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Sakai J, Yang J, Chou CK, Wu WW, Akkoyunlu M. B cell receptor-induced IL-10 production from neonatal mouse CD19 +CD43 - cells depends on STAT5-mediated IL-6 secretion. eLife 2023; 12:83561. [PMID: 36735294 PMCID: PMC9934864 DOI: 10.7554/elife.83561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/31/2023] [Indexed: 02/04/2023] Open
Abstract
Newborns are unable to reach the adult-level humoral immune response partly due to the potent immunoregulatory role of IL-10. Increased IL-10 production by neonatal B cells has been attributed to the larger population of IL-10-producting CD43+ B-1 cells in neonates. Here, we show that neonatal mouse CD43- non-B-1 cells also produce substantial amounts of IL-10 following B cell antigen receptor (BCR) activation. In neonatal mouse CD43- non-B-1 cells, BCR engagement activated STAT5 under the control of phosphorylated forms of signaling molecules Syk, Btk, PKC, FAK, and Rac1. Neonatal STAT5 activation led to IL-6 production, which in turn was responsible for IL-10 production in an autocrine/paracrine fashion through the activation of STAT3. In addition to the increased IL-6 production in response to BCR stimulation, elevated expression of IL-6Rα expression in neonatal B cells rendered them highly susceptible to IL-6-mediated STAT3 phosphorylation and IL-10 production. Finally, IL-10 secreted from neonatal mouse CD43- non-B-1 cells was sufficient to inhibit TNF-α secretion by macrophages. Our results unveil a distinct mechanism of IL-6-dependent IL-10 production in BCR-stimulated neonatal CD19+CD43- B cells.
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Affiliation(s)
- Jiro Sakai
- Laboratory of Bacterial Polysaccharides, Division of Bacterial Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, The US Food and Drug AdministrationSilver SpringUnited States
| | - Jiyeon Yang
- Laboratory of Bacterial Polysaccharides, Division of Bacterial Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, The US Food and Drug AdministrationSilver SpringUnited States
| | - Chao-Kai Chou
- Facility for Biotechnology Resources, Center for Biologics Evaluation and Research, United States Food and Drug AdministrationSilver SpringUnited States
| | - Wells W Wu
- Facility for Biotechnology Resources, Center for Biologics Evaluation and Research, United States Food and Drug AdministrationSilver SpringUnited States
| | - Mustafa Akkoyunlu
- Laboratory of Bacterial Polysaccharides, Division of Bacterial Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, The US Food and Drug AdministrationSilver SpringUnited States
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Clemens EA, Alexander-Miller MA. Understanding Antibody Responses in Early Life: Baby Steps towards Developing an Effective Influenza Vaccine. Viruses 2021; 13:v13071392. [PMID: 34372597 PMCID: PMC8310046 DOI: 10.3390/v13071392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/13/2021] [Indexed: 01/01/2023] Open
Abstract
The immune system of young infants is both quantitatively and qualitatively distinct from that of adults, with diminished responsiveness leaving these individuals vulnerable to infection. Because of this, young infants suffer increased morbidity and mortality from respiratory pathogens such as influenza viruses. The impaired generation of robust and persistent antibody responses in these individuals makes overcoming this increased vulnerability through vaccination challenging. Because of this, an effective vaccine against influenza viruses in infants under 6 months is not available. Furthermore, vaccination against influenza viruses is challenging even in adults due to the high antigenic variability across viral strains, allowing immune evasion even after induction of robust immune responses. This has led to substantial interest in understanding how specific antibody responses are formed to variable and conserved components of influenza viruses, as immune responses tend to strongly favor recognition of variable epitopes. Elicitation of broadly protective antibody in young infants, therefore, requires that both the unique characteristics of young infant immunity as well as the antibody immunodominance present among epitopes be effectively addressed. Here, we review our current understanding of the antibody response in newborns and young infants and discuss recent developments in vaccination strategies that can modulate both magnitude and epitope specificity of IAV-specific antibody.
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Glaesener S, Jaenke C, Habener A, Geffers R, Hagendorff P, Witzlau K, Imelmann E, Krueger A, Meyer-Bahlburg A. Decreased production of class-switched antibodies in neonatal B cells is associated with increased expression of miR-181b. PLoS One 2018; 13:e0192230. [PMID: 29389970 PMCID: PMC5794184 DOI: 10.1371/journal.pone.0192230] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 01/18/2018] [Indexed: 01/11/2023] Open
Abstract
The increased susceptibility to infections of neonates is caused by an immaturity of the immune system as a result of both qualitative and quantitative differences between neonatal and adult immune cells. With respect to B cells, neonatal antibody responses are known to be decreased. Accountable for this is an altered composition of the neonatal B cell compartment towards more immature B cells. However, it remains unclear whether the functionality of individual neonatal B cell subsets is altered as well. In the current study we therefore compared phenotypical and functional characteristics of corresponding neonatal and adult B cell subpopulations. No phenotypic differences could be identified with the exception of higher IgM expression in neonatal B cells. Functional analysis revealed differences in proliferation, survival, and B cell receptor signaling. Most importantly, neonatal B cells showed severely impaired class-switch recombination (CSR) to IgG and IgA. This was associated with increased expression of miR-181b in neonatal B cells. Deficiency of miR-181b resulted in increased CSR. With this, our results highlight intrinsic differences that contribute to weaker B cell antibody responses in newborns.
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Affiliation(s)
- Stephanie Glaesener
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany
| | - Christine Jaenke
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany
| | - Anika Habener
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
| | - Robert Geffers
- Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Hagendorff
- Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Katrin Witzlau
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Esther Imelmann
- Institute for Molecular Medicine, Goethe University, Frankfurt am Main, Germany
| | - Andreas Krueger
- Institute of Immunology, Hannover Medical School, Hannover, Germany
- Institute for Molecular Medicine, Goethe University, Frankfurt am Main, Germany
| | - Almut Meyer-Bahlburg
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
- * E-mail:
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Pasman Y, Merico D, Kaushik AK. Preferential expression of IGHV and IGHD encoding antibodies with exceptionally long CDR3H and a rapid global shift in transcriptome characterizes development of bovine neonatal immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 67:495-507. [PMID: 27601209 DOI: 10.1016/j.dci.2016.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 08/31/2016] [Indexed: 06/06/2023]
Abstract
With an objective to understand natural development of bovine neonatal immunity, we analyzed 18 RNA-seq libraries from peripheral blood lymphocytes of three neonatal calves pre- (day 0) and post-colostrum (7, 14 and 28) uptake as compared to their dams. A significant global shift in neonatal transcriptome occurs within first week post-birth, in contrast to dams, with an upregulation of 717 genes. Global pathway analysis of the transcriptome revealed 110 differentially expressed immune-related genes, such as, complement, MHCII, chemokine receptors, defensins and cytokines, at birth. The signaling molecules (LAX1, BLK) and transcription factors (GATA3, FOXP3) are expressed at high levels. High expression of GATA3 transcription factor at birth seems to skew the neonatal immune response towards TH2 type. The high levels of T-cell signaling molecules, CD3G and CD3D, at birth are important in neonatal T cell development. Unlike adults, IGKC expression is high in the neonates where IGKV12 is preferentially expressed at birth. But IGLC is predominant in both neonates and adult where IGLV3.4 is preferentially expressed in B cells at birth. Both IGHM and IGHD are expressed at birth and IGHM achieves adult levels by day 7. This is followed by IGHA and IGHG expression 14-28 days post-birth. Importantly, preferential expression of IGHV1S1(BF4E9) and longest IGHD2(DH2) genes that encode immunoglobulin with exceptionally long CDR3H at birth indicates their critical role, as B cell antigen receptor, in the B cell development via idiotype-anti-idiotype interactions. The transcriptome signatures described here permit assessment bovine neonatal immunocompetence. Bovine neonates acquire innate and IgM-mediated humoral immunocompetence within first week post-birth.
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Affiliation(s)
- Yfke Pasman
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Daniele Merico
- The Centre for Applied Genomics, Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Azad K Kaushik
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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Vaccination of neonates: Problem and issues. Vaccine 2012; 30:1541-59. [DOI: 10.1016/j.vaccine.2011.12.047] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 11/30/2011] [Accepted: 12/08/2011] [Indexed: 12/21/2022]
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Expression of complement receptor 2 (CD21), membrane IgM and the inhibitory receptor CD32 (FcgammaRIIb) in the lymphoid tissues of neonatal calves. Vet Immunol Immunopathol 2010; 137:99-108. [PMID: 20488561 DOI: 10.1016/j.vetimm.2010.04.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 04/14/2010] [Accepted: 04/23/2010] [Indexed: 12/28/2022]
Abstract
Limited active antibody responses in neonates following vaccination have been attributed to immaturity of the immune system and to the suppressive effects of maternal antibodies. The activating receptor CD21 (CR2), when co-ligated with membrane IgM (mIgM) by complement-bound antigen lowers the threshold for activation of B lymphocytes. The inhibitory receptor CD32 (FcgammaRII) when co-ligated with mIgM by antigen-antibody complexes raises the threshold for activation. Expression of these receptors, which potentially play roles in regulation of B cell responses in the presence of maternal antibodies in neonates, has been recently characterized in blood lymphocytes in neonatal calves. Little is known however about expression of these receptors in the lymphoid tissues, where immune responses are initiated. In this study, expression of CD21, mIgM and CD32 receptors by B lymphocytes was studied in a range of lymphoid tissues including spleen, lymph nodes and bone marrow from newborn and 7-week-old calves using flow cytometry. The proportion of naïve B lymphocytes in the lymphocyte gate was significantly lower in blood and spleen of newborn calves compared to 7-week-old calves. Over 90% of B lymphocytes expressed CD21 in the lymphoid tissues. In the lymph nodes and spleen, a lower proportion of mIgM(+) B lymphocytes expressed CD32 compared to blood. In addition, intensity of expression of CD32 on B cells in lymph nodes was significantly lower compared to that in blood, suggesting a lower potential for inhibitory signalling in B cells in the lymphoid microenvironment. Investigation of the CD5(+) B cell population (as an indicator of B1 B cells) suggested an increase in the proportion of IgM(+)CD5(+) cells with age in calves, in both blood and lymphoid tissue, in contrast to the situation in humans and mice. Overall, the majority of naïve B lymphocytes in lymphoid tissues in neonatal calves expressed both activating (CD21, mIgM) and inhibitory (CD32) receptors. These receptors may provide targets for novel adjuvants, to lower the threshold for activation of B cells in neonates, and enhance antibody responses.
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7
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Chattha KS, Firth MA, Hodgins DC, Shewen PE. Variation in expression of membrane IgM, CD21 (CR2) and CD32 (Fcgamma RIIB) on bovine lymphocytes with age: a longitudinal study. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:510-517. [PMID: 20036278 DOI: 10.1016/j.dci.2009.12.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 12/17/2009] [Accepted: 12/17/2009] [Indexed: 05/28/2023]
Abstract
Typically, neonatal calves have poor active antibody responses to vaccination, attributed to immaturity of the neonatal immune system and suppressive effects of maternal (colostral) antibodies. Responses of naïve B cells are regulated by ligation of opposing activating (CD21, membrane IgM [mIgM]) and inhibitory (CD32) receptors. Expression of these receptors on blood lymphocytes of 15 calves, from birth to 6 months of age, was investigated by three-colour flow cytometry. Although the absolute number of mIgM(+) B lymphocytes was low in calves under 6 weeks, the intensity of mIgM expression per cell was significantly higher than for adults and >90% expressed both CD21 and CD32. The intensity of CD21 expression in calves did not differ significantly from adults, whereas CD32 expression was lower. Paradoxically, these findings suggest that responses of neonates should bias toward activation at the B cell level, warranting further investigation to reveal strategies for development of vaccines that are efficacious at an early age.
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Affiliation(s)
- Kuldeep S Chattha
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, Ontario, Canada
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8
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Madsen-Bouterse SA, Romero R, Tarca AL, Kusanovic JP, Espinoza J, Kim CJ, Kim JS, Edwin SS, Gomez R, Draghici S. The transcriptome of the fetal inflammatory response syndrome. Am J Reprod Immunol 2010; 63:73-92. [PMID: 20059468 PMCID: PMC3437779 DOI: 10.1111/j.1600-0897.2009.00791.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PROBLEM The fetal inflammatory response syndrome (FIRS) is considered the counterpart of the systemic inflammatory response syndrome (SIRS), but similarities in their regulatory mechanisms are unclear. This study characterizes the fetal mRNA transcriptome of peripheral leukocytes to identify key biological processes and pathways involved in FIRS. METHOD OF STUDY Umbilical cord blood from preterm neonates with FIRS (funisitis, plasma IL-6 >11 pg/mL; n = 10) and neonates with no evidence of inflammation (n = 10) was collected at birth. Results Microarray analysis of leukocyte RNA revealed differential expression of 541 unique genes, changes confirmed by qRT-PCR for 41 or 44 genes tested. Similar to SIRS and sepsis, ontological and pathway analyses yielded significant enrichment of biological processes including antigen processing and presentation, immune response, and processes critical to cellular metabolism. RESULTS are comparable with microarray studies of endotoxin challenge models and pediatric sepsis, identifying 25 genes across all studies. CONCLUSION This study is the first to profile genome-wide expression in FIRS, which demonstrates a substantial degree of similarity with SIRS despite differences in fetal and adult immune systems.
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Affiliation(s)
| | - Roberto Romero
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
- Wayne State University/Hutzel Women’s Hospital, Department of Obstetrics and Gynecology, Detroit, Michigan, USA
- Wayne State University, Center for Molecular Medicine and Genetics, Detroit, Michigan, USA
| | - Adi L. Tarca
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
- Wayne State University, Department of Computer Science, Detroit, Michigan, USA
| | - Juan Pedro. Kusanovic
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
- Wayne State University/Hutzel Women’s Hospital, Department of Obstetrics and Gynecology, Detroit, Michigan, USA
| | - Jimmy Espinoza
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
- Wayne State University/Hutzel Women’s Hospital, Department of Obstetrics and Gynecology, Detroit, Michigan, USA
| | - Chong Jai Kim
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
- Wayne State University, Department of Pathology, Wayne State University, Detroit, MI, USA
| | - Jung-Sun Kim
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
- Wayne State University, Department of Pathology, Wayne State University, Detroit, MI, USA
| | - Samuel S. Edwin
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan, USA
| | - Ricardo Gomez
- CEDIP (Center for Perinatal Diagnosis and Research), Department of Obstetrics and Gynecology, Sotero del Rio Hospital, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Sorin Draghici
- Wayne State University, Department of Computer Science, Detroit, Michigan, USA
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Chattha KS, Firth MA, Hodgins DC, Shewen PE. Age related variation in expression of CD21 and CD32 on bovine lymphocytes: A cross-sectional study. Vet Immunol Immunopathol 2009; 130:70-8. [DOI: 10.1016/j.vetimm.2009.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 01/19/2009] [Accepted: 01/26/2009] [Indexed: 12/31/2022]
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Tasker L, Marshall-Clarke S. Functional responses of human neonatal B lymphocytes to antigen receptor cross-linking and CpG DNA. Clin Exp Immunol 2004; 134:409-19. [PMID: 14632745 PMCID: PMC1808896 DOI: 10.1111/j.1365-2249.2003.02318.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Human neonates are immunologically immature and consequently are highly susceptible to infection. The cellular basis for the dysfunctional immune responses of neonates is not clear, but is likely to reflect the immaturity of both B and T cell populations. Here we have examined the ability of human cord blood B cells to respond to antigen receptor cross-linking and also to CpG containing oligodeoxynucleotides (ODN), and compared their responses with those of adult peripheral blood B cells. Antigen receptor cross-linking with soluble F(ab')2 anti-IgM antibodies, induced HLA-DR and CD86 up-regulation and proliferation to a similar extent in adult and cord blood B cells. Both interleukin (IL)-2 and IL-4 co-stimulated anti-IgM-induced proliferation, but cord blood B cells were less sensitive than adult B cells to the co-stimulatory effects of IL-2. Antigen receptor cross-linking induced secretion of the chemokines macrophage inflammatory protein-1 alpha (MIP-1 alpha) and MIP-1 beta in adult and cord blood B cells, and secretion was enhanced by IL-2 or IL-4. CpG-ODN induced up-regulation of HLA-DR and CD86 expression and proliferation of adult and cord blood B cells, and anti-IgM and CPG-ODN synergized in the induction of proliferation. CpG-ODN also induced MIP-1 alpha and MIP-1 alpha secretion in adult and cord blood B cells. In addition to functional studies we examined the expression of CD62L (l-selectin), CCR7 and CXCR5. Our data show that surface expression of CD62L and CCR7 is lower on cord blood B cells than on adult B cells, suggesting that human cord blood B cells may exhibit homing defects.
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Affiliation(s)
- L Tasker
- Department of Human Anatomy and Cell Biology, The University of Liverpool, Liverpool, UK
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Macardle PJ, Mardell C, Bailey S, Wheatland L, Ho A, Jessup C, Roberton DM, Zola H. FcgammaRIIb expression on human germinal center B lymphocytes. Eur J Immunol 2002; 32:3736-44. [PMID: 12516568 DOI: 10.1002/1521-4141(200212)32:12<3736::aid-immu3736>3.0.co;2-i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
IgG antibody can specifically suppress the antibody response to antigen. This has been explained by the hypothesis that signaling through the B cell antigen receptor is negatively modulated by the co-ligation of immunoglobulin with the receptor for IgG, FcgammaRIIb. We hypothesized that inhibitory signaling through FcgammaRIIb would be counter-productive in germinal center cells undergoing selection by affinity maturation, since these cells are thought to receive a survival/proliferative signal by interacting with antigen displayed on follicular dendritic cells. We have identified and characterized a population of B lymphocytes with low/negative FcgammaRIIb expression that are present in human tonsil. Phenotypically these cells correspond to germinal center B cells and comprise both centroblast and centrocyte populations. In examining expression at the molecular level we determined that these B cells do not express detectable mRNA for FcgammaRIIb. We examined several culture conditions to induce expression of FcgammaRIIb on germinal center cells but could not determine conditions that altered expression. We then examined the functional consequence of cross-linking membrane immunoglobulin and the receptor for IgG on human B lymphocytes. Our results cast some doubt on the value of anti-IgG as a model for antigen-antibody complexes in studying human B cell regulation.
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Affiliation(s)
- Peter J Macardle
- Department of Immunology, Allergy and Arthritis, Flinders Medical Centre and Flinders University of South Australia, Bedford Park, South Australia, Australia.
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Jessup CF, Ridings J, Ho A, Nobbs S, Roberton DM, Macardle P, Zola H. The Fc receptor for IgG (Fc gamma RII; CD32) on human neonatal B lymphocytes. Hum Immunol 2001; 62:679-85. [PMID: 11423173 DOI: 10.1016/s0198-8859(01)00257-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
B cells express an Fc receptor for IgG (FcgammaRII; CD32) which is involved in feedback inhibition of antibody production. Engagement of FcgammaRII during ligation of the antigen receptor provides an inhibitory signal. FcgammaRII exists as several isoforms, with FcgammaRIIb (which carries an immunoreceptor tyrosine-based inhibition motif; ITIM) being predominant form on adult B cells. The inhibitory role of FcgammaRIIb may be unhelpful to the infant, since primary exposure to infectious agents is likely to be in the presence of maternal IgG. We hypothesized that neonatal B cells would be less susceptible to feedback inhibition by antibody, either through the expression of activation-competent FcgammaRII isoforms (FcgammaRIIa and FcgammaRIIc) or through reduced expression of the inhibitory FcgammaRIIb isoforms. Cord and adult B cells were examined for expression of FcgammaRII isoforms using monoclonal antibodies and RT-PCR. In vitro assays were performed to assess susceptibility of cord and adult cells to FcgammaRII-mediated suppression. Although there is no phenotypic difference in FcgammaRII expression (FcgammaRIIb predominating on both adult and cord B cells), FcgammaRIIb is expressed at lower levels on cord cells. This quantitative difference in FcgammaRIIb expression may explain the reduced susceptibility of cord B cells to antibody-mediated inhibition observed in these experiments.
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Affiliation(s)
- C F Jessup
- Child Health Research Institute, Womens and Childrens Hospital, 5006, North Adelaide SA, Australia
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13
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Gagro A, McCloskey N, Challa A, Holder M, Grafton G, Pound JD, Gordon J. CD5-positive and CD5-negative human B cells converge to an indistinguishable population on signalling through B-cell receptors and CD40. Immunology 2000; 101:201-9. [PMID: 11012773 PMCID: PMC2327066 DOI: 10.1046/j.1365-2567.2000.00098.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Whether CD5 on B cells marks a subset functionally distinct from the conventional CD5 negative (CD5neg) adult population or is more an indicator of activation, remains contentious. Here we have investigated whether CD5 positive (CD5pos) and CD5neg B cells can be distinguished in terms of their response to surrogate signals aimed to model, in vitro, T-cell dependent (TD) and T-independent (TI) encounters with antigen in vivo: the predominantly CD5pos B-cell population found in cord blood, CD5 B cells positively selected from tonsils and their CD5neg counterparts, were compared. Neonatal B cells displayed a near-identical phenotype to that of adult CD5pos B cells, being characterized by uniform immunoglobulin M (IgM), immunoglobulin D (IgD), CD23 and CD44 coexpression. When cultured with anti-IgM maintained at high density on CD32-tranfected mouse L cells to model TI responses or on CD40 ligand (CD40L)-bearing L cells (with or without captured anti-IgM) to model TD encounters, DNA synthesis was stimulated to a similar extent in all three populations. Focusing on CD5 and CD23, we found that - although the signals delivered promoted distinct profiles of expression - under each condition of activation, the phenotypes that emerged for adult CD5pos and CD5neg B cells were remarkably similar. Neonatal B cells displayed a greater diminution in CD5 expression than adult CD5pos B cells following CD40 signals but otherwise the two populations again behaved similarly. The inclusion of interleukin-4 (IL-4) to cultures where cells were costimulated via surface (s)IgM and CD40 resulted in a complete loss of CD5 expression and a corresponding hyperexpression of CD23, irrespective of the population studied. The near-identical response of CD5pos and CD5neg B cells to surrogate TD or TI signals in vitro and their convergence to indistinguishable phenotypes is wholly supportive of CD5 being a fluctuating marker of activation rather than it delineating functionally distinct subsets.
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Affiliation(s)
- A Gagro
- The Medical Research Council Centre for Immune Regulation, University of Birmingham, The Medical School, Birmingham, UK
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14
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Affiliation(s)
- P G Holt
- TVW Telethon Institute for Child Health Research, Perth, Australia
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15
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Marshall-Clarke S, Reen D, Tasker L, Hassan J. Neonatal immunity: how well has it grown up? IMMUNOLOGY TODAY 2000; 21:35-41. [PMID: 10637557 DOI: 10.1016/s0167-5699(99)01548-0] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- S Marshall-Clarke
- Dept of Human Anatomy and Cell Biology, The University of Liverpool, Liverpool, UK L69 3GE.
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Abstract
We have characterized the T lymphocyte population of the human neonate in respect of the expression of phenotypic profiles for naive, memory and differentiated populations. We have examined the response of the neonate T cell to the superantigen Staphylococcus enterotoxin B (SEB) and compared the response to T cells from healthy adults. We found that the primary response to SEB is equivalent in neonates and adults but that the secondary response demonstrates hyporesponsiveness in the neonate that is more profound than in adults. This response was associated with increased expression of CD25; the alpha chain of the IL-2 receptor, equivalent to that seen in responding cells from adults. A modest increased expression of CD122 and CD132, the beta and gamma chains of the IL-2 receptor, was also observed. There was no increase in the IL-4 receptor (CD124). The hyporesponsive neonate T cells proliferated in response to exogenous IL-2 but the response was less than none SEB treated cells. The neonate cells did not respond to IL-4. We also examined the expression of MHC class II molecules on SEB stimulated cells and found that both neonate and adult T cells upregulate MHC class II to a similar degree. The difference in the hyporesponsive cells appears to result in part from a lower production of IL-2 and in part from a lower ability of cord cells to respond to IL-2. Since the stimulated cord cells expressed IL-2 receptor at the same levels as similarly treated adult cells; there may be differences in down stream signaling pathways.
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Affiliation(s)
- P J Macardle
- Department of Immunology, Allergy and Arthritis, Flinders Medical Centre, Bedford Park, South Australia.
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Abstract
The human infant is a major subject of immunization to prevent infectious disease. A better understanding of immune responses in human infants could lead to more effective immunization. Analysis of individual mechanisms is a prerequisite to understanding the whole response. We have examined the mutation and selection of immunoglobulin genes, mechanisms required for the maturation of antibody affinity. Mutations were rare in cord blood and were not detected in peripheral blood of infants under 10 days of age. Mutations were detected in most blood samples from infants aged 10 days to 2 months but the number of mutations was generally low compared with adults and there was limited evidence of selection. The ability to make and select mutated Ig increased over the 2-8 months period, but did not reach adult levels. Neonates differ from adults in the expression of several components of the immune system that may take part in affinity maturation, including cytokine receptors, antigen receptor and co-stimulator molecules. Thus, the mechanisms required to make high-affinity antibody develop gradually during the first year of life. Possible evolutionary reasons for this are discussed.
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Affiliation(s)
- H Zola
- Child Health Research Institute, Adelaide, South Australia.
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