scholarly journals The soluble pattern recognition receptor PTX3 links humoral innate and adaptive immune responses by helping marginal zone B cells

2016 ◽  
Vol 213 (10) ◽  
pp. 2167-2185 ◽  
Author(s):  
Alejo Chorny ◽  
Sandra Casas-Recasens ◽  
Jordi Sintes ◽  
Meimei Shan ◽  
Nadia Polentarutti ◽  
...  

Pentraxin 3 (PTX3) is a fluid-phase pattern recognition receptor of the humoral innate immune system with ancestral antibody-like properties but unknown antibody-inducing function. In this study, we found binding of PTX3 to splenic marginal zone (MZ) B cells, an innate-like subset of antibody-producing lymphocytes strategically positioned at the interface between the circulation and the adaptive immune system. PTX3 was released by a subset of neutrophils that surrounded the splenic MZ and expressed an immune activation–related gene signature distinct from that of circulating neutrophils. Binding of PTX3 promoted homeostatic production of IgM and class-switched IgG antibodies to microbial capsular polysaccharides, which decreased in PTX3-deficient mice and humans. In addition, PTX3 increased IgM and IgG production after infection with blood-borne encapsulated bacteria or immunization with bacterial carbohydrates. This immunogenic effect stemmed from the activation of MZ B cells through a neutrophil-regulated pathway that elicited class switching and plasmablast expansion via a combination of T cell–independent and T cell–dependent signals. Thus, PTX3 may bridge the humoral arms of the innate and adaptive immune systems by serving as an endogenous adjuvant for MZ B cells. This property could be harnessed to develop more effective vaccines against encapsulated pathogens.

Blood ◽  
2021 ◽  
Author(s):  
Patricia E Zerra ◽  
Seema R Patel ◽  
Ryan Philip Jajosky ◽  
Connie M Arthur ◽  
James W McCoy ◽  
...  

Red blood cell (RBC) transfusions can result in alloimmunization toward RBC alloantigens that can increase the probability of complications following subsequent transfusion. An improved understanding of the immune mechanisms that underlie RBC alloimmunization is critical if future strategies capable of preventing or even reducing this process are to be realized. Using the HOD (hen egg lysozyme and ovalbumin fused to human Duffy) model system, we aimed to identify initiating immune factors that may govern early anti-HOD alloantibody formation. Our findings demonstrate that HOD RBCs continuously localize to the marginal sinus following transfusion, where they co-localize with marginal zone (MZ) B cells. Depletion of MZ B cells inhibited IgM and IgG anti-HOD antibody formation, while CD4 T cell depletion only prevented IgG anti-HOD antibody development. HOD-specific CD4 T cells displayed similar proliferation and activation following transfusion of HOD RBCs into wild type or MZ B cell deficient recipients, suggesting that IgG formation is not dependent on MZ B cell-mediated CD4 T cell activation. Moreover, depletion of follicular B cells failed to substantially impact the anti-HOD antibody response and no increase in antigen specific germinal center B cells was detected following HOD RBC transfusion, suggesting that antibody formation is not dependent on the splenic follicle. Despite this, anti-HOD antibodies persisted for several months following HOD RBC transfusion. Overall, these data suggest MZ B cells can initiate and then contribute to RBC alloantibody formation, highlighting a unique immune pathway that can be engaged following RBC transfusion.


2009 ◽  
Vol 183 (1) ◽  
pp. 518-523 ◽  
Author(s):  
Heath M. Guay ◽  
Rabinarayan Mishra ◽  
Robert L. Garcea ◽  
Raymond M. Welsh ◽  
Eva Szomolanyi-Tsuda

2014 ◽  
Vol 193 (1) ◽  
pp. 379-390 ◽  
Author(s):  
Chuang Chen ◽  
Haoting Hsu ◽  
Edward Hudgens ◽  
Janice C. Telfer ◽  
Cynthia L. Baldwin

2006 ◽  
Vol 203 (8) ◽  
pp. 1985-1998 ◽  
Author(s):  
Laura Mandik-Nayak ◽  
Jennifer Racz ◽  
Barry P. Sleckman ◽  
Paul M. Allen

In K/BxN mice, arthritis is induced by autoantibodies against glucose-6-phosphate-isomerase (GPI). To investigate B cell tolerance to GPI in nonautoimmune mice, we increased the GPI-reactive B cell frequency using a low affinity anti-GPI H chain transgene. Surprisingly, anti-GPI B cells were not tolerant to this ubiquitously expressed and circulating autoantigen. Instead, they were found in two functionally distinct compartments: an activated population in the splenic marginal zone (MZ) and an antigenically ignorant one in the recirculating follicular/lymph node (LN) pool. This difference in activation was due to increased autoantigen availability in the MZ. Importantly, the LN anti-GPI B cells remained functionally competent and could be induced to secrete autoantibodies in response to cognate T cell help in vitro and in vivo. Therefore, our study of low affinity autoreactive B cells reveals two distinct but potentially concurrent mechanisms for their activation, of which one is T cell dependent and the other is T cell independent.


2018 ◽  
Vol 36 (5_suppl) ◽  
pp. 123-123 ◽  
Author(s):  
Mark Aleynick ◽  
Paul Peng ◽  
Linda Hammerich ◽  
Ranjan Upadhyay ◽  
Netonia Marshall ◽  
...  

123 Background: In patients with low-grade lymphoma, in situ vaccination has yielded both partial and complete remissions in clinical trials. Though clinical responses have been observed with multiple pattern recognition receptor agonists (PRRa), the optimal immune stimulant is unknown. We hypothesize that natural PRRa, such as the attenuated pathogens or subunits found in common prophylactic vaccines, could target multiple PRR in a physiologically relevant context and lead to a more robust activation of dendritic cells (DCs) versus synthetic PRRa. Methods: 20 vaccines, including BCG, Typhim Vi, MMR-II, etc. were screened in vitro, where DC phenotype and function were evaluated by flow cytometry. Flt3L-mobilized DC ability to phagocytose, process, present, and cross-present soluble protein or tumor derived antigen, were assessed using CRISPR gene-edited, β2m(-/-) GFP-lymphoma cells and a novel GFP-specific (‘JEDI’) CD8 T cell system. Vaccine mechanism of immune activation was elucidated using a library of PRR-null macrophage cell lines. Potent vaccines were also evaluated in vivo in a Flt3L-primed in situ vaccination using the A20 murine lymphoma model. Results: Several vaccines induced robust DC activation and several showed significant increases in subsequent T cell activation, proliferation, and tumor killing, suggesting increased antigen processing and cross-presentation by DCs. Some vaccines, either as single agents or in combination, were significantly more effective than synthetic PRRa in activating DCs and inducing a T cell response. In vivo, vaccine combination therapies induced tumor regression in a majority of animals, suggesting synergistic immune activation. Conclusions: This data suggests prophylactic vaccines are effective clinical-grade DC activators and can be repurposed for use in the in situ vaccination maneuver, with immediate translation into the clinic. Additionally, by extensive in vitro evaluation in parallel with in vivo studies, this work aims to identify a predictive in vitro molecular immune signature that correlates closely with adjuvant efficacy in vivo.


Blood ◽  
2005 ◽  
Vol 105 (3) ◽  
pp. 1288-1294 ◽  
Author(s):  
Sang-Moo Kang ◽  
Maria Grazia Narducci ◽  
Cristina Lazzeri ◽  
Adriana M. Mongiovì ◽  
Elisabetta Caprini ◽  
...  

AbstractTCL1, the overexpression of which may result in T-cell leukemia, is normally expressed in early embryonic tissues, the ovary, and lymphoid lineage cells. Our analysis of mouse B-lineage cells indicates that Tcl1 expression is initiated in pro-B cells and persists in splenic marginal zone and follicular B cells. T-lineage Tcl1 expression begins in thymocyte progenitors, continues in CD4+CD8+ thymocytes, and is extinguished in mature T cells. In Tcl1-deficient mice, we found B lymphopoiesis to be compromised at the pre-B cell stage and T-cell lymphopoiesis to be impaired at the CD4+CD8+ thymocyte stage. A corresponding increase was observed in thymocyte susceptibility to anti-CD3ϵ–induced apoptosis. Reduced numbers of splenic follicular and germinal center B cells were accompanied by impaired production of immunoglobulin G1 (IgG1) and IgG2b antibodies in response to a T-dependent antigen. The marginal zone B cells and T-cell–independent antibody responses were also diminished in Tcl1-/- mice. This analysis indicates a significant role for Tcl1, a coactivator of Akt signaling, in normal T- and B-cell development and function.


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