearing trimers via noncovalent linkages. We further demonstrate that covalent coupling prevents release of the trimers prior to recognition by B cells and masks a nonneutralizing determinant located at the bottom of the trimer.

scholarly journals Monoclonal antibodies to the 140,000 mol wt glycoprotein of B lymphocyte membranes (CR2 receptor) initiates proliferation of B cells in vitro

Blood ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 824-829 ◽  
Author(s):  
BS Wilson ◽  
JL Platt ◽  
NE Kay
Keyword(s):  
Monoclonal Antibodies ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
B Lymphocyte ◽  
Human Peripheral Blood ◽  
Raji Cell ◽  
Lymphoid Cells ◽  
Humoral Immune

Abstract Several mouse monoclonal IgG antibodies (AB1, AB2, AB3, and AB5) were developed that reacted with a 140,000 mol wt glycoprotein on the surface of cultured RAJI B lymphoid cells. The antibodies reacted with purified normal human peripheral blood B cells and CLL Ig+ B cells and showed specific germinal center and mantle zone staining in tissue sections of secondary lymphoid organs. Immunodepletion studies using 125I surface-labeled Raji cell membrane antigens demonstrated that the antigen identified by AB5 is the same 140,000 mol wt glycoprotein detected by anti-B2 that has recently been shown to react with the C3d fragment or CR2 receptor. (Iida et al: J Exp Med 158:1021, 1983). Addition of the AB series and anti-B2 monoclonal antibodies to cultures of purified human peripheral blood B cells resulted in the uptake of 3H- thymidine at two to six times background control levels provided that irradiated autologous T cells were added to the culture. Stimulation was not evoked by other monoclonal antibodies to B cell surface molecules (ie, B1, BA-1, BA-2, and HLA-DR). Pepsin-generated F(ab')2 fragments of anti-CR2 antibodies were essentially as effective as the intact IgG molecule in stimulating B cells. Induction of B cell proliferation by antibody binding to CR2 suggests that the C3d receptor may have an integral role in regulation of humoral immune response.

scholarly journals The Nod2 Agonist Muramyl Dipeptide Cooperates with the TLR4 Agonist Lipopolysaccharide to Enhance IgG2b Production in Mouse B Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Sang-Hoon Lee ◽  
Jong-Hwan Park ◽  
Seok-Rae Park
Keyword(s):  
B Cells ◽  
Cell Viability ◽  
B Cell ◽  
Muramyl Dipeptide ◽  
Combined Effect ◽  
Deficient Mouse ◽  
Cell Functions ◽  
Tlr4 Agonist ◽  
Cell Mitogen

Many studies have shown that Toll-like receptors (TLRs) and Nod-like receptors (NLRs) were expressed in B cells and their signaling affects B cell functions. Nonetheless, the roles played by these receptors in B cell antibody (Ab) production have not been completely elucidated. In the present study, we examined the effect of the Nod2 agonist muramyl dipeptide (MDP) in combination with the TLR4 agonist lipopolysaccharide (LPS), a well-known B cell mitogen, on B cell viability, proliferation, and activation, and Ab production by in vitro culture of purified mouse spleen resting B cells. MDP combined with LPS to reinforce B cell viability, proliferation, and activation. Moreover, MDP enhanced LPS-induced IgG2b production, germline γ2b transcript (GLTγ2b) expression, and surface IgG2b expression. In an experiment with Nod2- and TLR4-deficient mouse B cells, we observed that the combined effect of MDP and LPS is dependent on Nod2 and TLR4 receptors. Furthermore, the combined effect on B cell viability and IgG2b switching was not observed in Rip2-deficient mouse cells. Collectively, this study suggests that Nod2 signaling enhances TLR4-activated B cell proliferation, IgG2b switching, and IgG2b production.

scholarly journals The malignant B cells from B-chronic lymphocytic leukemia patients release TAC-soluble interleukin-2 receptors

Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 447-450 ◽  
Author(s):  
NE Kay ◽  
J Burton ◽  
D Wagner ◽  
DL Nelson
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Interleukin 2 ◽  
Elevated Serum ◽  
Serum Levels ◽  
Mean Value ◽  
Lymphocytic Leukemia ◽  
Membrane Expression

Abstract Both membrane (p55) and soluble (p45) forms of TAC-reactive interleukin- 2 receptor (IL-2R) are expressed and/or released by activated lymphocytes or monocytes. Previous work has detected increased levels of circulating, TAC-soluble IL-2R (soluble TAC antigen) in the serum of most B-cell chronic lymphocytic leukemia (B-CLL) patients. We detected soluble TAC antigen in B-CLL patients (mean of 3,332 U/mL v 410 for controls). Serum soluble TAC antigen levels increased with stage (mean value of 1,187 U/mL for stage 0 v 2,527 for stage 2 and 5,410 for stages 3 and 4). We next attempted to determine whether the elevated serum levels of soluble TAC antigen in B-CLL patients might result from shedding or secretion of the receptor from the circulating, malignant B cells. Purified, malignant B cells from B-CLL patients were capable of producing easily detectable soluble TAC antigen after 48 hours of in vitro culture (range of 60 to 1,563 U/mL). IL-2R production by CLL B cells was dose dependent in most patients over a concentration of 10 x 10(6) to 60 x 10(6)/mL. In contrast, there was little or no detectable soluble TAC antigen when highly purified T cells from the same patients were cultured. Finally, despite elaboration of soluble IL-2R by CLL B cells, membrane expression of B-cell IL-2R was detected in only six of 11 patients. Thus, the cellular source of the elevated serum IL-2R levels is the malignant CLL B cell. Taken together these data suggest that (a) the malignant CLL B cell is “activated” in terms of release of soluble IL-2R and may serve as a tumor marker in this disease and (b) the elevated levels of circulating IL-2R may be an associated factor in the cellular immunodeficiency noted in B-CLL patients.

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