Work

Metabolic and functional changes in T helper cells during the periparturient period of dairy cows

Year: 2025

Type: article

Abstract: ) cells across the periparturient period remains poorly understood. This study evaluated the in vitro metabolic function, proliferation capacity and phenotype of T helper cells across the periparturient period. Multiparous Holstein cows (n = 22) having mean ± SD lactation of 4.16 ± 1.34 were sampled at -28, +3, and +28 d relative to calving. Peripheral blood mononuclear cells were isolated and T helper cells were obtained using magnetic sorting. A Seahorse XF HS Mini analyzer was used to assess the metabolic function through a T cell metabolic persistence assay, measuring glycolysis and oxidative phosphorylation via extracellular acidification and oxygen consumption rates respectively. Cells were treated either with assay medium (nonactivated) or phorbol 12-myristate 13-acetate and ionomycin (activated) for metabolic measurements, as this combination induces rapid, receptor-independent activation. For proliferation capacity, isolated T helper cells were incubated with concanavalin A, as it provides sustained stimulation to assess clonal expansion, for 72h and tracked using cell trace in a flow cytometer. Cytokine production was measured in the cell culture supernatant using a MILLIPLEX Bovine Cytokine/Chemokine kit. RNA was extracted from isolated cells, and gene expression of immune-related and metabolic markers were evaluated by quantitative PCR. Data were analyzed using a linear mixed effect model in R 4.4.3 using day relative to calving, activation status and block as fixed effect and cow as a random effect. When properly, time of the assay and its interaction with day relative to calving was included as a fixed effect. Activated T helper cells showed greater glycolytic and oxidative metabolism at +3 and +28 d compared with -28. Expansion index was highest at +3 (2.65), followed by +28 (2.38) and -28 (1.91). Proinflammatory cytokine production, like IL-1 α, IL-1 β and IL-6 also increased during +3 and +28 compared with -28. However, no significant differences in gene expression were detected across time points. These findings suggest that T helper cell metabolism and proliferation capacity are upregulated after calving and that these cells express a more proinflammatory phenotype, indicating that after parturition, immune function on this subset of cells does not appear to be suppressed.

Source: Journal of Dairy Science

DOI: 10.3168/jds.2025-27307