Abstract
Adaptive immunity requires that a single lymphocyte gives rise to both effector cells and memory cells. The authors of this paper demonstrated how this occurs by asymmetric division of the lymphocyte which results in unequal partitioning of proteins in the two daughter cells. This process is dependent on sustained interaction between the T cell and the antigen-presenting cell prior to the first T cell division. Furthermore, they showed that the first daughter cells exhibited different phenotypic and functional properties, consistent with their diverging roles as effector and memory cells. These observations will enhance our understanding of lymphocyte biology and may be extended to hematopoietic and cancer stem cells.
Chang JT, Palanivel VR, Kinjyo I, et al. Asymmetric T lymphocyte division in the initiation of adaptive immune responses. Science
The domestic dog exhibits tremendous variability in body size, ranging from the tiny Chihuahua to the massive Great Dane. To investigate the genetic basis for this diversity, Elaine Ostrander's group performed a genome-wide scan and identified a quantitative trait locus on canine chromosome 15. A closer look at this region implicated the Insulin-Like Growth Factor 1 (IGF1) gene as having a major role in determining body size in small dogs. The investigators found a single-nucleotide polymorphism in IGF1 that is common to all small breeds, but is not present large breeds. This study demonstrates the ability to find a gene responsible for morphology in the dog without doing extensive genetic crosses or using other breeding strategies.
Sutter NB, Bustamante CD, Chase K, et al. A single IGF1 allele is a major determinant of small size in dogs. Science
Urinary bladder tumors in cattle are associated chronic enzootic hematuria secondary to ingestion of bracken fern. The resulting tumors can be of epithelial or mesenchymal origin, with the latter usually being hemangiomas or hemangiosarcomas. Bovine papillomavirus-2 (BPV-2) DNA is present in non-neoplastic bovine urothelium, but the BPV-2 E5 oncoprotein is only expressed in neoplastic epithelial cells. This group investigated whether BPV-2 oncoproteins are involved in mesenchymal tumors of the bovine urinary bladder. They report that BPV-2 DNA was present in all 27 vascular tumors examined. The E5 and E7 oncoproteins were expressed in 96% and 74% of the tumors, but not in the normal endothelial cells. Furthermore, E5 co-localized with the platelet-derived growth factor beta receptor, which is thought to play a role in cellular transformation. These results support a possible role for BPV-2 in bovine mesenchymal bladder tumors.
Borzacchiello G, Russo V, Spoleto C, et al. Bovine papillomavirus type-2 DNA and expression of E5 and E7 oncoproteins in vascular tumours of the urinary bladder in cattle. Cancer Letters
Macrophages are usually present in renal lesions of diabetic nephropathy; however their role in the pathogenesis and/or progression of this condition is unknown. This was investigated in db/db mice by blocking chemokine receptor 1 (CCR1) which recruits macrophages to the renal interstitium. Administration of the CCR1 antagonist BL5923 resulted in markedly decreased numbers of interstitial macrophages, reduced numbers of Ki-67 positive tubular epithelial and interstitial cells, decreased tubular atrophy and decreased interstitial fibrosis. Glomeruli appeared unaffected. Compared to nontreated mice, the kidneys of treated mice had decreased expression several chemokines as well as decreased TGF-beta1 and collagen I-alpha1. The authors suggest that macrophages likely play a central role in the pathogenesis of diabetic nephropathy and that therapy with BL5923 warrants further investigation.
Ninichuk V, Khandoga AG, Segerer S, et al. The role of interstitial macrophages in nephropathy of type 2 diabetic db/db mice. Am J Pathol