ABSTRACT:The transition period is the most critical time of the cow's lactation cycle that is associated with the onset of mastitis. In this study, changes of plasma proteins in cows (n = 12) with or without subclinical mastitis after calving were determined by two-dimensional electrophoresis (2-DE), which detected 18 spots with variations in protein spots abundance. These spots were identified by liquid chromatography coupled with tandem mass spectrometry. The changes in protein profile from day 21 before calving to day 1 after calving were similar in cows with or without subclinical mastitis. Abundance of α1 acid glycoprotein (AGP) and haptoglobin was dramatically increased at parturition, while transthyretin was down-regulated at parturition, and apolipoprotein E and immunoglobulin gamma 1 were up-regulated at postpartum compared with prepartum in periparturient dairy cows. In cows infected with subclinical mastitis, AGP, haptoglobin, and serum amyloid A were dramatically increased and continued to be elevated in plasma from day 1 to day 21 after calving compared with cows free of mastitis. Changes of protein in plasma at parturition may serve as an immune system response to parturition and lactation process at the protein level and suggest that these altered proteins would not serve as a potential marker for predicting if the periparturient dairy cows are susceptible to subclinical mastitis.

This study is an exploratory analysis for understanding the effect of a duodenal infusion of an a-linolenic acid (LNA) on the plasma and milk proteome of lactating dairy cows. Four primiparous Holstein cows were fitted with duodenal cannulas and received 0, 100, 200, 300 and 400 g/day of LNA in a two-treatment crossover design. Blood and milk were collected for determination of protein composition by two-dimensional gel electrophoresis. Alteration of protein spots was detected and identified using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS). Plasma haptoglobin levels, and milk b-casein A2, a s1 -casein variant and albumin, did not differ in cows after infusion of 0, 100, 200 and 300 g/day of LNA, but were increased after the cows received duodenal infusion of 400 g/day of LNA. Western blot analysis of haptoglobin expression in plasma confirmed the alterations in protein expression seen using MS. This study demonstrated that infusion of high doses of LNA by duodenal cannula can result in metabolic stress within the bovine intestine and in changes in milk composition.

Co-expression of chimeric switch receptors (CSRs) specific for PD-L1 improves the antitumor effects of chimeric antigen receptor (CAR) T cells. However, the effects of trans-recognition between CSRs and PD-L1 expressed by activated CAR T cells remain unclear. Here, we design a CSR specific for PD-L1 (CARP), containing the transmembrane and cytoplasmic signaling domains of CD28 but not the CD3 ζ chain. We show that CARP T cells enhance the antitumor activity of anti-mesothelin CAR (CARMz) T cells in vitro and in vivo. In addition, confocal microscopy indicates that PD-L1 molecules on CARMz T cells accumulate at cell-cell contacts with CARP T cells. Using single-cell RNA-sequencing analysis, we reveal that CARP T cells promote CARMz T cells differentiation into central memory-like T cells, upregulate genes related to Th1 cells, and downregulate Th2-associated cytokines through the CD70-CD27 axis. Moreover, these effects are not restricted to PD-L1, as CAR19 T cells expressing anti-CD19 CSR exhibit similar effects on anti-PSCA CAR T cells with truncated CD19 expression. These findings suggest that target trans-recognition by CSRs on CAR T cells may improve the efficacy and persistence of CAR T cells via the CD70-CD27 axis.

The proteome of rumen epithelial tissue was analysed by SDS-PAGE coupled with LC-MS/MS. 813 non-redundant proteins were identified of which 7.4 % featured membrane-spanning domains and 15.4 % harboured a signal peptide. According to the gene ontology annotation, the most abundant proteins exhibited binding activities related to their molecular functions, were proteins of cellular components or belonged to various metabolic processes. A predominant group of canonical pathways in the rumen epithelial tissue was identified using the IPA software. The GeLC-MS/MS approach was used to characterise the entire protein expression repertoire in rumen tissue, providing a more detailed understanding of the important biological processes in the rumen.

This study provides relevent information that contributes to the understanding of parameters affecting variability of milk fatty acid profiles.