Figure 5.

PLA2G1B is involved in PDAC plasma inhibition of the CD4 T-cell pSTAT5-NT response. (A) A 3S-like peptide from P. gingivalis (OmpA Pg) increases PLA2G1B enzymatic activity. [3H]-AA-labeled Jurkat T cells were pretreated with 3S, OmpA Pg or scrambled 3S (Scr 3S) peptides (11µM) for 21 h and incubated alone or with PLA2G1B (200 nM). Results are shown as the mean ± SD of PLA2G1B activity with the 3S or OmpA Pg minus PLA2G1B activity with Scr 3S from one representative experiment of two with similar results. (B) ELISA quantification of active PLA2G1B and proPLA2G1B in plasma from HD and PDAC donors (the median is shown). (C) Anti-PLA2G1B mAb inhibits PLA2G1B activity in PDAC plasma. HD CD4 T cells from three donors were treated with PLA2G1B (75 nM), 3% of PDAC plasma (PDACp) alone (w/o Ab, n = 9 plasma samples), with control isotype (ctrl iso, 667 nM, n = 6 plasma samples) or anti-PLA2G1B mAb (14G9, 667 nM, n = 8 plasma samples) and the pSTAT5-NT cell response to IL-7 was analyzed by confocal microscopy. Results are shown as the mean ± SD of percentage of pSTAT5-NT cells inhibition. (D) Heterogeneity of anti-PLA2G1B mAb 14G9 inhibition of PLA2G1B activity in PDAC plasma. Results are shown as the mean ± SD of the percentage of inhibition of PDACp activity from six patients on pSTAT5-NT by 14G9 relative to that of control isotype-treated plasma. *p < 0.05, and **p < 0.01, by two-way ANOVA with Tukey’s correction for multiple comparisons for A, by the Mann-Whitney test for B and D, and by the Kruskal-Wallis test followed by the Mann-Whitney test, with p-values adjusted for multiple comparisons between groups, for C. ns, non significant.