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1.
Immunity ; 57(2): 245-255.e5, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38228150

RESUMO

Long-lived plasma cells (PCs) secrete antibodies that can provide sustained immunity against infection. High-affinity cells are proposed to preferentially select into this compartment, potentiating the immune response. We used single-cell RNA-seq to track the germinal center (GC) development of Ighg2A10 B cells, specific for the Plasmodium falciparum circumsporozoite protein (PfCSP). Following immunization with Plasmodium sporozoites, we identified 3 populations of cells in the GC light zone (LZ). One LZ population expressed a gene signature associated with the initiation of PC differentiation and readily formed PCs in vitro. The estimated affinity of these pre-PC B cells was indistinguishable from that of LZ cells that remained in the GC. This remained true when high- or low-avidity recombinant PfCSP proteins were used as immunogens. These findings suggest that the initiation of PC development occurs via an affinity-independent process.


Assuntos
Linfócitos B , Centro Germinativo , Plasmócitos , Diferenciação Celular , Células Precursoras de Linfócitos B
2.
Nature ; 632(8025): 630-636, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39085605

RESUMO

The upper airway is an important site of infection, but immune memory in the human upper airway is poorly understood, with implications for COVID-19 and many other human diseases1-4. Here we demonstrate that nasal and nasopharyngeal swabs can be used to obtain insights into these challenging problems, and define distinct immune cell populations, including antigen-specific memory B cells and T cells, in two adjacent anatomical sites in the upper airway. Upper airway immune cell populations seemed stable over time in healthy adults undergoing monthly swabs for more than 1 year, and prominent tissue resident memory T (TRM) cell and B (BRM) cell populations were defined. Unexpectedly, germinal centre cells were identified consistently in many nasopharyngeal swabs. In subjects with SARS-CoV-2 breakthrough infections, local virus-specific BRM cells, plasma cells and germinal centre B cells were identified, with evidence of local priming and an enrichment of IgA+ memory B cells in upper airway compartments compared with blood. Local plasma cell populations were identified with transcriptional profiles of longevity. Local virus-specific memory CD4+ TRM cells and CD8+ TRM cells were identified, with diverse additional virus-specific T cells. Age-dependent upper airway immunological shifts were observed. These findings provide new understanding of immune memory at a principal mucosal barrier tissue in humans.


Assuntos
Memória Imunológica , Células B de Memória , Células T de Memória , Mucosa Nasal , Nasofaringe , SARS-CoV-2 , Adulto , Humanos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , COVID-19/imunologia , COVID-19/virologia , Centro Germinativo/imunologia , Centro Germinativo/citologia , Imunoglobulina A/imunologia , Memória Imunológica/imunologia , Células B de Memória/imunologia , Células T de Memória/imunologia , Mucosa Nasal/imunologia , Mucosa Nasal/virologia , Nasofaringe/virologia , Nasofaringe/imunologia , Plasmócitos/imunologia , Plasmócitos/citologia , SARS-CoV-2/imunologia
3.
Nature ; 609(7929): 998-1004, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36131022

RESUMO

Germinal centres are the engines of antibody evolution. Here, using human immunodeficiency virus (HIV) Env protein immunogen priming in rhesus monkeys followed by a long period without further immunization, we demonstrate germinal centre B (BGC) cells that last for at least 6 months. A 186-fold increase in BGC cells was present by week 10 compared with conventional immunization. Single-cell transcriptional profiling showed that both light- and dark-zone germinal centre states were sustained. Antibody somatic hypermutation of BGC cells continued to accumulate throughout the 29-week priming period, with evidence of selective pressure. Env-binding BGC cells were still 49-fold above baseline at 29 weeks, which suggests that they could remain active for even longer periods of time. High titres of HIV-neutralizing antibodies were generated after a single booster immunization. Fully glycosylated HIV trimer protein is a complex antigen, posing considerable immunodominance challenges for B cells1,2. Memory B cells generated under these long priming conditions had higher levels of antibody somatic hypermutation, and both memory B cells and antibodies were more likely to recognize non-immunodominant epitopes. Numerous BGC cell lineage phylogenies spanning more than the 6-month germinal centre period were identified, demonstrating continuous germinal centre activity and selection for at least 191 days with no further antigen exposure. A long-prime, slow-delivery (12 days) immunization approach holds promise for difficult vaccine targets and suggests that patience can have great value for tuning of germinal centres to maximize antibody responses.


Assuntos
Afinidade de Anticorpos , Linfócitos B , Movimento Celular , Células Clonais , Centro Germinativo , Anticorpos Anti-HIV , Imunização , Animais , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/imunologia , Afinidade de Anticorpos/genética , Afinidade de Anticorpos/imunologia , Linfócitos B/citologia , Linfócitos B/imunologia , Células Clonais/citologia , Células Clonais/imunologia , Epitopos de Linfócito B/imunologia , Perfilação da Expressão Gênica , Centro Germinativo/citologia , Centro Germinativo/imunologia , Anticorpos Anti-HIV/genética , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Humanos , Imunização Secundária , Macaca mulatta/imunologia , Macaca mulatta/virologia , Células B de Memória/citologia , Células B de Memória/imunologia , Análise de Célula Única , Hipermutação Somática de Imunoglobulina/genética , Hipermutação Somática de Imunoglobulina/imunologia , Fatores de Tempo , Produtos do Gene env do Vírus da Imunodeficiência Humana/administração & dosagem , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia
5.
J Immunol ; 206(7): 1505-1514, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33658297

RESUMO

IKZF1 (IKAROS) is essential for normal lymphopoiesis in both humans and mice. Previous Ikzf1 mouse models have demonstrated the dual role for IKZF1 in both B and T cell development and have indicated differential requirements of each zinc finger. Furthermore, mutations in IKZF1 are known to cause common variable immunodeficiency in patients characterized by a loss of B cells and reduced Ab production. Through N-ethyl-N-nitrosourea mutagenesis, we have discovered a novel Ikzf1 mutant mouse with a missense mutation (L132P) in zinc finger 1 (ZF1) located in the DNA binding domain. Unlike other previously reported murine Ikzf1 mutations, this L132P point mutation (Ikzf1L132P ) conserves overall protein expression and has a B cell-specific phenotype with no effect on T cell development, indicating that ZF1 is not required for T cells. Mice have reduced Ab responses to immunization and show a progressive loss of serum Igs compared with wild-type littermates. IKZF1L132P overexpressed in NIH3T3 or HEK293T cells failed to localize to pericentromeric heterochromatin and bind target DNA sequences. Coexpression of wild-type and mutant IKZF1, however, allows for localization to pericentromeric heterochromatin and binding to DNA indicating a haploinsufficient mechanism of action for IKZF1L132P Furthermore, Ikzf1+/L132P mice have late onset defective Ig production, similar to what is observed in common variable immunodeficiency patients. RNA sequencing revealed a total loss of Hsf1 expression in follicular B cells, suggesting a possible functional link for the humoral immune response defects observed in Ikzf1L132P/L132P mice.


Assuntos
Linfócitos B/imunologia , Imunodeficiência de Variável Comum/genética , Fator de Transcrição Ikaros/genética , Mutação Puntual/genética , Animais , Formação de Anticorpos , Células HEK293 , Haploinsuficiência , Fatores de Transcrição de Choque Térmico/genética , Fatores de Transcrição de Choque Térmico/metabolismo , Humanos , Fator de Transcrição Ikaros/metabolismo , Imunoglobulinas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Células NIH 3T3
6.
Eur J Immunol ; 50(8): 1187-1194, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32222961

RESUMO

Atypical memory B cells (aMBCs) are found in elevated numbers in individuals exposed to malaria. A key question is whether malaria induces aMBCs as a result of exposure to Ag, or non-Ag-specific mechanisms. We identified Plasmodium and bystander tetanus toxoid (TT) specific B cells in individuals from areas of previous and persistent exposure to malaria using tetramers. Malaria-specific B cells were more likely to be aMBCs than TT-specific B cells. However, TT-specific B cells from individuals with continuous exposure to malaria were more likely to be aMBCs than TT-specific B cells in individuals from areas where transmission has ceased. Finally, sequences of BCRs specific for a blood stage malaria-Ag were more highly mutated than sequences from TT-specific BCRs and under strong negative selection, indicative of ongoing antigenic pressure. Our data suggest both persistent Ag exposure and the inflammatory environment shape the B-cell response to malaria and bystander Ags.


Assuntos
Antígenos de Protozoários/imunologia , Linfócitos B/imunologia , Efeito Espectador/imunologia , Malária/imunologia , Plasmodium falciparum/imunologia , Humanos , Memória Imunológica , Fenótipo , Toxoide Tetânico/imunologia
7.
PLoS Pathog ; 13(7): e1006469, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28759640

RESUMO

The repeat region of the Plasmodium falciparum circumsporozoite protein (CSP) is a major vaccine antigen because it can be targeted by parasite neutralizing antibodies; however, little is known about this interaction. We used isothermal titration calorimetry, X-ray crystallography and mutagenesis-validated modeling to analyze the binding of a murine neutralizing antibody to Plasmodium falciparum CSP. Strikingly, we found that the repeat region of CSP is bound by multiple antibodies. This repeating pattern allows multiple weak interactions of single FAB domains to accumulate and yield a complex with a dissociation constant in the low nM range. Because the CSP protein can potentially cross-link multiple B cell receptors (BCRs) we hypothesized that the B cell response might be T cell independent. However, while there was a modest response in mice deficient in T cell help, the bulk of the response was T cell dependent. By sequencing the BCRs of CSP-repeat specific B cells in inbred mice we found that these cells underwent somatic hypermutation and affinity maturation indicative of a T-dependent response. Last, we found that the BCR repertoire of responding B cells was limited suggesting that the structural simplicity of the repeat may limit the breadth of the immune response.


Assuntos
Anticorpos Antiprotozoários/imunologia , Linfócitos B/imunologia , Vacinas Antimaláricas/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Linfócitos T/imunologia , Animais , Afinidade de Anticorpos , Cristalografia por Raios X , Feminino , Humanos , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Plasmodium falciparum/química , Plasmodium falciparum/genética , Proteínas de Protozoários/administração & dosagem , Proteínas de Protozoários/química , Proteínas de Protozoários/genética
8.
Science ; 384(6697): eadj8321, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38753769

RESUMO

Germline-targeting immunogens hold promise for initiating the induction of broadly neutralizing antibodies (bnAbs) to HIV and other pathogens. However, antibody-antigen recognition is typically dominated by heavy chain complementarity determining region 3 (HCDR3) interactions, and vaccine priming of HCDR3-dominant bnAbs by germline-targeting immunogens has not been demonstrated in humans or outbred animals. In this work, immunization with N332-GT5, an HIV envelope trimer designed to target precursors of the HCDR3-dominant bnAb BG18, primed bnAb-precursor B cells in eight of eight rhesus macaques to substantial frequencies and with diverse lineages in germinal center and memory B cells. We confirmed bnAb-mimicking, HCDR3-dominant, trimer-binding interactions with cryo-electron microscopy. Our results demonstrate proof of principle for HCDR3-dominant bnAb-precursor priming in outbred animals and suggest that N332-GT5 holds promise for the induction of similar responses in humans.


Assuntos
Vacinas contra a AIDS , Anticorpos Amplamente Neutralizantes , Regiões Determinantes de Complementaridade , Centro Germinativo , Anticorpos Anti-HIV , Animais , Humanos , Vacinas contra a AIDS/imunologia , Linfócitos B/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Regiões Determinantes de Complementaridade/imunologia , Microscopia Crioeletrônica , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Centro Germinativo/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , HIV-1/imunologia , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias Pesadas de Imunoglobulinas/genética , Macaca mulatta , Células B de Memória/imunologia
9.
Immunol Cell Biol ; 95(10): 862-863, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29066798

Assuntos
Anticorpos
10.
Cell Rep ; 35(2): 108996, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33852850

RESUMO

Antibodies targeting the NANP/NVDP repeat domain of the Plasmodium falciparum circumsporozoite protein (CSPRepeat) can protect against malaria. However, it has also been suggested that the CSPRepeat is a decoy that prevents the immune system from mounting responses against other domains of CSP. Here, we show that, following parasite immunization, B cell responses to the CSPRepeat are immunodominant over responses to other CSP domains despite the presence of similar numbers of naive B cells able to bind these regions. We find that this immunodominance is driven by avid binding of the CSPRepeat to cognate B cells that are able to expand at the expense of B cells with other specificities. We further show that mice immunized with repeat-truncated CSP molecules develop responses to subdominant epitopes and are protected against malaria. These data demonstrate that the CSPRepeat functions as a decoy, but truncated CSP molecules may be an approach for malaria vaccination.


Assuntos
Anticorpos Antiprotozoários/biossíntese , Imunização/métodos , Vacinas Antimaláricas/administração & dosagem , Malária/prevenção & controle , Peptídeos/administração & dosagem , Plasmodium berghei/efeitos dos fármacos , Proteínas de Protozoários/genética , Animais , Anopheles/parasitologia , Anticorpos Neutralizantes/biossíntese , Linfócitos B/imunologia , Linfócitos B/parasitologia , Feminino , Expressão Gênica , Malária/imunologia , Malária/parasitologia , Vacinas Antimaláricas/biossíntese , Vacinas Antimaláricas/genética , Camundongos , Camundongos Endogâmicos C57BL , Peptídeos/genética , Peptídeos/imunologia , Plasmodium berghei/imunologia , Plasmodium berghei/patogenicidade , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/imunologia , Plasmodium falciparum/patogenicidade , Ligação Proteica , Proteínas de Protozoários/imunologia , Esporozoítos/imunologia , Esporozoítos/efeitos da radiação , Transgenes , Vacinas Atenuadas
11.
Cell Rep ; 34(6): 108684, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33567273

RESUMO

The diversity of circulating human B cells is unknown. We use single-cell RNA sequencing (RNA-seq) to examine the diversity of both antigen-specific and total B cells in healthy subjects and malaria-exposed individuals. This reveals two B cell lineages: a classical lineage of activated and resting memory B cells and an alternative lineage, which includes previously described atypical B cells. Although atypical B cells have previously been associated with disease states, the alternative lineage is common in healthy controls, as well as malaria-exposed individuals. We further track Plasmodium-specific B cells after malaria vaccination in naive volunteers. We find that alternative lineage cells are primed after the initial immunization and respond to booster doses. However, alternative lineage cells develop an atypical phenotype with repeated boosts. The data highlight that atypical cells are part of a wider alternative lineage of B cells that are a normal component of healthy immune responses.


Assuntos
Anticorpos Antiprotozoários/imunologia , Linfócitos B/imunologia , Vacinas Antimaláricas/administração & dosagem , Malária/imunologia , Plasmodium/imunologia , Vacinação , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Malária/prevenção & controle , Vacinas Antimaláricas/imunologia , Masculino , RNA-Seq
12.
Cell Host Microbe ; 28(4): 572-585.e7, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-32697938

RESUMO

Generating sufficient antibody to block infection is a key challenge for vaccines against malaria. Here, we show that antibody titers to a key target, the repeat region of the Plasmodium falciparum circumsporozoite protein (PfCSP), plateaued after two immunizations in a clinical trial of the radiation-attenuated sporozoite vaccine. To understand the mechanisms limiting vaccine responsiveness, we developed immunoglobulin (Ig)-knockin mice with elevated numbers of PfCSP-binding B cells. We determined that recall responses were inhibited by antibody feedback, potentially via epitope masking of the immunodominant PfCSP repeat region. Importantly, the amount of antibody that prevents boosting is below the amount of antibody required for protection. Finally, while antibody feedback limited responses to the PfCSP repeat region in vaccinated volunteers, potentially protective subdominant responses to PfCSP C-terminal regions expanded with subsequent boosts. These data suggest that antibody feedback drives the diversification of immune responses and that vaccination for malaria will require targeting multiple antigens.


Assuntos
Anticorpos Antiprotozoários/imunologia , Linfócitos B/imunologia , Vacinas Antimaláricas/imunologia , Vacinação , Animais , Anticorpos Antiprotozoários/genética , Formação de Anticorpos/imunologia , Epitopos/imunologia , Retroalimentação , Humanos , Imunização , Imunoglobulina G , Imunoglobulina M , Malária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Plasmodium falciparum/imunologia , Esporozoítos/imunologia , Vacinas Atenuadas
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