Long primed germinal centers with enduring affinity maturation and clonal migration
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA862907 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR20673700_1.fastq.gz | Fastqsanger.gz | |||
| SRR20673700_2.fastq.gz | Fastqsanger.gz | |||
| SRR20673701_1.fastq.gz | Fastqsanger.gz | |||
| SRR20673701_2.fastq.gz | Fastqsanger.gz | |||
| SRR20673702_1.fastq.gz | Fastqsanger.gz |
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Project description:Germinal centers (GCs) are the engines of antibody evolution. Using HIV Env protein immunogen priming in rhesus monkeys (RM) followed by a long period without further immunization, we demonstrate GC B cells (BGC) lasted at least 6 months. A 186-fold BGC cell increase was present by week 10 compared to a conventional immunization. Single cell transcriptional profiling revealed both light and dark zone GC states were sustained. Antibody somatic hypermutation (SHM) 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, suggesting they could be active for even longer periods of time. High HIV neutralizing antibody titers were generated after a single booster immunization. Fully glycosylated HIV trimer protein is a complex antigen, posing significant immunodominance challenges for B cells. Memory B cells (BMem) generated under these long priming conditions had higher levels of SHM, and both BMem cells and antibodies were more likely to recognize non-immunodominant epitopes. Numerous BGC cell lineage phylogenies spanning the >6-month GC period were identified, demonstrating continuous GC activity and selection for at least 191 days with no additional antigen exposure. A long prime, slow delivery (12-day) immunization approach holds promise for difficult vaccine targets, and suggests that patience can have great value for tuning GCs to maximize antibody responses.
2022-09-15 | GSE209904 | GEO
Project description:Clonal replacement sustains long-lived germinal centers primed by respiratory viruses
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Project description:Germinal centers (GCs) form in secondary lymphoid organs in response to infection and immunization and are the source of affinity-matured B cells. The duration of GC reactions spans a wide range, and long-lasting GCs (LLGCs) are potentially a source of highly mutated B cells. We show that, rather than consisting of continuously evolving B cell clones, LLGCs elicited by influenza virus or SARS-CoV-2 infection in mice are sustained by progressive replacement of founder clones by naïve-derived invader B cells that do not detectably bind viral antigens. Rare founder clones that resist replacement for long periods are enriched in clones with heavily mutated immunoglobulins, including some with very high affinity for antigen, that can be recalled by boosting. Our findings reveal underappreciated aspects of the biology of LLGCs generated by respiratory virus infection and identify clonal replacement as a potential constraint on the development of highly mutated antibodies within these structures.
2022-12-31 | GSE218165 | GEO
Project description:Protective immune responses to many pathogens depend on the development of high affinity antibody-producing plasma cells in germinal centers. Transgenic models suggest that there is a stringent affinity-based barrier to plasma cell development. Whether a similar high affinity barrier regulates plasma cell development under physiologic circumstances, and the nature of the plasma cell fate decision has not been defined precisely. Here we use a fate mapping approach to examine the relationship between germinal center (GC) B cells selected to undergo additional rounds of affinity maturation, germinal center pre-plasma cells and plasma cells. The data show that initial plasma cell selection overlaps with germinal center B cell selection, but that the plasma cell compartment accumulates a less diverse and higher affinity collection of antibodies over time. Thus, whereas the GC continues to diversify over time, affinity-based pre-plasma cell selection sieves the germinal center to enable accumulation of a more restricted group of high affinity antibody secreting plasma cells.
2023-11-02 | GSE246382 | GEO
Project description: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.
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Project description:Antibody affinity maturation occurs in secondary lymphoid organs within germinal centers (GCs) where B cells mutate their antibody-encoding genes in the dark zone (DZ) followed by a selection of the high-affinity variants in the light zone (LZ) by T cells. The amount of the T cell-derived selection signals is proportional to the BCR affinity and the magnitude of Myc expression. However, since the lifetimes of Myc mRNA and protein are extremely short, it is unclear how high levels of Myc are maintained in the GC B cell to allow positive selection. Here, by measuring Myc transcripts in situ at the single-cell level, we find that T cell help promotes the frequency of Myc transcriptional bursts. T cell help primarily increases the number of Myc-positive cells rather than the amount of Myc per cell. Measurement of Myc intronic and exonic transcripts in situ demonstrates that positive selection is mediated by Myc transcriptional bursts through a rapid increase in the active transcription sites rather than an elevation in transcription rate or gene accessibility. Thus, the amount of Myc transcriptional bursts over time in the LZ, rather than Myc abundance, dictates B cell selection in germinal centers.
2024-10-15 | GSE237128 | GEO
Project description:Antibody responses are characterized by increasing affinity and diversity over time. Affinity maturation occurs in germinal centers by a mechanism that involves repeated cycles of somatic mutation and selection. How antibody responses diversify while also undergoing affinity maturation is not as well understood. Here, we examined germinal center (GC) dynamics by tracking B cell entry, division, somatic mutation and specificity. Our experiments show that naïve B cells continuously enter GCs where they compete for T cell help and undergo clonal expansion. Consistent with late entry, invaders carry fewer mutations but can contribute up to 30 % or more of the cells in late-stage germinal centers. Notably, cells entering the germinal center at later stages of the reaction diversify the immune response by expressing receptors that show low affinity to the immunogen. Paradoxically, the affinity threshold for late GC entry is lowered in the presence of high affinity antibodies.
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Project description:Peyer’s Patch Germinal Centers Select Innate-like BCRs
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Project description:Ig diversification occurs in peripheral lymphoid organs after establishment of central tolerance during B cell development. In germinal centers (GCs), somatic hypermutation of Ig genes occurs in dark zones, followed by selection of mutated clones in light zones (LZs). This generates high-affinity Ig receptors to pathogens but can also produce autoreactive Ig receptors, which are removed by selection mechanisms that are incompletely understood. The ubiquitin ligase Itch prevents the emergence of autoimmune disease and autoantibodies in humans and mice, and patients lacking Itch develop potentially fatal autoimmune diseases; yet, how Itch regulates GC B cells is not well understood. By studying Itch-deficient mice, we have recently shown that Itch directly limits the magnitude of GC responses. Proteomic profiling of GC B cells uncovered that Itch-deficient cells exhibit high mTORC1 and Myc activity, hallmarks of positive selection. Bone marrow chimera and adoptive transfer experiments revealed that B cell Itch restricts noncycling LZ cells. These results support, t our knowledge, a novel role for Itch in skewing selection of GC B cells to restrict LZ accumulation and shape GC-derived humoral immunity. Determining how B cells integrate cues within GCs to navigate through LZs and dark zones will aid in understanding how autoreactive clones emerge from GCs in people with autoimmune disease.
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