4 mAb therapy (Anonymous, 2012a and Guest, 2012). There have been no adverse effects observed or reported in these cases. Initial immunization learn more strategies using the henipavirus G or F viral glycoproteins

were first evaluated using recombinant vaccinia viruses providing evidence that complete protection from disease was achievable by eliciting an immune response to the Nipah virus envelope glycoproteins (Guillaume et al., 2004). Other studies using recombinant canarypox-based vaccine candidates for potential use in pigs have also been carried out (Weingartl et al., 2006). To date, the most widely evaluated henipavirus vaccine antigen has been a subunit, consisting of a recombinant soluble and oligomeric form of the G glycoprotein (sG) of Hendra virus (HeV-sG) (Bossart et al., 2005). The HeV-sG subunit vaccine (Fig. 1) is a secreted version of the molecule in which the transmembrane and cytoplasmic tail domains have been deleted from the coding sequence. HeV-sG is produced in mammalian cell culture expression systems and is properly N-linked glycosylated and retains many native characteristics including its oligomerization into dimers and tetramers, ability to bind ephrin receptors and elicit potent cross-reactive (Hendra and Nipah virus) neutralizing antibody responses (reviewed in (Broder et al., 2012)) Table

2. Studies showing the HeV-sG subunit immunogen as a successful vaccine against lethal Hendra virus Epigenetics inhibitor Endonuclease or Nipah virus challenge have been carried out in

the cat (McEachern et al., 2008 and Mungall et al., 2006), ferret (Pallister et al., 2011b) and nonhuman primates (Bossart et al., 2012) (Table 2), and details of the results from these studies have been reviewed elsewhere (Broder et al., 2012). The success of the HeV-sG vaccine-mediated protection observed in multiple animal challenge models led to the consideration of the HeV-sG as a safe and effective vaccine for horses against Hendra virus infection in Australia following a human fatality in 2009 and the human exposure cases in 2010 discussed above. The adopted equine vaccination strategy was to both prevent infection in horses and thus ameliorate the risk of Hendra virus transmission to people. A series of horse HeV-sG vaccination and Hendra virus challenge studies have been carried out in Australia; at the high containment biological safety level 4 (BSL-4) facilities of the Animal Health Laboratories (AAHL), Commonwealth Scientific and Industrial Research Organisation (CSIRO), in Geelong. The development of HeV-sG as an equine vaccine against Hendra virus was a collaborative research program between the Uniformed Services University of the Health Sciences, the Henry M. Jackson Foundation, the AAHL and Pfizer Animal Health (now Zoetis, Inc.). Findings from these initial studies were reported at Australian Veterinary Association, Annual Conference in Adelaide, in May 2011 (Balzer, 2011).