Adenovirus-Mediated Gene Transfer of Viral Interleukin-10 Inhibits the Immune Response to Both Alloantigen and Adenoviral Antigen

Abstract

Although adenoviral vectors are attractive for gene transfer, their effectiveness is limited by host antiviral immune responses. In this study, we determined if host antiallograft and antiviral immunity could be diminished with an adenoviral vector encoding the immunosuppressive cytokine viral interleukin-10 (vIL-10). AdSV40vIL-10, a vIL-10-expressing adenoviral vector with an SV40 promoter, induced significant prolongation of murine cardiac allograft survival to 32.2 +/- 1.7 days compared to 14.2 +/- 1.0 days for controls (p < 0.01). This effect was specific for vIL-10 encoding vector and could be inhibited by anti-vIL-10 monoclonal antibody (mAb). In vivo administration of adenovirus facilitated the generation of adenovirus-specific cytotoxic T lymphocytes (CTL), whereas treatment with AdSV40vIL-10 prevented CTL priming and generation of virus-specific immunity. AdSV40vIL-10 also induced extended expression of a beta-galactosidase reporter from a co-injected LacZ-encoding adenoviral vector. These results demonstrate that adenovirus-mediated gene transfer and expression of vIL-10 prolong allograft survival and inhibit the immune response to adenoviral antigens, thereby improving the persistence of the vector and extending transgene expression. The efficacy of adenoviral vectors can be improved by incorporating immunosuppressive genes into the vector.

Lentivirus-mediated gene transfer of viral interleukin-10 delays but does not prevent cardiac allograft rejection

“…Adenoviral vectors are efficient for in vivo delivery of genes to a wide variety of tissue types and do not require target cell replication. The major disadvantage of adenoviral vectors is that the duration of expression is limited by the potent adenovirus-specific immune response directed at the infected cell 23 and the fact that vIL-10 expression is systemic and not restricted to the transplanted tissue. Our results showed that lentiviral vectors can generate sustained gene expression for at least 28 days in a syngeneic cardiac graft.…”

“…Rejection occurred at around day 14. Published work using adenoviral vectors showed that an anti-IL-10 response was not detectable even 10 days postexpression 23 and suggested that the generation of an anticytokine response would itself be inhibited by vIL-10. Studies were conducted to address the kinetics of vIL-10 in promotion of allograft survival.…”

“…In support of our hypothesis, Qin et al 19 showed that retroviral vectors encoding vIL-10 prolong graft survival significantly longer (graft survival to 39.4+2.5 days) than when using adenoviral vector (graft survival to 18.471.2 days). 23 However, this work was performed in a nonvascularized, murine heart transplant model in which T cells likely have delayed activation compared to fully vascularized heart transplants. It is probable that the synergistic effect of a subtherapeutic dose of CsA together with adenovirus-encoded vIL-10 is not entirely due to CsA-mediated inhibition of an adenovirusspecific immune response as reported by others, 21 but instead a result of early suppression of T-cell activation in response to the vascularized allograft.…”

“…35 Irradiated DA lymph node cells, comprising approximately 77% T lymphocytes, 23 were used as stimulators (4 Â 10 5 /well). MLRs were cultured for 5 days in round-bottom 96-well plates at 371C in 5% CO 2 using RPMI 1640 medium (Gibco-BRL) supplemented with 10% FCS, 2 mM L-glutamine (Gibco-BRL), 100 mg/ml streptomycin, 100 U/ml penicillin, 2 mg/ml gentamicin (Gibco-BRL) and 50 mM 2-mercaptoethanol.…”

“…The limited survival benefit observed was suggested to be due to transient gene expression and/or insufficient levels of vIL-10 expression. 23 Alternative vectors, which can achieve more effective and sustained gene expression, are needed if vIL-10 is to be clinically useful.…”