Jun-You Li

Antigenic heterogeneity among phylogenetic clusters of influenza D viruses

Influenza (flu) D virus, a possible causative agent of bovine respiratory disease, is genetically classified into three clusters: D/OK-, D/660-, and D/Japan-lineages. To evaluate antigenic heterogeneity among these clusters, we compared antibody titers to each lineage virus using bovine sera collected over time following virus infection. Antibody titers to D/Japan-lineage virus rose rapidly in the acute phase of infection, and were 4 times higher than those to the other clustered viruses. In the later phase of infection, titers to D/Japan-lineage virus were equivalent to those to D/OK-lineage virus, and still higher than those to D/660-lineage virus. These results suggest the existence of common and lineage-specific antigenic epitopes in the hemagglutinin-esterase-fusion protein of flu D viruses.

Expression of uterine lipocalin 2 and its receptor during early- to mid-pregnancy period in mares

From previous cDNA subtraction studies analyzing gene expression in equine endometrium, high lipocalin 2 (LCN2) mRNA expression was found in the gravid endometrium. In the uterus, LCN2 may transport hydrophobic molecules and siderophores with iron, or may form a complex with another protein, however, the expression of uterine LCN2 beyond day 20 of equine pregnancy and its receptor has not been characterized. To study the expression and potential roles of uterine LCN2 from pre-implantation to mid-gestation period, stage-specific endometrial samples were obtained from day 13 (day 0 = ovulation) cyclic and days 13, 19, 25, and 60 to 131 pregnant mares. Expression of LCN2 mRNA increased in day 19 gravid endometrium and was abundant from day 60 onward. The expression of LCN2 mRNA was localized to the glandular epithelium. LCN2 protein was detected in day 25 gravid endometrium and luminal fluid, and the protein was localized to the glandular epithelium and luminal cavity, whereas LCN2 receptor expression was found in luminal and glandular epithelium and trophectoderm throughout the experimental period. The presence of matrix metalloproteinase-9 (MMP9) was also examined because MMP9 is known to form a complex with LCN2. Although MMP9 and LCN2 were both found in luminal fluid from day 25 pregnant uterus, the complex of these proteins was not detected. Localization of the receptor in the trophectoderm suggests that endometrial LCN2 could play a role in carrying small substances from the mother to fetus in the equine species.

Abdominal hamartoma with pancreatic and hepatic differentiation in a sow

A 7-year-old Duroc sow exhibited emaciation, loss of appetite and rapid breathing, and was euthanized. Histopathological examination revealed mild to moderate fibrosis of the heart, cystic kidneys and ulcerative enteritis associated with Balantidium infection. Additionally, a small nodule was incidentally found in the peripancreatic fat tissue. The nodule consisted of disarranged cellular components: pancreatic islet cells (either insulin-, glucagon- or somatostatin-positive), pancreatic acinar cells, hepatocytes (human hepatocyte-positive) and ductal cells (cytokeratin 19-positive). Some of the human hepatocyte-positive cells were also positive for chromogranin A and cytokeratin 7, indicating that they were hepatic progenitor cells. The nodule was therefore diagnosed as hamartoma, probably originating from a fragment of the caudal verge of the liver bud, which contains hepatic and pancreatic progenitors.