Baculoviruses inactivation

A second milestone in the production of viral antigens was the development of the technology associated with insect cells - the baculovirus expression system. The Autographa californica baculovirus produces viral particles as a part of its life cycle. These particles accumulate in the polyhedrin protein matrix, which confers protection from inactivation due to environmental factors. The polyhedrin is produced in large amounts... 

Numerous studies have investigated effects of UV light inactivation of baculoviruses [12, 32, 34, 70, 84], Generally, the virucidal effects of UV radiation is rapid and has been partly attributed to the adverse affects on DNA or virus-associated structural proteins [42],... 

Surface moisture may influence the susceptibility of baculovirus deposits to inactivation by ultraviolet light. Consistent with the studies on VACV, it was observed that PbGV inactivated more rapidly in wet vims films exposed to UV radiation than in dry films [19], as in the cases of TnNPV [58] and HzSNPV [55], These findings suggest that surface moisture favors the inactivation of baculovimses exposed to UV radiation. 

The virucidal effects of pH have been studied more extensively for baculoviruses. Ignoffo and Garcia [48] observed a significant reduction in virus activity for inclusion bodies exposed at pH 1.2 and pH 12.4. Similar results were reported for HzSNPV at pH 2 and pH 12 [36], Virus inactivation was recorded at 50% and 88% after 30 min and 24 h respectively, suspended at pH 2 in 1.0 M phosphate buffer. Comparatively, vims suspended at pH 12, in 1.0 M phosphate buffer, was inactivated by 40% and 92% after 30 min and 24 h respectively. Similarly, TnNPV in soil exposed to low pH (4.83-5.22) is rapidly inactivated over a month [113],... 

Effect of moisture or humidity. Based on a paucity of research, the most constructive generalization is to state VACV and baculoviruses are susceptible to inactivation under similar conditions of high moisture and RH. A greater loss of VACV viability was observed in aerosols at 80% RH when compared to lower RH conditions <50% [37], Similar results have been reported by Sidwell et al. [100], Furthermore, McDevitt et al. [82] demonstrated the survival of aerosolized VACV in the presence of UVC is significantly influenced by relative humidity. As the moisture content (RH) increases, VACV becomes more susceptible to UVC inactivation. Comparably,... 

Ignoffo, C.M., Rice, W.C., and McIntosh, A.H., 1989. Inactivation of nonoccluded and occluded baculovimses and baculovirus-DNA exposed to simulated sunlight. Environ. Entomol., 18 177-183. 

This 35-kDa protein was confirmed as the vCKBP by pierforming the same assays with two recombinant Ws, W RPVA35 and W Lister A35 from which the fully functional gene had been inactivated by insertion of the LacZ gene. Neither of these viruses produced a secreted protein that bound to I-chemokine. Furthermore, when the W Lister 35-kDa ORF was expressed with a G-terminal 6xHis-tag in the baculovirus system, or as an Fc fusion protein from stably transfected mammalian cells, binding of the recombinant products to... 

Commercial adjuvants were tested for /feSNPV activity improvement and Coax and Gustoi did not provide UV protection for the zSNPV baculovirus (58) (Table 2). They compared inactivation of a standard acetone-dried preparation of /feSNPV diseased larvae mixed with 20% lactose (IMC-01) a commercial wettable powder (SAN-240-WP, Sandoz), and a water-based formulation (SAN-24S0-WDC, Sandoz). They added a liquid-flowable material from Sandoz-Wander Inc., in the final spray-tank, at 10% W/V. San-240-WP formulation without adjuvant protected. zSNPV activity similarly dian die formulations with adjuvants, after 4 h exposure to simulated solar radiation (98.4, 113.1 and 108.8 % OAR, respectively whereas IMC-01 and no-adjuvant SAN-240-WDC lost significantly activity (9.1 and 39.0 % OAR, respectively). The use of a liquid-flowable material enhanced the //zSNPV activity 2-11 times after artificial sunlight exposure (50) (Table 4). 

Ignoffo, C. M. Garda, C. Antioxidants and oxidative enzyme effects on the inactivation of inclusion bodies of Heliothis baculovirus by simulated sunlight-UV. Environ. Entomol. 1994.23,1025-1029. 

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