Subunit immunogen of the tick-borne encephalitis virus. The isolation of glycoprotein V3 from 2 types of the tick-borne encephalitis virus and a study of its amino acid composition

An effective method for isolation of the membrane structural E protein, the so-called V3 glycoprotein, is described. Preliminary data of its amino acid composition have been obtained.     

Further development of a new transgenic mouse test for the evaluation of the immunogenicity and protective properties of inactivated poliovirus vaccine

Recently, we developed and optimized a new method for the evaluation of the protective properties of serotype 2 inactivated poliovirus vaccines (IPV). The method is based on the immunization and subsequent challenge of transgenic (Tg) mice susceptible to poliovirus. We describe a similar method for the assessment of the protectiveness of serotype 1 IPV and demonstrate that experimental IPV produced from attenuated Sabin strain (sIPV) of serotype 1 poliovirus induced serum neutralizing antibodies, immunoglobulin (Ig) G, IgM, and salivary IgA at titers comparable to those induced by conventional IPV (cIPV) produced from the wild-type Mahoney strain. In contrast to our previous results with serotype 2 sIPV, serotype 1 sIPV provided even better protection of Tg mice than cIPV against challenge with wild-type Mahoney strain.     

Cleavage of eukaryotic initiation factor eIF5B by enterovirus 3C proteases

The enteroviruses poliovirus (PV), Coxsackie B virus (CVB) and rhinovirus (HRV) are members of Picornaviridae that inhibit host cell translation early in infection. Enterovirus translation soon predominates in infected cells, but eventually also shuts off. This complex pattern of modulation of translation suggests regulation by a multifactorial mechanism. We report here that eIF5B is proteolytically cleaved during PV and CVB infection of cultured cells, beginning at 3 hours post-infection and increasing thereafter. Recombinant PV, CVB and HRV 3Cpro cleaved purified native rabbit eukaryotic initiation factor (eIF) 5B in vitro at a single site (VVEQG, equivalent to VMEQG479 in human eIF5B) that is consistent with the cleavage specificity of enterovirus 3C proteases. Cleavage separates the N-terminal domain of eIF5B from its essential conserved central GTPase and C-terminal domains. 3Cpro-mediated cleavage of eIF5B may thus play an accessory role in the shutoff of translation that occurs in enterovirus-infected cells.     

Fibroblast growth factor 4 and its novel splice isoform have opposing effects on the maintenance of human embryonic stem cell self-renewal

Human embryonic stem cells (HESCs) are unique in their capacity to self-renew while remaining pluripotent. This undifferentiated state must be actively maintained by secreted factors. To identify autocrine factors that may support HESC growth, we have taken a global genetic approach. Microarray analysis identified fibroblast growth factor 4 (FGF4) as a prime candidate for autocrine signaling. Furthermore, the addition of recombinant FGF4 to HESCs supports their proliferation. We show that FGF4 is produced by multiple undifferentiated HESC lines, along with a novel fibroblast growth factor 4 splice isoform (FGF4si) that codes for the amino-terminal half of FGF4. Strikingly, although FGF4 supports the undifferentiated growth of HESCs, FGF4si effectively counters its effect. Furthermore, we show that FGF4si is an antagonist of FGF4, shutting down FGF4-induced Erk1/2 phosphorylation. Expression analysis shows that both isoforms are expressed in HESCs and early differentiated cells. However, whereas FGF4 ceases to be expressed in mature differentiated cells, FGF4si continues to be expressed after cell differentiation. Targeted knockdown of FGF4 using small interfering RNA increased differentiation of HESCs, demonstrating the importance of endogenous FGF4 signaling in maintaining their pluripotency. Taken together, these results suggest a growth-promoting role for FGF4 in HESCs and a putative feedback inhibition mechanism by a novel FGF4 splice isoform that may serve to promote differentiation at later stages of development.     

WHO Working Group discussion on revision of the WHO recommendations for the production and control of poliomyelitis vaccines (oral): TRS Nos. 904 and 910. Report of Meeting held on 20-22 July 2010, Geneva, Switzerland

Oral poliomyelitis vaccine (OPV) is a critical part of the polio eradication programme. A high number of doses are administered each year with an impact on billions of citizens worldwide. It is therefore essential that written standards concerning OPV are up to date and widely available. The World Health Organization (WHO) publishes technical guidance on the quality, safety and efficacy of vaccines intended to assist national regulatory authorities (NRAs), national control laboratories (NCLs) and manufacturers. As part of its programme, on 20-22 July 2010 WHO convened a working group meeting to initiate the revision of the WHO recommendations on the production and control of OPV as presently outlined in the Technical Reports Series (TRS) issues Nos. 904 and 910 [1] and [2]. The attendees included experts from academia, NRAs/NCLs and industry involved in the study, manufacture, and authorization and testing/release of OPV from countries around the world including representatives from China, the European Union, Indonesia, Japan, Mexico, and the USA. The objective was to review the state of knowledge concerning production and control of OPV, with a focus on neurovirulence testing, to determine how the existing guidelines should be updated and what recommendations should be made for the future. The outcomes of this meeting will be taken into consideration in future revision of the WHO TRS.