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Robust intrapulmonary CD8 T cell responses and protection with an attenuated N1L deleted vaccinia virus.

Mathew A, O'Bryan J, Marshall W, Kotwal GJ, Terajima M, Green S, Rothman AL, Ennis FA - PLoS ONE (2008)

Bottom Line: Vaccinia viruses have been used as a model for viral disease and as a protective live vaccine.Infection by the intranasal, intraperitoneal, and tail scarification routes resulted in the robust induction of cytolytic virus-specific CD8 T cells in the spleens and the lungs.These results indicate that the attenuated vGK5 virus protects against subsequent infection and suggest that the N1L protein limits the strength of the early antiviral CD8 T cell response following respiratory infection.

View Article: PubMed Central - PubMed

Affiliation: Center for Infectious Disease and Vaccine Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA. anuja.mathew@umassmed.edu

ABSTRACT

Background: Vaccinia viruses have been used as a model for viral disease and as a protective live vaccine.

Methodology and principal findings: We investigated the immunogenicity of an attenuated strain of vaccinia virus engineered to inactivate the N1L gene (vGK5). Using the intranasal route, this recombinant virus was 2 logs less virulent compared to the wildtype VACV-WR. Infection by the intranasal, intraperitoneal, and tail scarification routes resulted in the robust induction of cytolytic virus-specific CD8 T cells in the spleens and the lungs. VACV-specific antibodies were also detected in the sera of mice infected 3-5 months prior with the attenuated vGK5 virus. Finally, mice immunized with vGK5 were significantly protected when challenged with a lethal dose of VACV-WR.

Conclusions: These results indicate that the attenuated vGK5 virus protects against subsequent infection and suggest that the N1L protein limits the strength of the early antiviral CD8 T cell response following respiratory infection.

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Weight loss curves of individual mice and splenocyte counts following i.n. VACV infection of C57/BL6 mice.(A) Groups of female C57/BL6 mice (n = 5–8) were infected with 105, 106 and 107 PFU of vGK5 by the i.n. route. The percentage of weight relative to the initial body weight (100%) was plotted and the data are presented as percent change in body weight following infection. † depicts days that individual mice were last alive. (B) Average spleen counts±standard deviation of mice were assessed by trypan blue exclusion at days 3, 5 and 7 post infection with 106 VACV-WR and vGK5 by the i.n. route. Data shown are representative of 2 experiments performed and demonstrate that high dose VACV-WR i.n. infections result in significantly (p<0.05) lower lymphocytes in the spleens during acute infection.
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pone-0003323-g001: Weight loss curves of individual mice and splenocyte counts following i.n. VACV infection of C57/BL6 mice.(A) Groups of female C57/BL6 mice (n = 5–8) were infected with 105, 106 and 107 PFU of vGK5 by the i.n. route. The percentage of weight relative to the initial body weight (100%) was plotted and the data are presented as percent change in body weight following infection. † depicts days that individual mice were last alive. (B) Average spleen counts±standard deviation of mice were assessed by trypan blue exclusion at days 3, 5 and 7 post infection with 106 VACV-WR and vGK5 by the i.n. route. Data shown are representative of 2 experiments performed and demonstrate that high dose VACV-WR i.n. infections result in significantly (p<0.05) lower lymphocytes in the spleens during acute infection.

Mentions: We first assessed the pathogenicity of the attenuated N1L deficient vGK5 virus and the wildtype VACV-WR after intranasal infection as this route of infection with VACV simulates smallpox infection in humans. In agreement with published data [6], [21]–[23], the LD50 for VACV-WR in C57/BL6 mice was 4.2×104 PFU. Mice were next monitored for weight loss and survival after infection with varying doses of the recombinant attenuated virus, vGK5 virus (Fig. 1A). Lines represent weight curves of individual mice. The LD50 in age matched C57/BL6 mice was 4.2×106 PFU based on the Reed and Muench method [24]. We determined the absolute numbers of lymphocytes recruited into the spleens of mice infected with 106 PFU VACV-WR and vGK5 by the intranasal route. We detected a significant decrease in the total number of splenocytes in mice that were administered VACV-WR. By day 7, these mice were moribund (Fig. 1B). In contrast, when mice were administered 106 PFU of the attenuated vGK5 virus by the i.n. route, there was an increase in the total number of lymphocytes in the spleens of infected mice with greater than 50% of the CD8 T cells expressing high levels of the activation marker CD11a (data not shown).


Robust intrapulmonary CD8 T cell responses and protection with an attenuated N1L deleted vaccinia virus.

Mathew A, O'Bryan J, Marshall W, Kotwal GJ, Terajima M, Green S, Rothman AL, Ennis FA - PLoS ONE (2008)

Weight loss curves of individual mice and splenocyte counts following i.n. VACV infection of C57/BL6 mice.(A) Groups of female C57/BL6 mice (n = 5–8) were infected with 105, 106 and 107 PFU of vGK5 by the i.n. route. The percentage of weight relative to the initial body weight (100%) was plotted and the data are presented as percent change in body weight following infection. † depicts days that individual mice were last alive. (B) Average spleen counts±standard deviation of mice were assessed by trypan blue exclusion at days 3, 5 and 7 post infection with 106 VACV-WR and vGK5 by the i.n. route. Data shown are representative of 2 experiments performed and demonstrate that high dose VACV-WR i.n. infections result in significantly (p<0.05) lower lymphocytes in the spleens during acute infection.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2553181&req=5

pone-0003323-g001: Weight loss curves of individual mice and splenocyte counts following i.n. VACV infection of C57/BL6 mice.(A) Groups of female C57/BL6 mice (n = 5–8) were infected with 105, 106 and 107 PFU of vGK5 by the i.n. route. The percentage of weight relative to the initial body weight (100%) was plotted and the data are presented as percent change in body weight following infection. † depicts days that individual mice were last alive. (B) Average spleen counts±standard deviation of mice were assessed by trypan blue exclusion at days 3, 5 and 7 post infection with 106 VACV-WR and vGK5 by the i.n. route. Data shown are representative of 2 experiments performed and demonstrate that high dose VACV-WR i.n. infections result in significantly (p<0.05) lower lymphocytes in the spleens during acute infection.
Mentions: We first assessed the pathogenicity of the attenuated N1L deficient vGK5 virus and the wildtype VACV-WR after intranasal infection as this route of infection with VACV simulates smallpox infection in humans. In agreement with published data [6], [21]–[23], the LD50 for VACV-WR in C57/BL6 mice was 4.2×104 PFU. Mice were next monitored for weight loss and survival after infection with varying doses of the recombinant attenuated virus, vGK5 virus (Fig. 1A). Lines represent weight curves of individual mice. The LD50 in age matched C57/BL6 mice was 4.2×106 PFU based on the Reed and Muench method [24]. We determined the absolute numbers of lymphocytes recruited into the spleens of mice infected with 106 PFU VACV-WR and vGK5 by the intranasal route. We detected a significant decrease in the total number of splenocytes in mice that were administered VACV-WR. By day 7, these mice were moribund (Fig. 1B). In contrast, when mice were administered 106 PFU of the attenuated vGK5 virus by the i.n. route, there was an increase in the total number of lymphocytes in the spleens of infected mice with greater than 50% of the CD8 T cells expressing high levels of the activation marker CD11a (data not shown).

Bottom Line: Vaccinia viruses have been used as a model for viral disease and as a protective live vaccine.Infection by the intranasal, intraperitoneal, and tail scarification routes resulted in the robust induction of cytolytic virus-specific CD8 T cells in the spleens and the lungs.These results indicate that the attenuated vGK5 virus protects against subsequent infection and suggest that the N1L protein limits the strength of the early antiviral CD8 T cell response following respiratory infection.

View Article: PubMed Central - PubMed

Affiliation: Center for Infectious Disease and Vaccine Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA. anuja.mathew@umassmed.edu

ABSTRACT

Background: Vaccinia viruses have been used as a model for viral disease and as a protective live vaccine.

Methodology and principal findings: We investigated the immunogenicity of an attenuated strain of vaccinia virus engineered to inactivate the N1L gene (vGK5). Using the intranasal route, this recombinant virus was 2 logs less virulent compared to the wildtype VACV-WR. Infection by the intranasal, intraperitoneal, and tail scarification routes resulted in the robust induction of cytolytic virus-specific CD8 T cells in the spleens and the lungs. VACV-specific antibodies were also detected in the sera of mice infected 3-5 months prior with the attenuated vGK5 virus. Finally, mice immunized with vGK5 were significantly protected when challenged with a lethal dose of VACV-WR.

Conclusions: These results indicate that the attenuated vGK5 virus protects against subsequent infection and suggest that the N1L protein limits the strength of the early antiviral CD8 T cell response following respiratory infection.

Show MeSH
Related in: MedlinePlus