Use of a Lymph-Node Explant Culture System from California Sea Lions to Study Phocine Distemper Virus
- Infectious disease
Abstract
Phocine distemper virus (PDV) is a significant cause of mortality for phocid seals; however, the susceptibility of otariids to this virus is poorly understood. The authors used a lymph-node explant culture system from California sea lions (Zalophus californianus, CSL) to investigate: (1) the role of signaling lymphocyte activation molecule (SLAM) and nectin-4 in PDV infection and their cellular expression patterns, (2) if PDV induces transcriptional regulation of cell-entry receptors, and (3) the involvement of apoptosis in PDV infection. PDV replicated in the lymph-node explants with peak replication 3 days post-infection (dpi), but the replication was not sustained 4 to 5 dpi. The PDV+ cells co-localized SLAM and nectin-4. These cells expressed IBA1, indicating a histiocytic lineage. Comparison of receptor expression between infected and mock-infected lymph nodes suggested transcriptional downregulation of both receptors during the initial stage of infection and upregulation during the late stage of infection, but the values lack of statistical significance. Cleaved caspase-3+ cells were slightly increased in the infected lymph nodes compared with the mock-infected lymph node from 1 to 4 dpi, but without statistical significance, and a few apoptotic cells co-expressed PDV. The results suggest that lymph-node explants might be an important model to study PDV pathogenesis. CSLs have the potential to be infected with PDV, as they express both cell-entry receptors in histiocytes. The lack of statistical significance in the PDV replication, transcriptional regulation of viral receptors, and changes in apoptosis suggest that although CSL might be infected by PDV, they might be less susceptible than phocid species.
Gonzales-Viera, O., Goldstein, T., Duignan, P., Eiamcharoen, P., Keel, M.K., 2023. California sea lion (Zalophus californianus) lymph-node explant reveals involvement and possible transcriptional regulation of SLAM and nectin-4 during phocine distemper virus infection. Veterinary Pathology 2023;0(0).
Meet The Experts
{"image":"\/People\/Portrait\/cropped-images\/Padraig Duignan-0-56-635-496-1601760621.jpg","alt":"Padraig Duignan","title":"P\u00e1draig Duignan","text":"Director of Pathology","link_url":"https:\/\/www.marinemammalcenter.org\/person\/padraig-duignan","link_text":"Read Bio"}
Related Publications
{"image":"\/Animals\/Wild\/Other species\/nz-sea-lion-shutterstock.jpg","alt":"New Zealand sea lion","title":"Causes of Death in Two Populations of New Zealand Sea Lions","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/causes-of-death-in-two-populations-of-new-zealand-sea-lions","label":"Research Paper"}
{"image":"\/Animals\/Patients\/California sea lions\/csl-by-bill-hunnewell-c-the-marine-mammal-center-6.jpg","alt":"California sea lions","title":"Zoonotic Bacteria Persistence and Susceptibility","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/zoonotic-bacteria-persistence-and-susceptibility","label":"Research Paper"}
{"image":"\/Animals\/Patients\/California sea lions\/cropped-images\/csl-photo-by-bill-hunnewell-c-the-marine-mammal-center-1-0-0-2358-1722-1600891644.jpg","alt":"California sea lions","title":"Emerging Viruses in Marine Mammals","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/emerging-viruses-in-marine-mammals","label":"Research Paper"}
{"image":"\/Animals\/Patients\/California sea lions\/csl-photo-by-bill-hunnewell-c-the-marine-mammal-center-12.jpg","alt":"two California sea lions","title":"Multi-Phase Muscle Breakdown in California Sea Lions","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/multi-phase-muscle-breakdown-in-california-sea-lions","label":"Research Paper"}
Recent News
{"image":"\/People\/Action\/Veterinary care\/cropped-images\/Harris_Green turtle_TMMC-0-0-1270-992-1767649941.jpg","alt":"Heather Harris","title":"Seattle Aquarium Awards Dr. Heather Harris With Prestigious Conservation Research Award","link_url":"https:\/\/www.marinemammalcenter.org\/news\/seattle-aquarium-awards-dr-heather-harris-with-prestigious-conservation-research-award","label":"In the News","date":"2026-01-05 04:48:00"}
Seattle Aquarium Awards Dr. Heather Harris With Prestigious Conservation Research Award
January 5, 2026
Read More{"image":"\/People\/Action\/Veterinary care\/cropped-images\/harris-teaching-tube-feeding-0-0-1270-992-1767650122.jpg","alt":"A veterinarian and two trained volunteers tube feed an elephant seal pup.","title":"Training College Students in Marine Mammal Health","link_url":"https:\/\/www.marinemammalcenter.org\/news\/training-college-students-in-marine-mammal-health","label":"News Update","date":"2026-01-05 04:48:00"}
{"image":"\/Animals\/Patients\/Harbor seals\/2013\/cropped-images\/hs-bogey-photo-by-Ingrid-Overgard-c-the-marine-mammal-center-382-0-2914-2276-1605061447.jpg","alt":"harbor seal Bogey","title":"Top Eco Friendly Valentine\u2019s Day Gifts","link_url":"https:\/\/www.marinemammalcenter.org\/news\/top-eco-friendly-valentines-day-gifts","label":"News Update","date":"2026-01-01 01:00:00"}
{"image":"\/Animals\/Patients\/Harbor seals\/2020\/cropped-images\/hs-barnwood-by-bill-hunnewell-c-the-marine-mammal-center-315-0-3299-2577-1607370547.jpg","alt":"harbor seal Barnwood","title":"Last-Minute Gift Guide \u2013 Top Gifts that Give Back to Marine Animals","link_url":"https:\/\/www.marinemammalcenter.org\/news\/last-minute-gift-guide","label":"News Update","date":"2025-12-18 01:00:00"}
Last-Minute Gift Guide – Top Gifts that Give Back to Marine Animals
December 18, 2025
Read More