Relationship between liver disorders and protection against Eimeria stiedai infection in rabbits immunized with soluble antigens from the bile of infected rabbits.
Soluble antigens exist in the bile of rabbits infected with Eimeria stiedai (E. stiedai) in the acute phase, and rabbits immunized with the antigens show resistance against the infection. In this study, the liver function of rabbits immunized either with the soluble antigens or PBS were examined following the parasite challenge. Rabbits immunized with PBS shed a number of oocysts and showed an increase in r-glutamyltransferase (GGT) activity and a decrease in blood Indocyanine green (ICG) clearance. However, rabbits immunized with the soluble antigens shed a lower number of oocysts and showed a transient increase of alanine-aminotransferase (ALT) activity on Day 8 post-challenge (p.c.). The blood Indocyanine green clearance of the rabbits showed no change throughout the experiment. By histopathological observation of the liver, a number of merozoites were found in the biliary ducts on Day 8 post-challenge in the non-immunized rabbits. In contrast, a number of lymphocytes and neutrophilic leukocytes assembled around the biliary ducts of the immunized rabbits, but few parasites were found there on Day 8 post-challenge. These results suggest that the soluble antigens stimulate local immune reactions, for example around the biliary ducts, resulting in elimination of the parasite's development.
Hanada
S
S
Department of Veterinary Physiology, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro 080-8555, Japan.
Omata
Y
Y
Umemoto
Y
Y
Kobayashi
Y
Y
Furuoka
H
H
Matsui
T
T
Maeda
R
R
Saito
A
A
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D001646:Bile / Q000276:immunology / Q000469:parasitology; D003048:Coccidiosis / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D004396:Coloring Agents; D004539:Eimeria / Q000276:immunology*; D005243:Feces / Q000469:parasitology; D005260:Female; D006651:Histocytochemistry / Q000662:veterinary; D007116:Immunization, Passive / Q000662:veterinary; D007208:Indocyanine Green; D008107:Liver Diseases / Q000276:immunology* / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D010270:Parasite Egg Count / Q000662:veterinary; D011817:Rabbits / Q000469:parasitology*; D013047:Specific Pathogen-Free Organisms; D005723:gamma-Glutamyltransferase / Q000097:blood
D000953:Antigens, Protozoan; D004396:Coloring Agents; D005723:gamma-Glutamyltransferase; D000410:Alanine Transaminase; D007208:Indocyanine Green