Effector role of neonatal hepatic CD8+ lymphocytes in epithelial injury and autoimmunity in experimental biliary atresia.
OBJECTIVE
Lymphocytes populate the livers of infants with biliary atresia, but it is unknown whether neonatal lymphocytes regulate pathogenesis of disease. Here, we investigate this question by examining the role of T lymphocytes in the destruction of extrahepatic bile ducts of neonatal mice using an experimental model of biliary atresia.


METHODS
Inoculation of neonatal mice with rhesus rotavirus followed by multistaining flow cytometry to quantify expression of interferon-gamma by hepatic lymphocytes, and real-time polymerase chain reaction for mRNA expression of pro-inflammatory cytokines. This was followed by determining the consequences of antibody-mediated depletion of lymphocyte subtypes on the development of biliary obstruction, and coculture and cell transfer experiments to investigate the effector role of lymphocyte subtypes on neonatal biliary disease.


RESULTS
Rotavirus infection results in overexpression of interferon-gamma by neonatal hepatic T cells. Among these cells, depletion of CD4(+) cells did not change the course of inflammatory injury and obstruction of neonatal bile ducts. In contrast, loss of CD8(+) cells remarkably suppressed duct injury, prevented luminal obstruction, and restored bile flow. Coculture experiments showed that rotavirus-primed, but not naïve, CD8(+) cells were cytotoxic to cholangiocytes. In adoptive transfer experiments, we found that primed CD8(+) cells preferentially homed to extrahepatic bile ducts of neonatal mice and invaded their epithelial lining.


CONCLUSIONS
Primed neonatal CD8(+) cells can activate a pro-inflammatory program, target diseased and healthy duct epithelium, and drive the phenotypic expression of biliary atresia, thus constituting a potential therapeutic target to halt disease progression.
Shivakumar
Pranavkumar
P
Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, USA.
Sabla
Gregg
G
Mohanty
Sujit
S
McNeal
Monica
M
Ward
Richard
R
Stringer
Keith
K
Caldwell
Charles
C
Chougnet
Claire
C
Bezerra
Jorge A
JA
D019264:Adoptive Transfer; D000818:Animals; D000831:Animals, Newborn; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology / Q000821:virology; D001656:Biliary Atresia / Q000276:immunology* / Q000473:pathology* / Q000821:virology; D017252:CD3 Complex / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000637:transplantation / Q000821:virology; D016827:CD8 Antigens / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000637:transplantation / Q000821:virology; D002779:Cholestasis / Q000276:immunology / Q000473:pathology; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000276:immunology / Q000473:pathology; D000939:Epitopes; D005260:Female; D005434:Flow Cytometry; D007371:Interferon-gamma / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011247:Pregnancy; D012400:Rotavirus Infections / Q000150:complications / Q000276:immunology*
D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D000939:Epitopes; D007371:Interferon-gamma