scholarly journals CD80 and CD86 Control Antiviral CD8+ T-Cell Function and Immune Surveillance of Murine Gammaherpesvirus 68

2006 ◽  
Vol 80 (18) ◽  
pp. 9159-9170 ◽  
Author(s):  
Shinichiro Fuse ◽  
Joshua J. Obar ◽  
Sarah Bellfy ◽  
Erica K. Leung ◽  
Weijun Zhang ◽  
...  

ABSTRACT The interactions between CD80 and CD86 on antigen-presenting cells and CD28 on T cells serve as an important costimulatory signal in the activation of T cells. Although the simplistic two-signal hypothesis has been challenged in recent years by the identification of different costimulators, this classical pathway has been shown to significantly impact antiviral humoral and cellular immune responses. How the CD80/CD86-CD28 pathway affects the control of chronic or latent infections has been less well characterized. In this study, we investigated its role in antiviral immune responses against murine gammaherpesvirus 68 (MHV-68) and immune surveillance using CD80/CD86−/− mice. In the absence of CD80/CD86, primary antiviral CD8+ T-cell responses and the induction of neutralizing antibodies were severely impaired. During long-term immune surveillance, the virus-specific CD8+ T cells were impaired in IFN-γ production and secondary expansion and exhibited an altered phenotype. Surprisingly, a low level of viral reactivation in the lung was observed, and this effect was independent of CD28 and CTLA-4. Thus, CD80 and CD86, signaling through CD28 and possibly another unidentified receptor, are required for optimal immune surveillance and antiviral immune responses to murine gammaherpesvirus.

2008 ◽  
Vol 82 (22) ◽  
pp. 11016-11022 ◽  
Author(s):  
Francesca Giannoni ◽  
Ashley Shea ◽  
Chandra Inglis ◽  
Lian Ni Lee ◽  
Sally R. Sarawar

ABSTRACT CD4 T cells are not essential for primary clearance of replicating murine gammaherpesvirus 68 (MHV-68) but are required for effective long-term control. The virus reactivates in the lungs of major histocompatibility complex class II-deficient (CII−/−) mice that lack functional CD4 T cells. CD40 ligand (CD40L) is upregulated on activated CD4 T cells, and it is thought that CD40-CD40L interactions are an important component of CD4 T-cell help. Our previous studies have shown that agonistic antibodies to CD40 can substitute for CD4 T-cell function in the long-term control of MHV-68. In the present study, we sought to identify the CD40-positive cell type mediating this effect. To address this question, we adoptively transferred MHV-68 peptide-pulsed CII−/− dendritic cells (DC) that had been treated with an agonistic antibody to CD40 into MHV-68-infected CII−/− recipients. Viral reactivation was significantly lower in mice injected with anti-CD40-treated DC than in those injected with control DC or in mice that did not receive any DC. However, in similar experiments with B cells, anti-CD40 treatment had no effect. We also investigated the requirement for CD40 expression on T cells by adoptive transfer of T cells from CD40+/+ or CD40−/− mice into T-cell-deficient recipients that were subsequently infected with MHV-68. The results showed that CD40 expression on T cells is not necessary for preventing viral reactivation. Taken together, our data suggest that CD40 engagement on DC, but not on T or B cells, is essential for effective long-term control of MHV-68.


2008 ◽  
Vol 82 (24) ◽  
pp. 12205-12212 ◽  
Author(s):  
Sara Gredmark-Russ ◽  
Evelyn J. Cheung ◽  
Marisa K. Isaacson ◽  
Hidde L. Ploegh ◽  
Gijsbert M. Grotenbreg

ABSTRACT Infection of mice with murine gammaherpesvirus 68 (MHV-68) robustly activates CD8 T cells, but only six class I major histocompatibility complex (MHC)-restricted epitopes have been described to date for the widely used H-2 b haplotype mice. To explore the specificity and kinetics of the cytotoxic T-lymphocyte response in MHV-68-infected C57BL/6 mice, we screened for H-2Kb- and H-2Db-restricted epitopes using a set of 384 candidate epitopes in an MHC tetramer-based approach and identified 19 new epitopes in 16 different open reading frames. Of the six known H-2Kb- and H-2Db-restricted epitopes, we confirmed a response against three and did not detect CD8 T-cell-specific responses for the remaining three. The peak of the CD8 T-cell response to most peptides occurs between 6 and 10 days postinfection. The respective MHC tetramer-positive CD8 T cells display an activated/effector phenotype (CD62Llo and CD44hi) and produce gamma interferon upon peptide stimulation ex vivo. MHV-68 infection in vivo elicits a response to multiple viral epitopes, derived from both early and late viral antigens, illustrating a far broader T-cell repertoire and more-rapid activation than those previously recorded.


2001 ◽  
Vol 75 (9) ◽  
pp. 4435-4438 ◽  
Author(s):  
Gabrielle T. Belz ◽  
Peter C. Doherty

ABSTRACT The cycling characteristics of CD8+ T cells specific for two lytic-phase epitopes of murine gammaherpesvirus 68 (γHV68) have been analyzed for mice with high or low levels of virus persistence. The extent of cell division is generally reflective of the antigen load and suggests that γHV68 may be regularly reactivating from latency for some months after the resolution of the acute phase of the infectious process. Although γHV68 infection is also associated with massive proliferation of lymphocytes that are not obviously specific for the virus, the level of “bystander-induced” cycling in a population of influenza virus-specific CD8+ T cells was generally fourfold lower than the extent of cell division seen for the antigen-driven, γHV68-specific response. The overall conclusion is that turnover rates substantially in excess of 5 to 10% over 6 days for CD8+ “memory” T-cell populations are likely to be reflective of continued antigenic exposure.


2004 ◽  
Vol 78 (13) ◽  
pp. 6836-6845 ◽  
Author(s):  
James Scott McClellan ◽  
Scott A. Tibbetts ◽  
Shivaprakash Gangappa ◽  
Kelly A. Brett ◽  
Herbert W. Virgin

ABSTRACT We have previously demonstrated that it is possible to effectively vaccinate against long-term murine gammaherpesvirus 68 (γHV68) latency by using a reactivation-deficient virus as a vaccine (S. A. Tibbetts, J. S. McClellan, S. Gangappa, S. H. Speck, and H. W. Virgin IV, J. Virol. 77:2522-2529, 2003). Immune antibody was capable of recapitulating aspects of this vaccination. This led us to determine whether antibody is required for vaccination against latency. Using mice lacking antigen-specific antibody responses, we demonstrate here that antibody and B cells are not required for vaccination against latency. We also show that surveillance of latent infection in normal animals depends on CD4 and CD8 T cells, suggesting that T cells might be capable of preventing the establishment of latency. In the absence of an antibody response, CD4 T cells but not CD8 T cells are required for effective vaccination against latency in peritoneal cells, while either CD4 or CD8 T cells can prevent the establishment of splenic latency. Therefore, CD4 T cells play a critical role in immune surveillance of gammaherpesvirus latency and can mediate vaccination against latency in the absence of antibody responses.


2010 ◽  
Vol 84 (6) ◽  
pp. 2881-2892 ◽  
Author(s):  
Michael L. Freeman ◽  
Kathleen G. Lanzer ◽  
Tres Cookenham ◽  
Bjoern Peters ◽  
John Sidney ◽  
...  

ABSTRACT Murine gammaherpesvirus 68 (γHV68) provides an important experimental model for understanding mechanisms of immune control of the latent human gammaherpesviruses. Antiviral CD8 T cells play a key role throughout three separate phases of the infection: clearance of lytic virus, control of the latency amplification stage, and prevention of reactivation of latently infected cells. Previous analyses have shown that T-cell responses to two well-characterized epitopes derived from ORF6 and ORF61 progress with distinct kinetics. ORF6487-specific cells predominate early in infection and then decline rapidly, whereas ORF61524-specific cells continue to expand through early latency, due to sustained epitope expression. However, the paucity of identified epitopes to this virus has limited our understanding of the overall complexities of CD8 T-cell immune control throughout infection. Here we screened 1,383 predicted H-2b-restricted peptides and identified 33 responses, of which 21 have not previously been reported. Kinetic analysis revealed a spectrum of T-cell responses based on the rapidity of their decline after the peak acute response that generally corresponded to the expression patterns of the two previously characterized epitopes. The slowly declining responses that were maintained during latency amplification proliferated more rapidly and underwent maturation of functional avidity over time. Furthermore, the kinetics of decline was accelerated following infection with a latency-null mutant virus. Overall, the data show that γHV68 infection elicits a highly heterogeneous CD8 T-cell response that segregates into two distinctive kinetic patterns controlled by differential epitope expression during the lytic and latency amplification stages of infection.


2010 ◽  
Vol 84 (20) ◽  
pp. 10923-10927 ◽  
Author(s):  
Michael Molloy ◽  
Weijun Zhang ◽  
Edward Usherwood

ABSTRACT Interleukin-2 (IL-2) has been implicated as being necessary for the optimal formation of primary CD8+ T cell responses against various pathogens. Here we have examined the role that IL-2 signaling plays in several aspects of a CD8+ T cell response against murine gammaherpesvirus 68 (MHV-68). Exposure to MHV-68 causes a persistent infection, along with infectious mononucleosis, providing a model for studying these processes in mice. Our study indicates that CD25 is necessary for optimal expansion of the antigen-specific CD8+ T cell response but not for the long-term memory response. Contrastingly, IL-2 signaling through CD25 is absolutely required for CD8+ T cell mononucleosis.


2007 ◽  
Vol 88 (7) ◽  
pp. 1896-1905 ◽  
Author(s):  
Romana Hochreiter ◽  
Catherine Ptaschinski ◽  
Steven L. Kunkel ◽  
Rosemary Rochford

Many viruses have evolved mechanisms to evade host immunity by subverting the function of dendritic cells (DCs). This study determined whether murine gammaherpesvirus-68 (γHV-68) could infect immature or mature bone-marrow-derived DCs and what effect infection had on DC maturation. It was found that γHV-68 productively infected immature DCs, as evidenced by increased viral titres over time. If DCs were induced to mature by exposure to LPS and then infected with γHV-68, only a small percentage of cells was productively infected. However, limiting-dilution assays to measure viral reactivation demonstrated that the mature DCs were latently infected with γHV-68. Electron microscopy revealed the presence of capsids in the nucleus of immature DCs but not in mature DCs. Interestingly, infection of immature DCs by γHV-68 did not result in upregulation of the co-stimulatory molecules CD80 and CD86 or MHC class I and II, or induce cell migration, suggesting that the virus infection did not induce DC maturation. Furthermore, γHV-68 infection of immature DCs did not result in elevated interleukin-12, an important cytokine in the induction of T-cell responses. Finally, lipopolysaccharide and poly(I : C) stimulation of γHV-68-infected immature DCs did not induce increases in the expression of co-stimulatory molecules and MHC class I or II compared with mock-treated cells, suggesting that γHV-68 infection blocked maturation. Taken together, these data demonstrate that γHV-68 infection of DCs differs depending on the maturation state of the DC. Moreover, the block in DC maturation suggests a possible immunoevasion strategy by γHV-68.


2009 ◽  
Vol 83 (9) ◽  
pp. 4700-4703 ◽  
Author(s):  
Kathleen A. Stuller ◽  
Emilio Flaño

ABSTRACT CD4 T cells are critical for the control of gammaherpesvirus persistence, but their direct effector mechanisms of virus control in vivo are still poorly understood. In this study, we use murine gammaherpesvirus 68 (γHV68) in in vitro and in vivo cytotoxicity assays to show CD4-dependent killing of γHV68-loaded cells in mice persistently infected with γHV68. Our results underscore the cytotoxic capacity of CD4 T cells during γHV68 persistence.


Sign in / Sign up

Export Citation Format

Share Document