Exercise-induced B cell mobilisation: Preliminary evidence for an influx of immature cells into the bloodstream

Abstract

The number of peripheral blood B lymphocytes doubles during acute exercise, but the phenotypic composition of this response remains unknown. In two independent exercise studies, using complimentary phenotyping strategies, we investigated the mobilisation patterns of distinct B cell subsets. In study one, nine healthy males (mean±SD age: 22.1±3.4years) completed a continuous cycling bout at 80% V̇O2MAX for 20min. In study two, seven healthy experienced cyclists (mean±SD age: 29.9±4.7years) completed a 30min cycling trial at a workload corresponding to +5% of the individual blood lactate threshold. In study one, CD3-CD19+ B cell subsets were classified into immature (CD27-CD10+), naïve (CD27-CD10-), memory (CD27+CD38-), plasma cells/plasmablasts (CD27+CD38+) and finally, recently purported 'B1' cells (CD27+ CD43+ CD69-). In study two, CD20+ B cells were classified into immature (CD27-IgD-), naïve (CD27-IgD+), and IgM+/IgG+/IgA+ memory cells (CD27+IgD-). Total B cells exhibited a mean increase of 88% (study one) and 60% (study two) during exercise. In both studies, immature cells displayed the greatest increase, followed by memory cells, then naïve cells (study one: immature 130%>mature 105%>naïve 84%; study two: immature 110%>mature 56%>naïve 38%). Our findings show that, unlike T cells and NK cells, B cell mobilisation is not driven by effector status, and, for the first time, that B cell mobilisation during exercise is comprised of immature CD27- IgD-/CD10+ cells.

Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan

“…This exercise intensity-dependent mobilization is driven in part by increased shear forces and blood pressure during exercise causing a non-specific flushing of the marginal pools ( 82 ) but, moreover, is principally governed by adrenergic stimulation of beta-2-adrenergic receptors on the surface of lymphocytes, arising from adrenaline released during exercise, causing endothelial detachment and subsequent recirculation of lymphocytes into the bloodstream ( 83 – 85 ). Indeed, the lymphocyte mobilization response observed during exercise appears to broadly mirror the differential expression of beta-2 adrenergic receptors on lymphocytes: natural killer cells > CD8 + T cells > B cells > CD4 + T cells, including regulatory T cells ( 81 , 86 – 88 ). Upon exercise cessation, the classic biphasic exercise response is next characterized by a dramatic decrease in the frequency of lymphocytes in the bloodstream.…”

Impact of exercise on the immune system and outcomes in hematologic malignancies

“…These cells follow a typical acute exercise pattern in which numbers increase before decreasing below basal levels during recovery from exercise. 42,98 Specifically, acute exercise in young adults mobilizes immature (CD27 neg /IgD neg /CD10 pos ) B cells to the greatest extent. Total B-cell numbers increased after exercise, including memory (CD27 pos /CD38 neg ) and naive (CD27 neg /CD10 neg ) cells.…”

Plasma cells: You are what you eat

“…Yet limited data suggest that exercise has minimal effects on B cells and plasma cell function in both mice and humans. [237][238][239] As above, measuring the impact of obesity and exercise on plasma cell-intrinsic metabolism will be critical for moving the field from observations of phenomena to mechanistic studies.…”