Longitudinal Follow-up of Cellular and Humoral Immunity Induced by Recombinant Adenovirus-Mediated Gene Therapy in Cancer Patients

Abstract

Replication-defective adenoviruses are arousing growing interest as both gene therapy and vaccine vectors. In a phase I clinical trial designed to evaluate the feasibility and tolerance of recombinant adenovirus (rAd)mediated gene transfer, we previously demonstrated that a single intratumoral injection of 10(9) PFU of rAd encoding the beta-galactosidase protein (Ad-beta-Gal) induced strong short-term (1-3 months) humoral, helper (Th1 type) and cytotoxic T cell responses specific for the transgene product in patients with advanced lung cancer. The purpose of the present study was to evaluate the persistence of long-lasting immunity to the transgene protein and in parallel, to assess patient immunocompetence revealed by responses to recall antigens (tetanus toxoid, purified protein derivative), viral pathogens (Epstein-Barr virus, influenza virus), and allogeneic antigens in mixed lymphocytic reactions. The beta-Gal-specific proliferative response declined rapidly in patients with progressive disease, as did responses to the other antigens. In contrast, a long-lasting proliferative response to beta-gal was maintained in an immunocompetent patient in complete remission 2 years after an injection of 108 PFU of Ad-beta-Gal. Anti-beta-Gal humoral (IgG and IgA) responses persisted notably, as did responses to TT and poliomyelytic antigens. While T cell effector cytotoxic responses specific for the viral peptides plummeted, the frequency of anti-beta-Gal CTL precursors remained particularly high, thus attesting to major immunization. Despite the impact of both advanced disease and chemotherapy on immunocompetence, we show the long-term persistence of immunity to the transgene protein vectorized by rAd.

Potential of Equine Herpesvirus 1 as a Vector for Immunization

“…While poxviruses can harbor approximately 25 kbp of foreign genetic material, human herpesviruses can package foreign DNA of more than 100 kbp in size, and the limitations caused by the low packaging capacity intrinsic to the various RNA viruses, adenoviruses, or AAV systems can be overcome by using vaccinia virus, canarypox virus, HSV-1, or HCMV (3,35,45). However, one disadvantage for using human HSV-1, HCMV, EBV, or vaccinia virus as vectors is the fact that many patients have already encountered infection and/or vaccination with, especially, the human herpesviruses (31,32). Because antivector immunity and impaired efficiency of gene transfer can pose serious problems, the development and testing of novel vector systems is one of the keys to successful development of novel and efficacious immunization schemes (46).…”

Generating p53-specific cytotoxic T lymphocytes by recombinant adenoviral vector-based vaccination in mice, but not man

“…In contrast to humoral immune responses specific for adenovirus encoded non-self gene products, such as ␤-galactosidase and suicide proteins, 24,28,29 delivery of p53-recombinant viral vectors into mice 4 and man 30 did not induce Ab responses directed to the self-p53 protein.…”

“…34 Considering that adenoviral backbonereactive Th lymphocyte responses were amplified by rAd/hup53 vaccination, a failure to simultaneously induce p53 transgene-specific Th cells may have thus contributed to the absence of p53-reactive CD8 + T cells responding to A2.1-presented wt p53 epitopes and, in one patient, to p53 protein-labeled DCs. Although the generation of CTLs specific for non-self ␤-galactosidase Ags by injection of a recombinant adenoviral vector has not been prevented by adenovirus-specific Abs, 28,29 we cannot necessarily preclude the possibility that the presence of neutralizing anti-adenoviral Abs in our study patients may have limited the induction of low-and residual high-avidity p53-specific CTLs. Another possibility that could explain the lack of p53-specific T cell responses in our patients results from the recent observation that adenoviral transduction of tumor cells leads to enhanced activation-induced cell death of tumorreactive T lympocytes, which can be partially reverted by…”

Gene therapy for carcinoma of the breast

“…40,41 Several proposed mechanisms include antiangiogenesis, 42 secretion of soluble proapoptotic proteins, 43 and immune upregulation. 44,45 A bystander effect is highly desirable for a therapeutic gene, because it reduces the level of transduction efficiency required for successful gene therapy. 46 Transfer of p53 into lung cancer by an adenoviral vector was initially demonstrated by Zhang et al 47 In this regard, an in vivo study of p53 gene transfer in mouse xenograft breast cancer models displayed significant suppression of tumor growth.…”