Limits...
Simian varicella virus infection of rhesus macaques recapitulates essential features of varicella zoster virus infection in humans.

Messaoudi I, Barron A, Wellish M, Engelmann F, Legasse A, Planer S, Gilden D, Nikolich-Zugich J, Mahalingam R - PLoS Pathog. (2009)

Bottom Line: Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection.More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted.Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation.

View Article: PubMed Central - PubMed

Affiliation: Vaccine and Gene Therapy, Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, Oregon, United States of America. messaoud@ohsu.edu

ABSTRACT
Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation.

Show MeSH

Related in: MedlinePlus

SVV infection of rhesus macaques elicits a B cell response after the appearance of varicella rash.B cells were separated into three subsets based on expression of IgD and CD27: CD27−IgD+; CD27+IgD+; and isotype-switched CD27+IgD− cells. A representative profile from PBMCs obtained from monkey 24953 on day 0 (A, left) is shown. B cell proliferation within CD27+IgD+ and CD27+IgD− subsets was measured using flow cytometry based on expression of the nuclear protein Ki67, which is up-regulated upon entry into the cell cycle. B cell proliferation was minimal before SVV infection (0 dpi, A, middle), but increased dramatically 14 dpi (A, right). Throughout the course of SVV infection in all 4 monkeys, the number of Ki67+ CD27+IgD+ (panel B) and CD27+IgD− B cells (C) increased dramatically 14 dpi compared to 0 dpi in PBMCs. In BAL of all 4 monkeys, increased numbers of Ki67+ IgD−CD27+ B cells were seen throughout the course of infection compared to 0 dpi (panel D), although no significant proliferation of IgD+CD27+ B cells was detected (data not shown). In all 4 monkeys, SVV-specific IgG antibodies appeared 7 dpi, peaked 18–21 dpi (as detected by ELISA) and remained stable up to 70 dpi (E).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2770849&req=5

ppat-1000657-g003: SVV infection of rhesus macaques elicits a B cell response after the appearance of varicella rash.B cells were separated into three subsets based on expression of IgD and CD27: CD27−IgD+; CD27+IgD+; and isotype-switched CD27+IgD− cells. A representative profile from PBMCs obtained from monkey 24953 on day 0 (A, left) is shown. B cell proliferation within CD27+IgD+ and CD27+IgD− subsets was measured using flow cytometry based on expression of the nuclear protein Ki67, which is up-regulated upon entry into the cell cycle. B cell proliferation was minimal before SVV infection (0 dpi, A, middle), but increased dramatically 14 dpi (A, right). Throughout the course of SVV infection in all 4 monkeys, the number of Ki67+ CD27+IgD+ (panel B) and CD27+IgD− B cells (C) increased dramatically 14 dpi compared to 0 dpi in PBMCs. In BAL of all 4 monkeys, increased numbers of Ki67+ IgD−CD27+ B cells were seen throughout the course of infection compared to 0 dpi (panel D), although no significant proliferation of IgD+CD27+ B cells was detected (data not shown). In all 4 monkeys, SVV-specific IgG antibodies appeared 7 dpi, peaked 18–21 dpi (as detected by ELISA) and remained stable up to 70 dpi (E).

Mentions: To assess the B cell response, we measured the fold increase in the number of Ki67+ isotype-switched B cells. PBMCs and BAL cells were stained with antibodies directed against CD20, IgD and CD27 to distinguish between three subsets: CD27-IgD+ (most likely naïve), CD27+IgD+, and CD27+IgD− (isotype-switched B cells) [33] (Figure 3A, left). Cells were then fixed and the nuclear membrane was permeabilized before staining with anti-Ki67 antibody (Figure 3A, middle and right). SVV infection induced a robust proliferation of CD27+IgD+ as well as isotype-switched CD27+IgD− B cells in PBMCs as indicated by an increase in the frequency of Ki67+ cells on dpi 14 compared to dpi 0 (Figure 3A middle and right panels; Figure 3B and C, respectively). Analysis of BAL samples revealed an increased frequency of proliferating CD27+IgD− B cells, that were detected earlier (7 dpi) than in PBMCs (14 dpi) (Figure 3D). No significant proliferation of CD27+IgD+ B cells was found (data not shown). The SVV-specific IgG titer revealed an IgG response by 12 dpi that peaked18–21 dpi (Figure 3E).


Simian varicella virus infection of rhesus macaques recapitulates essential features of varicella zoster virus infection in humans.

Messaoudi I, Barron A, Wellish M, Engelmann F, Legasse A, Planer S, Gilden D, Nikolich-Zugich J, Mahalingam R - PLoS Pathog. (2009)

SVV infection of rhesus macaques elicits a B cell response after the appearance of varicella rash.B cells were separated into three subsets based on expression of IgD and CD27: CD27−IgD+; CD27+IgD+; and isotype-switched CD27+IgD− cells. A representative profile from PBMCs obtained from monkey 24953 on day 0 (A, left) is shown. B cell proliferation within CD27+IgD+ and CD27+IgD− subsets was measured using flow cytometry based on expression of the nuclear protein Ki67, which is up-regulated upon entry into the cell cycle. B cell proliferation was minimal before SVV infection (0 dpi, A, middle), but increased dramatically 14 dpi (A, right). Throughout the course of SVV infection in all 4 monkeys, the number of Ki67+ CD27+IgD+ (panel B) and CD27+IgD− B cells (C) increased dramatically 14 dpi compared to 0 dpi in PBMCs. In BAL of all 4 monkeys, increased numbers of Ki67+ IgD−CD27+ B cells were seen throughout the course of infection compared to 0 dpi (panel D), although no significant proliferation of IgD+CD27+ B cells was detected (data not shown). In all 4 monkeys, SVV-specific IgG antibodies appeared 7 dpi, peaked 18–21 dpi (as detected by ELISA) and remained stable up to 70 dpi (E).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2770849&req=5

ppat-1000657-g003: SVV infection of rhesus macaques elicits a B cell response after the appearance of varicella rash.B cells were separated into three subsets based on expression of IgD and CD27: CD27−IgD+; CD27+IgD+; and isotype-switched CD27+IgD− cells. A representative profile from PBMCs obtained from monkey 24953 on day 0 (A, left) is shown. B cell proliferation within CD27+IgD+ and CD27+IgD− subsets was measured using flow cytometry based on expression of the nuclear protein Ki67, which is up-regulated upon entry into the cell cycle. B cell proliferation was minimal before SVV infection (0 dpi, A, middle), but increased dramatically 14 dpi (A, right). Throughout the course of SVV infection in all 4 monkeys, the number of Ki67+ CD27+IgD+ (panel B) and CD27+IgD− B cells (C) increased dramatically 14 dpi compared to 0 dpi in PBMCs. In BAL of all 4 monkeys, increased numbers of Ki67+ IgD−CD27+ B cells were seen throughout the course of infection compared to 0 dpi (panel D), although no significant proliferation of IgD+CD27+ B cells was detected (data not shown). In all 4 monkeys, SVV-specific IgG antibodies appeared 7 dpi, peaked 18–21 dpi (as detected by ELISA) and remained stable up to 70 dpi (E).
Mentions: To assess the B cell response, we measured the fold increase in the number of Ki67+ isotype-switched B cells. PBMCs and BAL cells were stained with antibodies directed against CD20, IgD and CD27 to distinguish between three subsets: CD27-IgD+ (most likely naïve), CD27+IgD+, and CD27+IgD− (isotype-switched B cells) [33] (Figure 3A, left). Cells were then fixed and the nuclear membrane was permeabilized before staining with anti-Ki67 antibody (Figure 3A, middle and right). SVV infection induced a robust proliferation of CD27+IgD+ as well as isotype-switched CD27+IgD− B cells in PBMCs as indicated by an increase in the frequency of Ki67+ cells on dpi 14 compared to dpi 0 (Figure 3A middle and right panels; Figure 3B and C, respectively). Analysis of BAL samples revealed an increased frequency of proliferating CD27+IgD− B cells, that were detected earlier (7 dpi) than in PBMCs (14 dpi) (Figure 3D). No significant proliferation of CD27+IgD+ B cells was found (data not shown). The SVV-specific IgG titer revealed an IgG response by 12 dpi that peaked18–21 dpi (Figure 3E).

Bottom Line: Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection.More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted.Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation.

View Article: PubMed Central - PubMed

Affiliation: Vaccine and Gene Therapy, Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, Oregon, United States of America. messaoud@ohsu.edu

ABSTRACT
Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation.

Show MeSH
Related in: MedlinePlus