Anti-BST2 Monoclonal antibody, clone 37G9

Bone marrow stromal antigen 2 (BST2)/Tetherin is an antiviral factor that blocks the release of enveloped virions from infected cells. Recent data suggest that efficient BST2 antagonism was a prerequisite for the global spread of HIV/AIDS. Most simian immunodeficiency viruses (SIVs), including the direct precursors of HIV, use their Nef protein to antagonize BST2 of their respective host species. Human BST2, however, contains a five amino acid deletion in its cytoplasmic domain that confers resistance to Nef. Thus, this antiviral factor constitutes a major barrier to effective zoonotic transmissions of SIVs to humans. Here, we show that this protective deletion has already been present in Neanderthal and Denisovan BST2 and thus evolved at least 800,000 years ago. This ancient origin helps to explain why effectively spreading zoonotic transmissions of SIVs to humans have been rare, although SIVs are widespread in African non-human primates and humans must have been exposed to these viruses many times. Hum Mutat 32: 1243-1245, 2011. (C) 2011 Wiley Periodicals, Inc.

Glioblastoma multiforme (grade IV astrocytoma) is a highly malignant brain tumor with poor treatment options and an average lifespan of 15 months after diagnosis. Previous work has demonstrated that BST2 (bone marrow stromal cell antigen 2; also known as PDCA-1, CD137 and HM1.24) is expressed by multiple myeloma, endometrial cancer and primary lung cancer cells. BST2 is expressed on the plasma membrane, which makes it an ideal target for immunotherapy. Accordingly, several groups have shown BST2 mAb to be effective for targeting tumor cells. In this report, we hypothesized that BST2 is expressed in human and mouse brain tumors and plays a critical role in brain tumor progression. We show that BST2 expression is upregulated at both the mRNA and protein level in high grade when compared to low grade human astrocytoma (p<0.05). To test the relevance of BST2, we utilized the intracranially (IC)-injected GL261 cell-based malignant brain tumor mouse model. We show that BST2 mRNA expression is increased in mouse brain IC-injected with GL261 cells, when compared to mouse brain IC-injected with saline at 3 weeks postoperative (p<0.05). Furthermore, BST2 immunofluorescence predominantly localized to mouse brain tumor cells. Finally, mice IC-injected with GL261 cells transduced with shRNA for BST2 +/- preincubated with BST2 mAb show no difference in overall lifespan when compared to mice IC-injected with GL261 cells transduced with a scrambled shRNA +/- preincubated with BST2 mAb. Collectively, these data show that while BST2 expression increases during brain tumor progression in both human and mouse brain tumors, it has no apparent consequences to overall lifespan in an orthotopic mouse brain tumor model. (C) 2011 Elsevier Inc. All rights reserved.