Anti-HSPA5 monoclonal antibody, clone 5F22

Development of novel strategies targeting the highly virulent ebolaviruses is urgently required. A proteomic study identified the ER chaperone HSPA5 as an ebolavirus-associated host protein. Here, we show using the FISPA5 inhibitor (-)- epigallocatechin gallate (EGCG) that the chaperone is essential for virus infection, thereby demonstrating a functional significance for the association. Furthermore, in vitro and in vivo gene targeting impaired viral replication and protected animals in a lethal infection model. These findings demonstrate that HSPA5 is vital for replication and can serve as a viable target for the design of host-based countermeasures. Published by Elsevier B.V.

The sperm plasma membrane is known to be critical to fertilization and to be highly regionalized into domains of head, mid- and principal pieces. However, the molecular composition of the sperm plasma membrane and its alterations during genital tract passage, capacitation and the acrosome reaction remains to be fully dissected. A two-dimensional gel-based proteomic study previously identified 98 human sperm proteins which were accessible for surface labelling with both biotin and radioiodine. In this report twelve dually labelled protein spots were excised from stained gels or PDVF membranes and analysed by mass spectrometry (MS) and Edman degradation. Seven members from four different heat shock protein (HSP) families were identified including HYOU1 (ORP150), HSPC1 (HSP86), HSPA5 (Bip), HSPD1 (HSP60), and several isoforms of the two testis-specific HSP70 chaperones HSPA2 and HSPA1L. An antiserum raised against the testis-specific HSPA2 chaperone reacted with three 65 kDa HSPA2 isoforms and three high molecular weight surface proteins (78-79 kDa, 84 kDa and 90-93 kDa). These proteins, together with seven 65 kDa HSP70 forms, reacted with human anti-sperm IgG antibodies that blocked in vitro fertilization in humans. Three of these surface biotinylated human sperm antigens were immunoprecipitated with a rabbit antiserum raised against a linear peptide epitope in Chlamydia trachomatis HSP70. The results indicate diverse HSP chaperones are accessible for surface labelling on human sperm. Some of these share epitopes with C. trachomatis HSP70, suggesting an association between genital tract infection, immunity to HSP70 and reproductive failure. (C) 2009 Elsevier Ireland Ltd. All rights reserved.