Pivotal Advance: Peritoneal cavity B-1 B cells have phagocytic and microbicidal capacities and present phagocytosed antigen to CD4+ T cells
Bibliographic record
Abstract
Breaking the long-held paradigm that primary B cells are not phagocytic, several studies have demonstrated recently that B cells from fish, amphibians, and reptilians have a significant phagocytic capacity. Whether such capacity has remained conserved in certain mammalian B cell subsets is presently an enigma. Here, we report a previously unrecognized ability of PerC B-1a and B-1b lymphocytes to phagocytose latex beads and bacteria. In contrast, B-2 lymphocytes had an almost negligible ability to internalize these particles. Upon phagocytosis, B-1a and B-1b cells were able to mature their phagosomes into phagolysosomes and displayed the ability to kill internalized bacteria. Importantly, B-1a and B-1b cells effectively present antigen recovered from phagocytosed particles to CD4(+) T cells. However, these cells showed a much lower competence to present soluble antigen or antigen from large, noninternalized particles. B-1 B cells presented particulate and soluble antigen to CD4(+) T cells more efficiently than macrophages, whereas DCs were the most potent APCs. The novel phagocytic and microbicidal abilities identified in B-1 B lymphocytes strengthen the innate nature that has long been attributed to these cells. In the context of adaptive immunity, we show that these innate immune processes are relevant, as they enable B-1 B cells to present phagocytosable particulate antigen. These capacities position these cells at the crossroads that link innate with adaptive immune processes. In a broader context, these newly identified capacities of B-1 B cells further support the previously recognized functional, developmental, and evolutionary relationships between these cells and macrophages.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.006 | 0.003 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.006 | 0.004 |
| Insufficient payload (model declined to judge) | 0.065 | 0.026 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".