Enzootic bovine leukosis in a 21-month-old Japanese Black cow with high susceptibility.

A 21-mo-old Japanese Black beef cow had swollen mandibular and superficial cervical lymph nodes. Fine-needle aspiration cytology of the superficial cervical lymph node revealed large lymphoblasts with mitoses present. The bovine leukemia virus (BLV) proviral load was relatively high, and phylogenetic analysis of the whole BLV genome classified the BLV strain as one with high viral replication activity. Genotyping of bovine leukocyte antigen genes indicated that the cow was susceptible to enzootic bovine leukosis (EBL). The bone morphogenetic protein 6 (BMP6) gene promoter region was hypermethylated. Monoclonal proliferation of B cells and monoclonal integration of the BLV provirus in the bovine genome were detected by a clonality test of B cells and an inverse PCR assay, respectively. At autopsy, generalized swelling of lymph nodes and spinal canal invasion by tumor tissue at vertebrae L5-6 were observed. Histologic analysis revealed diffuse proliferation of large round neoplastic cells that were positive for BLA36 and negative for CD3. The cow was definitively diagnosed with EBL based on these findings. Infection with a highly pathogenic strain of BLV, susceptibility of the BoLA-DRB3 alleles, and hypermethylation of the BMP6 gene may have contributed to the development of EBL in our case.

Oral Administration of Fucoidan Can Exert Anti-Allergic Activity after Allergen Sensitization by Enhancement of Galectin-9 Secretion in Blood.

A previous study revealed that fucoidan inhibited mast cell degranulation through the upregulation of galectin-9 in blood. The purpose of this study is to elucidate its mechanism using ovalbumin (OVA) induced anaphylaxis model mice (BALB/c, Female, 5-week-old) and mast cell line (RBL-2H3 cells). Oral administration of fucoidan after sensitization with OVA/Al(OH)3 inhibited reduction of rectal temperature induced by activation of mast cells. Fucoidan increased galectin-9 mRNA expression only in colonic epithelial cells. These results suggested that fucoidan could suppress the allergic symptoms in sensitized mice by inducing galectin-9 production from colonic epithelial cells. In addition, to check the influence of galectin 9 on the degranulation of mast cells, RBL-2H3 cell lines were treated directly with recombinant galectin-9. As expected, galectin-9 inhibited degranulation of RBL-2H3 cells pre-bound with IgE. Moreover, the residual amounts of IgE on RBL-2H3 cells were decreased by an addition of galectin-9. It was demonstrated that galectin-9 could remove IgE even if IgE was already bound to mast cells and suppress the mast cells degranulation induced by antigen. This study shows that fucoidan might become an effective therapeutic agent for patients already developed type I allergic diseases.

Disseminated thymic B-cell lymphoma in a Holstein heifer.

A 19-mo-old Holstein heifer was inactive and dyspneic. Physical examination revealed wheezing, exophthalmos, a cervical mass, and lymphadenopathy. Cytology of the cervical mass and lymph nodes showed predominantly large atypical lymphocytes. Lactate dehydrogenase and thymidine kinase activities were elevated. Although nested PCR for bovine leukemia virus (BLV) using blood was positive, quantitative PCR showed a low number of provirus copies. Autopsy revealed enlargement of most lymph nodes examined, as well as white masses of various sizes in muscles of the left hindlimb and thoracic and abdominal organs. Histopathology revealed severe infiltration with neoplastic lymphocytes in these organs. The cervical mass was immune-positive for B-cell markers. The final diagnosis was thymic B-cell lymphoma with BLV infection.