Attenuation of Vaccinia Virus

Since 1980, in the post-smallpox vaccination era the human population has become increasingly susceptible compared to a generation ago to not only the variola (smallpox) virus, but also other zoonotic orthopoxviruses. The need for safer vaccines against orthopoxviruses is even greater now. The Lister vaccine strain (LIVP) of vaccinia virus was used as a parental virus for generating a recombinant 1421ABJCN clone defective in five virulence genes encoding hemagglutinin (A56R), the IFN--binding protein (B8R), thymidine kinase (J2R), the complement-binding protein (C3L), and the Bcl-2-like inhibitor of apoptosis (N1L). We found that disruption of these loci does not affect replication in mammalian cell cultures. The isogenic recombinant strain 1421ABJCN exhibits a reduced inflammatory response and attenuated neurovirulence relative to LIVP. Virus titers of 1421ABJCN were 3 lg lower versus the parent VACV LIVP when administered by the intracerebral route in new-born mice. In a subcutaneous mouse model, 1421ABJCN displayed levels of VACV-neutralizing antibodies comparable to those of LIVP and conferred protective immunity against lethal challenge by the ectromelia virus. The VACV mutant holds promise as a safe live vaccine strain for preventing smallpox and other orthopoxvirus infections.

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Persisting Humoral Antiviral Immunity within the Japanese Population after the Discontinuation in 1976 of Routine Smallpox Vaccinations

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.12.4.520-524.2005 ◽

2005 ◽

Vol 12 (4) ◽

pp. 520-524 ◽

Cited By ~ 16

Author(s):

Shuji Hatakeyama ◽

Kyoji Moriya ◽

Masayuki Saijo ◽

Yuji Morisawa ◽

Ichiro Kurane ◽

...

Keyword(s):

Vaccinia Virus ◽

Japanese Population ◽

Neutralizing Antibodies ◽

Antiviral Immunity ◽

Smallpox Vaccination ◽

Considerable Proportion ◽

Enzyme Linked Immunosorbent Assay ◽

Specific Immunoglobulin ◽

Specific Igg ◽

Induced Immunity

ABSTRACT Concerns have arisen recently about the possible use of smallpox for a bioterrorism attack. Routine smallpox vaccination was discontinued in Japan in 1976; however, it is uncertain exactly how long vaccination-induced immunity lasts. We sought to evaluate the seroprevalence and intensity of anti-smallpox immunity among representatives of the present Japanese population. The subjects included 876 individuals who were born between 1937 and 1982. Vaccinia virus-specific immunoglobulin G (IgG) levels were measured by enzyme-linked immunosorbent assay (ELISA), and 152 of 876 samples were also tested for the presence of neutralizing antibodies. Of the subjects who were born before 1962, between 1962 and 1968, and between 1969 and 1975, 98.6, 98.6, and 66.0%, respectively, still retained the vaccinia virus-specific IgG with ELISA values for optical density at 405 nm (OD405) of ≥0.10. The corresponding figures for retained IgGs with OD405 values of ≥0.30 were 91.0, 90.3, and 58.2%, respectively. Neutralizing antibodies were also maintained. The sera with OD405 values of ≥0.30 showed 89% sensitivity and a 93% positive predictive value for detection of neutralizing antibodies (≥4). Thus, approximately 80% of persons born before 1969 and 50% of those born between 1969 and 1975 were also found to have maintained neutralizing antibodies against smallpox. A considerable proportion of the previous vaccinated individuals still retain significant levels of antiviral immunity. This long-lasting immunity may provide some protective benefits in the case of reemergence of smallpox, and the disease may not spread as widely and fatally as generally expected.

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ROUTE-COUPLED PATHOGENICITY AND IMMUNOGENICITY OF VACCINIA VIRUS VARIANT INOCULATED MICE

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-pai-1375 ◽

2019 ◽

Author(s):

S. Shchelkunov ◽

A. Sergeev ◽

A. Kabanov ◽

S. Yakubitskyi ◽

T. Bauer ◽

...

Keyword(s):

Vaccinia Virus ◽

Virus Strain ◽

Dna Sequences ◽

Virulence Genes ◽

Clinical Manifestations ◽

World Health ◽

Smallpox Vaccination ◽

Natural Evolution ◽

Vaccinia Virus Strain ◽

Virus Strains

Vaccinia virus had played a key role in the global smallpox eradication. However, in case of mass vaccination with various vaccinia virus strains severe side effects were revealed sometimes ending up with lethal outcomes, especially in immunocompromised humans. Hence, the World Health Organization recommended to cancel smallpox vaccination after declaring in 1980 about smallpox eradication. Over last 40 years, human population virtually lost immunity not only against smallpox, but also against other zoonotic orthopoxvirus infections, such as monkeypox, cowpox, buffalopox, and camel pox. All of them pose an represent increasing threat to human health and heighten a risk of emerging highly contagious viruses due to natural evolution of previous zoonotic orthopoxviruses. In order to prevent development of small outbreaks into spreading epidemics and, thus, to decrease a risk of emergence due to natural evolution of highly pathogenic for humans orthopoxviruses, efforts should be applied to develop safe new generation live vaccines based on vaccinia virus with target virulence genes inactivation. These strains should be examined in laboratory animal models inoculated via different routes. Currently, vaccinia virus often becomes attenuated to create live recombinant vaccines due to inserting target DNA sequences into the virus virulence genes resulting in their inactivation. Vaccinia virus strain LIVP used in the Russian Federation as smallpox vaccine as well as derivative attenuated variant LIVP-GFP created by using genetic engineering methods with inactivating its thymidine kinase gene were examined.Such viruses were intracerebrally inoculated into suckling mice at doses of 101 or 102 PFU/animal for neurovirulence assessment. Adult mice were infected intranasally, subcutaneously or intradermally at doses of 107 or 108 PFU/animal and clinical manifestations were analyzed for 14 days. On 28 day after the onset, blood serum samples were collected from individual mice to measure virus specific antibody level by using ELISA. It was shown that recombinant vaccinia virus strain LIVP-GFP displayed markedly lowered neurovirulence and pathogenicity for mice as compared to parental LIVP. Finally, intradermal route turned out to demonstrate the most safe and effective profile for immunization with both examined vaccinia virus strains.

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Vaccinia Virus H3L Envelope Protein Is a Major Target of Neutralizing Antibodies in Humans and Elicits Protection against Lethal Challenge in Mice

Journal of Virology ◽

10.1128/jvi.79.18.11724-11733.2005 ◽

2005 ◽

Vol 79 (18) ◽

pp. 11724-11733 ◽

Cited By ~ 138

Author(s):

D. Huw Davies ◽

Megan M. McCausland ◽

Conrad Valdez ◽

Devan Huynh ◽

Jenny E. Hernandez ◽

...

Keyword(s):

Antibody Response ◽

Vaccinia Virus ◽

Virus Strain ◽

Envelope Protein ◽

Neutralizing Antibodies ◽

High Titer ◽

Lethal Challenge ◽

Vaccinia Virus Strain ◽

Major Target

ABSTRACT The smallpox vaccine is the prototypic vaccine, yet the viral targets critical for vaccine-mediated protection remain unclear in humans. We have produced protein microarrays of a near-complete vaccinia proteome and used them to determine the major antigen specificities of the human humoral immune response to the smallpox vaccine (Dryvax). H3L, an intracellular mature virion envelope protein, was consistently recognized by high-titer antibodies in the majority of human donors, particularly after secondary immunization. We then focused on examining H3L as a valuable human antibody target. Purified human anti-H3L antibodies exhibited substantial vaccinia virus-neutralizing activity in vitro (50% plaque reduction neutralization test [PRNT50] = 44 μg/ml). Mice also make an immunodominant antibody response to H3L after vaccination with vaccinia virus, as determined by vaccinia virus protein microarray. Mice were immunized with recombinant H3L protein to examine H3L-specific antibody responses in greater detail. H3L-immunized mice developed high-titer vaccinia virus-neutralizing antibodies (mean PRNT50 = 1:3,760). Importantly, H3L-immunized mice were subsequently protected against lethal intranasal challenges with 1 or 5 50% lethal doses (LD50) of pathogenic vaccinia virus strain WR, demonstrating the in vivo value of an anti-H3L response. To formally demonstrate that neutralizing anti-H3L antibodies are protective in vivo, we performed anti-H3L serum passive-transfer experiments. Mice receiving H3L-neutralizing antiserum were protected from a lethal challenge with 3 LD50 of vaccinia virus strain WR (5/10 versus 0/10; P < 0.02). Together, these data show that H3L is a major target of the human anti-poxvirus antibody response and is likely to be a key contributor to protection against poxvirus infection and disease.

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Differential Antigen Requirements for Protection against Systemic and Intranasal Vaccinia Virus Challenges in Mice

Journal of Virology ◽

10.1128/jvi.00353-08 ◽

2008 ◽

Vol 82 (14) ◽

pp. 6829-6837 ◽

Cited By ~ 24

Author(s):

David R. Kaufman ◽

Jaap Goudsmit ◽

Lennart Holterman ◽

Bonnie A. Ewald ◽

Matthew Denholtz ◽

...

Keyword(s):

Vaccinia Virus ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Recombinant Adenovirus ◽

Protective Efficacy ◽

Postexposure Prophylaxis ◽

Virus Challenge ◽

Protective Antigens ◽

A Subunit ◽

Potential Strategy

ABSTRACT The development of a subunit vaccine for smallpox represents a potential strategy to avoid the safety concerns associated with replication-competent vaccinia virus. Preclinical studies to date with subunit smallpox vaccine candidates, however, have been limited by incomplete information regarding protective antigens and the requirement for multiple boost immunizations to afford protective immunity. Here we explore the protective efficacy of replication-incompetent, recombinant adenovirus serotype 35 (rAd35) vectors expressing the vaccinia virus intracellular mature virion (IMV) antigens A27L and L1R and extracellular enveloped virion (EEV) antigens A33R and B5R in a murine vaccinia virus challenge model. A single immunization with the rAd35-L1R vector effectively protected mice against a lethal systemic vaccinia virus challenge. The rAd35-L1R vector also proved more efficacious than the combination of four rAd35 vectors expressing A27L, L1R, A33R, and B5R. Moreover, serum containing L1R-specific neutralizing antibodies afforded postexposure prophylaxis after systemic vaccinia virus infection. In contrast, the combination of rAd35-L1R and rAd35-B5R vectors was required to protect mice against a lethal intranasal vaccinia virus challenge, suggesting that both IMV- and EEV-specific immune responses are important following intranasal infection. Taken together, these data demonstrate that different protective antigens are required based on the route of vaccinia virus challenge. These studies also suggest that rAd vectors warrant further assessment as candidate subunit smallpox vaccines.

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Vaccinia virus-based vaccines confer protective immunity against SARS-CoV-2 virus in Syrian hamsters

10.1101/2021.08.03.454910 ◽

2021 ◽

Author(s):

Rakesh Kulkarni ◽

Wen-Ching Chen ◽

Ying Lee ◽

Chi-Fei Kao ◽

Shiu-Lok Hu ◽

...

Keyword(s):

Vaccinia Virus ◽

Mammalian Cells ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Respiratory Illness ◽

Cold Chain ◽

Infection Model ◽

Recombinant Vaccines ◽

Viral Spread ◽

Severe Respiratory Illness

COVID-19 in humans is caused by Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that belongs to the beta family of coronaviruses. SARS-CoV-2 causes severe respiratory illness in 10-15% of infected individuals and mortality in 2-3%. Vaccines are urgently needed to prevent infection and to contain viral spread. Although several mRNA- and adenovirus-based vaccines are highly effective, their dependence on the cold chain transportation makes global vaccination a difficult task. In this context, a stable lyophilized vaccine may present certain advantages. Accordingly, establishing additional vaccine platforms remains vital to tackle SARS-CoV-2 and any future variants that may arise. Vaccinia virus (VACV) has been used to eradicate smallpox disease, and several attenuated viral strains with enhanced safety for human applications have been developed. We have generated two candidate SARS-CoV-2 vaccines based on two vaccinia viral strains, MVA and v-NY, that express full-length SARS-CoV-2 spike protein. Whereas MVA is growth-restricted in mammalian cells, the v-NY strain is replication-competent. We demonstrate that both candidate recombinant vaccines induce high titers of neutralizing antibodies in C57BL/6 mice vaccinated according to prime-boost regimens. Furthermore, our vaccination regimens generated TH1-biased immune responses in mice. Most importantly, prime-boost vaccination of a Syrian hamster infection model with MVA-S and v-NY-S protected the hamsters against SARS-CoV-2 infection, supporting that these two vaccines are promising candidates for future development. Finally, our vaccination regimens generated neutralizing antibodies that partially cross-neutralized SARS-CoV-2 variants of concern.

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Homologous and heterologous glycoproteins induce protection against Junin virus challenge in guinea pigs

Microbiology ◽

10.1099/0022-1317-81-5-1273 ◽

2000 ◽

Vol 81 (5) ◽

pp. 1273-1281 ◽

Cited By ~ 17

Author(s):

Nora López ◽

Luis Scolaro ◽

Carlos Rossi ◽

Rodrigo Jácamo ◽

Nélida Candurra ◽

...

Keyword(s):

Vaccinia Virus ◽

Guinea Pigs ◽

Neutralizing Antibodies ◽

Recombinant Vaccinia Virus ◽

Glycoprotein Precursor ◽

Lethal Challenge ◽

Recombinant Vaccinia ◽

Junin Virus ◽

Virus Challenge ◽

Junín Virus

Tacaribe virus (TACV) is an arenavirus that is genetically and antigenically closely related to Junin virus (JUNV), the aetiological agent of Argentine haemorrhagic fever (AHF). It is well established that TACV protects experimental animals fully against an otherwise lethal challenge with JUNV. To gain information on the nature of the antigens involved in cross-protection, recombinant vaccinia viruses were constructed that express the glycoprotein precursor (VV–GTac) or the nucleocapsid protein (VV–N) of TACV. TACV proteins expressed by vaccinia virus were indistinguishable from authentic virus proteins by gel electrophoresis. Guinea pigs inoculated with VV–GTac or VV–N elicited antibodies that immunoprecipitated authentic TACV proteins. Antibodies generated by VV–GTac neutralized TACV infectivity. Levels of antibodies after priming and boosting with recombinant vaccinia virus were comparable to those elicited in TACV infection. To evaluate the ability of recombinant vaccinia virus to protect against experimental AHF, guinea pigs were challenged with lethal doses of JUNV. Fifty per cent of the animals immunized with VV–GTac survived, whereas all animals inoculated with VV–N or vaccinia virus died. Having established that the heterologous glycoprotein protects against JUNV challenge, a recombinant vaccinia virus was constructed that expresses JUNV glycoprotein precursor (VV–GJun). The size and reactivity to monoclonal antibodies of the vaccinia virus-expressed and authentic JUNV glycoproteins were indistinguishable. Seventy-two per cent of the animals inoculated with two doses of VV–GJun survived lethal JUNV challenge. Protection with either VV–GJun or VV–GTac occurred in the presence of low or undetectable levels of neutralizing antibodies to JUNV.

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Search for Correlates of Protective Immunity Conferred by Anthrax Vaccine

Infection and Immunity ◽

10.1128/iai.69.5.2888-2893.2001 ◽

2001 ◽

Vol 69 (5) ◽

pp. 2888-2893 ◽

Cited By ~ 175

Author(s):

Shaul Reuveny ◽

Moshe D. White ◽

Yaakov Y. Adar ◽

Yaron Kafri ◽

Zeev Altboum ◽

...

Keyword(s):

Antibody Titer ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Protective Antigen ◽

Surrogate Marker ◽

Neutralizing Antibody ◽

Enzyme Linked Immunosorbent Assay ◽

Lethal Challenge ◽

Anthrax Spores ◽

Antibody Titers

ABSTRACT Vaccination by anthrax protective antigen (PA)-based vaccines requires multiple immunization, underlying the need to develop more efficacious vaccines or alternative vaccination regimens. In spite of the vast use of PA-based vaccines, the definition of a marker for protective immunity is still lacking. Here we describe studies designed to help define such markers. To this end we have immunized guinea pigs by different methods and monitored the immune response and the corresponding extent of protection against a lethal challenge with anthrax spores. Active immunization was performed by a single injection using one of two methods: (i) vaccination with decreasing amounts of PA and (ii) vaccination with constant amounts of PA that had been thermally inactivated for increasing periods. In both studies a direct correlation between survival and neutralizing-antibody titer was found (r 2 = 0.92 and 0.95, respectively). Most significantly, in the two protocols a similar neutralizing-antibody titer range provided 50% protection. Furthermore, in a complementary study involving passive transfer of PA hyperimmune sera to naive animals, a similar correlation between neutralizing-antibody titers and protection was found. In all three immunization studies, neutralization titers of at least 300 were sufficient to confer protection against a dose of 40 50% lethal doses (LD50) of virulent anthrax spores of the Vollum strain. Such consistency in the correlation of protective immunity with anti-PA antibody titers was not observed for antibody titers determined by an enzyme-linked immunosorbent assay. Taken together, these results clearly demonstrate that neutralizing antibodies to PA constitute a major component of the protective immunity against anthrax and suggest that this parameter could be used as a surrogate marker for protection.

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Vaccination and Protection of Pigs against Pleuropneumonia with a Vaccine Strain of Actinobacillus pleuropneumoniaeProduced by Site-Specific Mutagenesis of the ApxII Operon

Infection and Immunity ◽

10.1128/iai.67.4.1962-1966.1999 ◽

1999 ◽

Vol 67 (4) ◽

pp. 1962-1966 ◽

Cited By ~ 29

Author(s):

C. T. Prideaux ◽

C. Lenghaus ◽

J. Krywult ◽

A. L. M. Hodgson

Keyword(s):

Mutant Strain ◽

Vaccine Strain ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Actinobacillus Pleuropneumoniae ◽

Intranasal Route ◽

Gene Encoding ◽

Site Specific ◽

Porcine Pleuropneumonia

ABSTRACT The production of toxin (Apx)-neutralizing antibodies during infection plays a major role in the induction of protective immunity toActinobacillus pleuropneumoniae reinfection. In the present study, the gene encoding the ApxII-activating protein,apxIIC, was insertionally inactivated on the chromosome of a serovar 7 strain, HS93. Expression of the structural toxin, ApxIIA, and of the two genes required for its secretion, apxIB andapxID, still occurs in this strain. The resulting mutant strain, HS93C− Ampr, was found to secrete the unactivated toxin. Pigs vaccinated with live HS93C−Ampr via the intranasal route were protected against a cross-serovar challenge with a virulent serovar 1 strain ofA. pleuropneumoniae. This is the first reported vaccine strain of A. pleuropneumoniae which can be delivered live to pigs and offers cross-serovar protection against porcine pleuropneumonia.

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Protective Immunity in Macaques Vaccinated with a Modified Vaccinia Virus Ankara-Based Measles Virus Vaccine in the Presence of Passively Acquired Antibodies

Journal of Virology ◽

10.1128/jvi.74.9.4236-4243.2000 ◽

2000 ◽

Vol 74 (9) ◽

pp. 4236-4243 ◽

Cited By ~ 91

Author(s):

Koert J. Stittelaar ◽

Linda S. Wyatt ◽

Rik L. de Swart ◽

Helma W. Vos ◽

Jan Groen ◽

...

Keyword(s):

Vaccinia Virus ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Measles Virus ◽

Wild Type ◽

Live Attenuated Vaccine ◽

Cell Responses ◽

Modified Vaccinia Virus Ankara ◽

Current Vaccine ◽

Induced Immunity

ABSTRACT Recombinant modified vaccinia virus Ankara (MVA), encoding the measles virus (MV) fusion (F) and hemagglutinin (H) (MVA-FH) glycoproteins, was evaluated in an MV vaccination-challenge model with macaques. Animals were vaccinated twice in the absence or presence of passively transferred MV-neutralizing macaque antibodies and challenged 1 year later intratracheally with wild-type MV. After the second vaccination with MVA-FH, all the animals developed MV-neutralizing antibodies and MV-specific T-cell responses. Although MVA-FH was slightly less effective in inducing MV-neutralizing antibodies in the absence of passively transferred antibodies than the currently used live attenuated vaccine, it proved to be more effective in the presence of such antibodies. All vaccinated animals were effectively protected from the challenge infection. These data suggest that MVA-FH should be further tested as an alternative to the current vaccine for infants with maternally acquired MV-neutralizing antibodies and for adults with waning vaccine-induced immunity.

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Cross-reactivity reduced dengue virus 2 vaccine has no cross-protection against heterotypic dengue viruses

Future Virology ◽

10.2217/fvl-2019-0115 ◽

2020 ◽

Vol 15 (2) ◽

pp. 79-90

Author(s):

Jedhan U Galula ◽

Chung-Yu Yang ◽

Brent S Davis ◽

Gwong-Jen J Chang ◽

Day-Yu Chao

Keyword(s):

Survival Rate ◽

Dengue Virus ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Protective Efficacy ◽

Cross Reactivity ◽

Lethal Challenge ◽

Denv Serotypes ◽

Female Mice ◽

Virus Like Particle

Aim: This study assessed how prime-boost strategies influence the immunogenicity of a cross-reactivity reduced dengue virus 2 vaccine (DENV-2 RD). Materials & methods: Mice were immunized with DENV-2 RD vaccines in a heterologous DNA and virus-like particle (VLP) prime-boost. Elicited antibodies were analyzed for neutralization and protective efficacy against four DENV serotypes. Results: DENV-2 RD DNA-VLP had induced higher and broader levels of total IgG and neutralizing antibodies with statistically significant IgG titers against DENV-2 and -3. Only pups of DENV-2 RD DNA-VLP immunized female mice were fully protected against homotypic DENV challenge and partially protected (60% survival rate) against heterotypic DENV-3 lethal challenge. Conclusion: DENV-2 RD vaccine requires a multivalent format to effectively elicit a balanced and protective immunity across all four DENV serotypes.

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