Effects of Three Types of Inactivation Agents on the Antibody Response and Immune Protection of Inactivated IHNV Vaccine in Rainbow Trout.

Infectious hematopoietic necrosis virus (IHNV) infects salmonid fish, resulting in high mortality and serious economic losses to salmonid aquaculture. Therefore, an effective IHNV vaccine is urgently needed. To select an inactivation agent for the preparation of an effective IHNV vaccine, rainbow trout were immunized with mineral oil emulsions of IHNV vaccines inactivated by formaldehyde, binary ethylenimine (BEI), or ß-propiolactone (BPL). The fish were challenged 8 weeks after vaccination, and their IgM antibody response and relative percent survival (RPS) were evaluated. The results show that formaldehyde, BEI, and BPL abolished IHNV HLJ-09 infectivity within 24, 48, and 24 h at final concentrations of 0.2%, 0.02%, and 0.01%, respectively. The mean levels of specific IgM, both in serum and mucus (collected from the skin surface and gills), for the three immunized groups (from high to low) ranked as follows: the BPL group, BEI group, and formaldehyde group. From weeks 5 to 9, the mean log2 serum titers of IgM in the BPL group were significantly higher compared with those of the other groups (p < 0.05) during the 9 weeks of observation after vaccination (immunized at weeks 0 and6). Mucus OD490 values of the BPL group were significantly higher compared with those of the other groups (p < 0.05) when reaching their peak at weeks 5 and 8, but the difference between the formaldehyde and BEI groups was not significant (p > 0.05). The BPL-inactivated whole-virus vaccine had the greatest protective effect on the rainbow trout after challenge by an intraperitoneal injection of live IHNV, with an RPS rate of 91.67%, which was significantly higher compared with the BEI (83.33%) and formaldehyde (79.17%) groups. These results indicate that the BPL-inactivated IHNV oil-adjuvant vaccine was more effective than the formaldehyde- or BEI-inactivated vaccines. The results of this study provide an important foundation for further studies on inactivated IHNV vaccines.

Inactivation of the Hutchinson strain of hepatitis non-A, non-B virus in intravenous immunoglobulin by beta-propiolactone.

beta-propiolactone (beta-PL) treatment has been evaluated for its ability to inactivate 10(3.5) chimpanzee infectious doses (CID50) of the Hutchinson strain of hepatitis non-A, non-B virus (HNANBV). Two chimpanzees were inoculated with a beta-PL-treated immunoglobulin solution to which this dose of the titrated virus had been added prior to beta-PL treatment. beta-PL treatment was performed in accordance with the production procedure used for a licensed intravenous immunoglobulin preparation. Neither animal developed hepatitis. When subsequently challenged with the same spiked immunoglobulin solution that had not been beta-PL treated, both animals developed clear-cut hepatitis non-A, non-B. The results of this experiment demonstrate that beta-PL treatment is effective for the inactivation of hepatitis non-A, non-B virus in intravenous immunoglobulin.

Concentration-dependent mutation by alkylating agents in human lymphoblasts and Salmonella typhimurium: N-methyl-N-nitrosourethane and beta-propiolactone.

The toxic and mutagenic effects of the alkylating agents N-methyl-N-nitrosourethane (MNUT) and beta-propiolactone (BPL) were quantitatively measured in human lymphoblasts and Salmonella typhimurium. Forward mutation to 6-thioguanine resistance was measured in the human lymphoblasts, and forward mutation to 8-azaguanine resistance was measured in the bacterial cells after equigenerational (1.5 doubling times) exposures. In both systems, the induced mutant fraction rose linearly as a function of concentration for BPL and was biphasic for MNUT. The responses of the two assay systems to eight alkylating agents were compared. The exposure of the cells to each alkylating agent was calculated as exposure concentration multiplied by the time of exposure, and allowance was made for the decomposition of the alkylating agents during exposure (integral exposure). Human cells were 2.5--13 times more sensitive than was S. typhimurium to the alkylating agents methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, N-methyl-N'-nitro-N-nitrosoguanidine, methylnitrosourea, and MNUT. S. typhimurium cells were three times more sensitive to butyl methanesulfonate and 25 times more sensitive to BPL than were human cells.

Antioxidants reduce the mutagenic effect of malonaldehyde and beta-propiolactone. Part IX. Antioxidants and cancer.

Increasing concentrations of malonaldehyde and beta-propiolactone were increasingly mutagenic with 7 mutants of Salmonella typhimurium, 5 of which mutated bya frameshift mechanism and 2 of which mutated through base-pair substitution. The antioxidants vitamin C, vitamin E, selenium and butylated hydroxytoluene (BHT) at 3 logarithmic concentrations markedly reduced mutagenesis in those strains which mutated by frameshift mechanism.

Induction of sex-linked recessive lethals and autosomal translocations by beta-propiolactone in Drosophila: influence of the route of administration on mutagenic activity.

Beta-propiolactone (BPL) was tested for the induction of sex-linked recessive lethals and autosomal translocations in Drosophila melanogaster. The compound was administered to adult males either by oral application or by abdominal injection. When injected, BPL was a potent inducer of sex-linked recessive lethals. When BPL was given by feeding, its mutagenic activity was detectable only when the flies were starved and when the BPL-containing solutions were renewed several times. Nevertheless, the recessive-lethal frequency was one order of magnitude higher with injection. This difference in effects is attributed to (1) rapid decomposition of the compound in aqueous feeding solutions, and to (2) rapid degradation in vivo which restricts the activity of BPL mainly to the site of application. These data are compared with other studies in which both routes of application were applied. BPL induced translocations in stored spermatozoa when injected, but not when fed. This finding seems a logical consequence of (1) the difference in effectiveness of the two routes of application for BPL, and (2) the existence of different LECs for mutation induction (recessive lethals) and for chromosome breakage (translocations). In Drosophila, the breakage capacity of BPL was one order of magnitude lower than that of MMS, when a comparison was made on the basis of equal recessive-lethal frequencies.

XC cell fusion by murine leukemia viruses: fusion from without.

Concentrated murine leukemia virus (MuLV) or MuLV producing cells induce XC cell fusion within an hour leading to syncytia formation. While MuLV inactivated by UV irradiation, beta-propiolactone or hydroxylamine treatment still caused cell fusion, Bromelin- or trypsin treated MuLV was no longer able to fuse XC cells. Though sonicated MuLV induced no XC cell fusion, it interfered with cell fusion as caused by untreated MuLV. XC cells infected by diluted MuLV of a titer lower than 1 X 10(5) PFU/ml formed no syncytia although they produced MuLV. The cell fusion mechanism is discussed.