Tolerogenic properties of lymphatic endothelial cells are controlled by the lymph node microenvironment.

Peripheral self-tolerance eliminates lymphocytes specific for tissue-specific antigens not encountered in the thymus. Recently, we demonstrated that lymphatic endothelial cells in mice directly express peripheral tissue antigens, including tyrosinase, and induce deletion of specific CD8 T cells via Programmed Death Ligand-1 (PD-L1). Here, we demonstrate that high-level expression of peripheral tissue antigens and PD-L1 is confined to lymphatic endothelial cells in lymph nodes, as opposed to tissue (diaphragm and colon) lymphatics.

Alternative splicing of the trout Pax5 gene and identification of novel B cell populations using Pax5 signatures.

Pax5 is an alternatively spliced transcription factor that regulates B cell development and activation. The function of specific Pax5 isoforms is unknown. Here we report the existence of seven alternatively spliced isoforms of Pax5 in the rainbow trout.

Sockeye salmon retain immunoglobulin-secreting plasma cells throughout their spawning journey and post-spawning.

Antibody-producing plasma cells are a major source of protective immunity in vertebrates, including salmon. During the spawning phase, salmon undergo drastic, hormonally driven changes in their physiology, including elevated levels of cortisol, which are known to suppress the immune system. As adult fish need to survive their long journey to the spawning grounds, we hypothesized that humoral immunity, in the form of IgM-secreting plasma cells, remains functional until post-spawning.