The active role played by xenogeneic endothelial cells in the indirect presentation pathway is not lymphocyte trans-co-stimulation.

The human CD4+ T lymphocyte response to major histocompatibility complex (MHC) class II-negative porcine endothelial cells is dependent on the presence of human monocytes through a human leukocyte antigen (HLA) class II-restricted indirect presentation pathway. Because the role of porcine endothelial cells had been previously shown to do more than simply supply xenopeptides, co-stimulatory signals were analysed. Endothelial cells were shown to express the CD54, CD58, CD59 and CD86 transcripts; however, no membrane B7 molecule could be detected.

Porcine CD58: cDNA cloning and molecular dissection of the porcine CD58-human CD2 interface.

The porcine ligands of human CD2 remain unknown in xenotransplantation despite being an important pathway of T cell costimulation. Of the two main candidates, i.e.

Analysis of human CD4 T lymphocyte proliferation induced by porcine lymphoblastoid B cell lines.

Background: This study was undertaken to characterize the two porcine lymphoblastoid cell lines L23 and L35, derived from a pig inoculated by the retrovirus Tsukuba-1, and to determine how they induce a strong human lymphocyte proliferation.

Methods: Phenotypic characterization was performed by flow cytometry and reverse transcriptase-polymerase chain reaction analyses. Xenogeneic mixed lymphocyte reactions (XMLR) were performed using unfractionated human peripheral blood mononuclear cells (huPBMC) and purified CD4+ T lymphocytes as responding cells, in the presence of blocking antibodies and fusion proteins.