Effects of Gamma Irradiation of Human Serum Samples from rVSVΔG-ZEBOV-GP (V920) Ebola Virus Vaccine Recipients on Plaque-Reduction Neutralization Assays.

Gamma irradiation (GI) is included in the CDC guidance on inactivation procedures to render a group of select agents and toxins nonviable. The Ebola virus falls within this group because it potentially poses a severe threat to public health and safety. To evaluate the impact of GI at a target dose of 50 kGy on neutralizing antibody titers induced by the rVSVΔG-ZEBOV-GP vaccine (V920), we constructed a panel of 48 paired human serum samples (GI-treated versus non-GI-treated) from healthy participants selected from a phase 3 study of V920 (study V920-012; NCT02503202). Neutralizing antibody titers were determined using a validated plaque-reduction neutralization test. GI of sera from V920 recipients was associated with approximately 20% reduction in postvaccination neutralizing antibody titers. GI was not associated with any change in pre-vaccination neutralizing antibody titers.

Toxicity and immunogenicity of Crotalus durissus terrificus venom treated with different doses of gamma rays.

Crotalus durissus terrificus venom (CDT venom) was irradiated with four different doses of gamma rays (2, 3, 5 and 10 kGy) from a 60Co source and their structural, toxic and immunogenic properties were analysed. Venom irradiated with 2 and 3 kGy were, respectively, 2.7 and 13.5 times less toxic than the native one, whereas the 5 or 10 kGy irradiated venom were at least 100 times less toxic than nonirradiated venom. Irradiated venom with all doses were immunogenic and the antibodies elicited by them were able to recognise the native venom in ELISA. However the toxoid produced with 2 kGy irradiation dose had its immunogenicity improved. Antisera raised against this toxoid had a higher neutralising capacity than those produced against the native venom. Irradiation of venom with 2 kGy dose was the most effective to inactivate the CDT venom toxicity and improve its immunogenicity.

[Comparative radioprotective efficacy of native and irradiated in vitro immunoglobulins from horse serum]. / Sravnitel'naia protivoluchevaia éffektivnost' nativnogo i obluchennogo in vitro immunoglobulinov syvorotki krovi loshadei.

The therapeutic application of native and in vitro exposed (20000 Gy immunoglobulins of horse blood serum increased the survival of irradiated (LD75-95) animals, normalized the quantitative and qualitative status of the small intestine microflora and prevented enterobacteria from penetrating the internal organs. The irradiated preparations were more active than native ones.

Sheets obtained by radiation polymerization for enzyme immunoassay.

Immobilized anti-alpha-fetoprotein sheets, which were attached to sticks, for enzyme immunoassay of alpha-fetoprotein were prepared by radiation polymerization of hydrophilic monomers. The relationship between the preparation conditions and the activity of the sheets was studied. The activity varied with monomer concentration, hydrophilicity of polymer matrix, the amount of coating solution, and antibody concentration. The sheets obtained at relatively low monomer and antibody concentrations appeared to give a high activity. It was found that the sheets are applicable for the enzyme immunoassay of alpha-fetoprotein with high sensitivity.

Bovine babesiosis: steps towards an irradiated vaccine.

A series of experiments leading towards the field trial of an irradiated blood-derived vaccine against Babesia divergens, common cause of redwater in cattle in Europe, is described. Initially a number of isolates of B. divergens were made from the blood of sick animals in a variety of localities in the british Isles. These isolates were cryopreserved and then characterised by inoculation into groups of spenectomised Friesian calves, whose reactions were statistically analysed. Attempts were made to prepare a vaccine against B. divergens infection using diluted infected blood, but when these failed it was found that irradiation of infected blood within the range of 24 to 32 kilorads and its intravenous inoculation into calves produced the required immune response without pathogenic effects. An irradiated blood-derived vaccine produced by the irradiation of infected blood at 25 or 30 kilorads was used in a field trial in Ireland, and vaccinated calves were protected against a field challenge which caused redwater in 10 control cattle, six of which had severe reactions.