Steller sea lion (Eumetopias jubatus) pups undergo a decrease in circulating white blood cells and the ability of T cells to proliferate during early postnatal development.
Postnatal changes in circulating immune components and peripheral blood mononuclear cell (PBMC) proliferation were assessed in Steller sea lion pups (SSL; Eumetopias jubatus). Blood samples were collected for complete blood cell counts including total and differential white blood cell (WBC) counts from 46 pups ranging in age from 5 to 38 days old. Total WBC and neutrophil counts decreased in association with increased age of the pups. The ability of PBMC to proliferate was assessed by in vitro exposure to concanavalin A (ConA) or lipopolysaccharide (LPS) in 21 pups ranging in age from 7 to 32 days old. All SSL pups responded to in vitro stimulation with ConA and LPS 055:B5 indicating peripheral T and B cells are capable of responding to an antigenic challenge. ConA-induced T cell proliferation decreased with age while there was no change in spontaneous proliferation of PBMC or B cells exposed to LPS. The decreases in total WBC, neutrophil counts and T cell proliferation indicates that SSL undergo a period of postnatal development in cell-mediated immune function which is comparatively longer than phocid pups and consistent with other otariids.
Keogh
Mandy J
MJ
School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, AK 99775-7220, USA. mandyjkeogh@gmail.com
Maniscalco
John M
JM
Atkinson
Shannon
S
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008297:Male; D046070:Sea Lions / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D006854:Hydrocortisone