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We have deliberately targeted collaboration between T cells and certain B cells by using a heteroconjugate (HETCONJ) antibody. This specific reagent was created by cross-linking the F(ab')2 portions of and-I-Ab and ant)-CD3 monoclonal antibodies. Spleen cells from B6 (I-Ab) but not bm 12 (I-A'bm12) mice proliferated in vitro in the presence of the HETCONJ. Similarly. T-cell dependent IgM secretion was induced in B cells from B6, yet only weakly in B cells from bm12 mice. Using B cells from Igh allotype double congenic (B6.C20 Igha/I-Ab and bm12, Ighb/I-Abm12) mice in co-culture experiments, we have used the HETCONJ to study linked versus bystander T--B interaction. B-cell activation, mediated by HETCONJ, was 10 times greater in unseparated than in resting splenic B cells. T--B interaction through T--B contact was more efficient than activation through bystander effects both for unseparated and resting splenic B cells. Large, already activated B cells, in contrast, did not show a preference for linked recognition. Our reagent has mimicked some of the events involved in T--B collaboration and may be useful in studying the molecular basis of cellular interactions. [ABSTRACT FROM AUTHOR]

The thundering evolution of lung transplantation management during the past ten years and primary graft dysfunction (PGD) new definition have led to new predictive factors of PGD. Therefore, we retrospectively analyzed a monocenter database using a machine-learning method, to determine the predictive factors of grade 3 PGD (PGD3), defined as a PaO2/FiO2 ratio < 200 or being under extracorporeal membrane oxygenation (ECMO) at postoperative day 3. We included all double lung transplantation from 2012 to 2019 and excluded multi-organ transplant, cardiopulmonary bypass, or repeated transplantation during the study period for the same patient. Recipient, donor and intraoperative data were added in a gradient boosting algorithm step-by-step according to standard transplantation stages. Dataset was split randomly as 80% training set and 20% testing set. Relationship between predictive factors and PGD3 was represented as ShHapley Additive exPlanation (SHAP) values. A total 478 patients were included in the analysis, 83 (17.3%) had PGD3. Highest performance analysis was achieved at the end-surgery stage (0.87, IC95 [0.867-0.873]) with 6 predictive factors: being under ECMO at some point in the intervention and whatever the reason for its implementation is a predictor; a recipient low total lung capacity is a predictor; ECMO is a predictor whatever the time of implantation; having a cystic fibrosis or a COPD/emphysema is protective while having a lung pulmonary fibrosis or another pathology is predictive. Gradient boosting predicted PGD3 with high performance using variables available at the end of double lung transplantation. The implementation of strategies adapted to modifiable variables could make it possible to limit the occurrence of a PGD or its severity. [ABSTRACT FROM AUTHOR]