- Email: [email protected]
Adoptive immunotherapy of HIV and CMV
advanced
drug delivery reviews
ELSEVIER
Advanced
Adoptive M.J. Gilbert*, Fred Hutchinson
Drug
Reviews
Center,
of HIV and CMV
University of Washington, Seaftle, WA 9819.5, USA Corporation. Seattle, WA, USA
Antigen-specific T cells, which recognize processed fragments of foreign proteins presented in association with major histocompatability complex molecules, represent an essential component of the host response to most intracellular infectious agents and tumors [l-3]. The principle of modulating host T cell responses for therapeutic benefit has been demonstrated by the adoptive transfer of antigen-specific T cells to establish or augment immunity in animal models [4-61. Application of this approach to the treatment of human disease requires the isolation and propagation of human T cells specific for antigens expressed by pathogens, and the successful transfer and survival of these functional T cells in vivo. Studies in our laboratory have focused on developing T cell transfer for viral disease such as CMV and HIV, and on improving the survival and function of these cells in vivo. Adoptive immunotherapy in immunosuppressed individuals was developed in bone marrow transplant (BMT) recipients. Cytomegalovirus (CMV) disease in allogeneic BMT recipients occurs as a consequence of the immunodeficiency induced by the ablative conditioning regimen and post-transplant immunosuppressive therapy [7]. Prior studies have demonstrated that the endogenous recovery of CD8’ Class I MHCrestricted CMV-specific cytotoxic T cell (T,) author.
016Y-409X/95/$29.00 @ 1995 Elsevier SSDl 0169.409X(95)00071-2
359-362
K.S. Watanabe, L. Finch, B.H. Nelson, S.D. Lupton, P.D. Greenberg
Accepted
* Corresponding
17 (1995)
immunotherapy
S.R. Riddell, Cancer Research
Delivery
Science
B.V. All rights
June
R.W. Overell,
and Targeted
Genetics
1995
responses following allogeneic BMT correlates with protection from CMV disease [8,9]. Moreover, the immunodominant CD8’ T, response to CMV in healthy CMV seropositive individuals with protective immunity has been identified and is specific for viral antigens introduced into the cytoplasm of infected cells immediately following viral penetration, resulting in target lysis prior to viral gene expression and new virion assembly [lo]. Therefore, such CD8’ CMV-specific T, clones from CMV seropositive bone marrow donors have been isolated, characterized and propagated in vitro, and evaluated for the potential for reconstituting immunity to CMV in the immunodeficient HLA-identical recipient by adoptive T cell transfer during the period of high infectious risk [ll]. Fourteen patients have been treated with 4 escalating weekly doses (3.3 X lo’/ m* to 1 X 109/m2) of CMV-specific CTL clones beginning 28-42 days post-transplant. All 56 T cell infusions were well tolerated with no alterations in vital signs, oximetry, or graft versus host disease status. The patients have been followed by functional analysis of CMV reactivity present in peripheral blood lymphocytes to determine the efficacy of T cell transfer in reconstituting immunity to CMV. Six patients with weak CMVspecific CD8’ T, responses prior to therapy had augmentation of these responses following T cell transfer. Eight patients had undetectable CMVspecific CD8’ T, and CD4’ T,, responses prior reserved
to therapy-reconstitution of the CD8’ T, (but not CD4’ T,,) response was demonstrable 2 days following infusion of the first dose (3.3 X 107/m2) of CD8’ T, clones. Persistent CD8’ T, were detectable at the time of the next infusion and the magnitude of the response was augmented with each subsequent infusion. Responses equivalent to or greater than those present in the healthy CMV seropositive bone marrow donor were detected in all patients following the third infusion. After completion of four infusions (total cell dose 1.5 X lO’/m’), CD8’ T, clones were detected for up to 12 weeks by analysis of the T cell receptor gene rearrangements present in CMV-reactive T,. clones derived from treated patients and those employed in transferred clones. The successful transfer of immunity to CMV has encouraged the development of a similar protocol for restoring or augmenting T cell immunity to HIV in HIV seropositive patients. Targeting Tc for tissues expressing HIV proteins can lead to toxicity after cell transfer due to inflammation induced following recognition and lysis of HIV-infected cells residing in the CNS, lungs or bone marrow. For these reasons, the clones used in therapy are modified by retrovirus-mediated gene transfer to express a marker gene and an inducible suicide gene - the herpes virus thymidine kinase gene (HSV-TK) [14]. In addition, this genetic modification permits a detailed analysis of in vivo survival of transferred T cells and allows eradication of T, in vivo if toxicity occurs. Preliminary experiments have demonstrated that CD8’ HIVspecific T,. clones are efficiently transduced with an amphotropic retrovirus encoding hygromycin phosphotransferase and HSV-TK. Hygromycinresistant cells are isolated by subcloning with hygromycin selection and such subclones retain MHC-restricted specificity for HIV antigens. Exposure of transduced T cell clones to low concentrations of ganciclovir in vitro results in a dose- and time-dependent cell death. Experiments in murine models have shown that murine T cell clones transduced to express HSV-TK are selectively ablated in vivo with ganciclovir. A clinical protocol has been initiated to study the ability of autologous gene-modified, gag-specific
T cells to augment HIV-specific immunity in healthy HIV-seropositive individuals with CD4 counts between 200 and 500 in the absence of BMT. Six individuals have been enrolled as part of this Phase I study. Each individual has received four escalating doses of gag-specific T cell clones (1.5 X lO’/m’ to 3.3 X lO”/m’) to evaluate T cell survival after transfer, and to establish the effectiveness of low dose ganciclovir to ablate infused T cells, as well as to assess the effect of adoptive transfer of gag-specific T cells on HIV replication and host immune function. The use of adoptive transfer of CD8’ T cell responses as therapy for HIV is based on the fact that HIV-specific CD8’ cytotoxic T cell responses have been shown to provide prolonged survival in HIV seropositive individuals in whom these cells are detectable, but these responses have been demonstrated to be dysfunctional during early stages of disease and lost during late infection with HIV due to the weak or absent T helper cell response to HIV antigens. To extend adoptive T cell therapy for CMV disease to individuals with HIV infection, initial studies in our laboratory have analyzed PBMC for CMVspecific T cell responses from individuals with CMV retinitis, AIDS without CMV disease, and those with CD4 counts between 200 and 500 without disease. In contrast to BMT recipients in whom the development of CMV disease is associated with the absence of detectable CMV-specific CD8’ T,. in vitro, T,. specific for CMV can be isolated from PBMC of individuals with CMV retinitis but at low precursor frequencies. In vitro isolation of CMV-specific T,. from these individuals did require exogenous IL-2 supplementation, suggesting that IL-2 production from CMV-specific T cells was limiting. This was supported by the absence of proliferative T cell responses to CMV antigen in this group. Thus, in HIV infected individuals, the development of effective adoptive therapy may require the introduction of genes into CD8’ T,. that can provide T helper cytokines, such as IL-2, or the transfer of CMV-specific CD4 + T cells that possess genes capable of limiting HIV replication, such as ribozymes or RNA decoy sequences. This latter strategy has already been evaluated in preclinical studies using primary human T cells.
M.J. Gilbert et al. I Advanced
Drug Delivery Reviews 17 (1995) 3-59-362
The expression of selected foreign genes within cells to prevent the replication of HIV has been termed, intracellular immunization (ICimm), and proposed as a mechanism to preserve CD4 + cells in individuals infected with HIV While IC-imm genes specific for HIV have been shown to effectively inhibit viral replication in transformed CD4 + T cell lines in vitro, the effect of these genes on T helper (Th) function and HIV replication in primary antigen-specific CD4 + Th has not been evaluated. Studies with five selected IC-imm genes: (1) a transdominant mutant of rev; (2) a decoy element for rev; 3) a decoy element for tat; (4) a double ribozyme; and (5) a single ribozyme; and transduced antigen-specific CD4 + Th clones isolated from 4 HIV seronegative donors with each gene for evaluation of Th function and HIV infection. Transduced clones stimulated with antigen demonstrated no difference in thymidine incorporation, the expression of CD3, CD4, CD8 ‘, CD25, HLADR surface receptors, and secretion of IL2, IL-4, yIFN relative to control Th. To evaluate the ability of each IC-imm gene to improve survival and preserve Th function after exposure to HIV, transduced Th clones were stimulated in vitro with autologous, antigen-pulsed APC, incubated with HIVBru_LA, (0.1 MOI) for 24°C restimulated with antigen every other week for 10 weeks. Clones were analyzed for proliferation by serial counts of viable cells, HIV replication by quantification of p24 antigen, and surface receptor and cytokine expression. Control Th clones demonstrated high levels of p24 antigen synthesis (>2000 pg/cell) and viable cells were no longer present by 4 weeks post HIV exposure. Th clones expressing each of the IC-imm genes demonstrated consistent rates of proliferation (approx. 2-6 fold/stimulation) over the 10 weeks after exposure to HIV, although this was approximately l/3 to l/2 the rate observed with uninfected cells. Th with IC-imm genes produced markedly less p24 antigen relative to infected controls, but the persistence of detectable p24 suggested that viral replication continued at a low level. Cytokine and cell surface receptor expression were similar for each of the transduced Th clones surviving exposure to HIV Thus, preclinical studies have demonstrated that
361
the expression of these IC-imm genes does not interfere with normal CD4 + T cell function in uninfected cells, and can limit viral replication without affecting antigen-specific function. The success of this strategy in vivo would provide a novel therapy for individuals with HIV and CMV infection, and improve the feasibility and therapeutic efficacy of adoptive immunotherapy in individuals with HIV infection with cytotoxic T cell clones.
References Howes. E.L.. Taylor, W., Mitchison. N.A. and Simpson, E. (1979) MHC matching shows that at least two T-cell subsets determine resistance to HSV Nature 277. 66-68. Braciale. T.J., Morrison, L.A.. Sweetser. M.L.. Sambrook. J., Gething. M.J. and Bracialc, VL. (1987) Antigcn presentation pathways to class I and class II MHC-restricted T lymphocytes. Immunol. Rev. Y8. YS114. Townsend, A. and Bodmer. H. (1989) Antigen recognition by class I-restricted T lymphocytes. Annu. Rev. Immunol. 7. 601-624. Lukacher, A.E., Braciale. V.L. and Braciale, T.J. (19X4) In viva effector function of intluenza virus-specifc cytotoxic T lymphocyte clones is highly specific. J. Exp. Med. 160. 814U326. Lin. Y.L. and Askonsas, B.A. (1981) Biological properties of an infuenza A virus-specitic killer T cell clone. Inhibition of virus replication in viva and induction of delayed-type hypersensitivity reactions. J. Exp. Med. I S4. 225234. Greenberg, P.D. (1991) In: F. Dixon (Ed.). Advanced in Immunology, Academic Press. Orlando, FL, pp. 2X0355. Meyers, J.D.. Bowden, R.A. and Counts. G.W. ( 19X7) In: H. Lode and M. Melzahn (Eds), Infections in Transplant Patients. Georg Thieme Verlag, Stuutgart, pp. 17-32 Macher, A.M., Riechert. C.M., Straus, S.C.. Longo, D.L., Parillo, J., Lane, H.C.. Fauci, A.S.. Rook. A.H.. Manischewutz. J.F. and Quinnan. (I.V. (lY8i) Death in the AIDS patient: role of cytomegalovirus. N. Engl. J. Med. 309. 1354. Reusser. P.. Riddell. S.R.. Meyers, J.D. ;and Grcenbcrg. P.D. ( 1991) Cytotoxic T-Iymphocytc rcsponsc to cytomegalovirus after human allogeneic bone marrow transplantation: pattern of recovery and correlation with cytomegalovirus infection and disease. Blood 78. 137X1.380. Riddell. S.R.. Rabin. M., Geballe. A.P., Britt. W.J. and Greenberg, P.D. (1991) Class I MHC-restricted cytotoxic T lymphocyte recognition of cells infected with human cytomegalovirus does not require endogenous viral gene expression. J. Immunol. 146. 27952804.
362 [ll]
M.J. Gilbert et al.
I Advanced Drug Delivery Reviews 17 (199-f) .l.TY-.i@
Riddell, S.R., Watanabe, KS.. Goodrich, J.M., Li. C‘.-R., Agha. M.E. and Greenberg, P.D. (1992) Restoration of viral immunity in immunodeticient humans by the adoptive transfer of T cell clones [see comments]. Science 257. 238-241. [ 121 Riddell, S.R., Greenberg. P.D.. Overcll, R.W., Loughran. T.P., Gilbert. M.J.. Lupton, SD.. Agosti, J., Scheller. S.. Coombs, R.W. and Corey, L. (1992) Phase I study of cellular adoptive immunotherapy using genetically moditied CD8+ HIV-specific T ceils for HIV seropositive patients undergoing allogeneic bone marrow transplant. Hum. Gene Ther. 3, 319-338.
[ 131 Holland, H.K., Saral, R., Rossi, J.J., Donnenberg, A.D.. Burns. W.H., Beschorner, W.E.. Farzadegan, H., Jones, R.J., Quinnan, G.V. and Vogelsang, G.B. (1989) Allogeneic bone marrow transplantation, zidovudine, and human immunodeficiency virus type 1 (HIV-l) infection. Studies in a patient with non-Hodgkin lymphoma. Ann. Intern. Med. 111, 973-981. [14] Lupton, S.D.. Bruton. L.L., Kalkey. VA. and Overell, R.W. (1991) Dominant positive and negative selection using a hygromycin phosphototransferase-thymidine kinase fusion gene. Mol. Cell. Biol. 11. 3374-3378.
drug delivery reviews
ELSEVIER
Advanced
Adoptive M.J. Gilbert*, Fred Hutchinson
Drug
Reviews
Center,
of HIV and CMV
University of Washington, Seaftle, WA 9819.5, USA Corporation. Seattle, WA, USA
Antigen-specific T cells, which recognize processed fragments of foreign proteins presented in association with major histocompatability complex molecules, represent an essential component of the host response to most intracellular infectious agents and tumors [l-3]. The principle of modulating host T cell responses for therapeutic benefit has been demonstrated by the adoptive transfer of antigen-specific T cells to establish or augment immunity in animal models [4-61. Application of this approach to the treatment of human disease requires the isolation and propagation of human T cells specific for antigens expressed by pathogens, and the successful transfer and survival of these functional T cells in vivo. Studies in our laboratory have focused on developing T cell transfer for viral disease such as CMV and HIV, and on improving the survival and function of these cells in vivo. Adoptive immunotherapy in immunosuppressed individuals was developed in bone marrow transplant (BMT) recipients. Cytomegalovirus (CMV) disease in allogeneic BMT recipients occurs as a consequence of the immunodeficiency induced by the ablative conditioning regimen and post-transplant immunosuppressive therapy [7]. Prior studies have demonstrated that the endogenous recovery of CD8’ Class I MHCrestricted CMV-specific cytotoxic T cell (T,) author.
016Y-409X/95/$29.00 @ 1995 Elsevier SSDl 0169.409X(95)00071-2
359-362
K.S. Watanabe, L. Finch, B.H. Nelson, S.D. Lupton, P.D. Greenberg
Accepted
* Corresponding
17 (1995)
immunotherapy
S.R. Riddell, Cancer Research
Delivery
Science
B.V. All rights
June
R.W. Overell,
and Targeted
Genetics
1995
responses following allogeneic BMT correlates with protection from CMV disease [8,9]. Moreover, the immunodominant CD8’ T, response to CMV in healthy CMV seropositive individuals with protective immunity has been identified and is specific for viral antigens introduced into the cytoplasm of infected cells immediately following viral penetration, resulting in target lysis prior to viral gene expression and new virion assembly [lo]. Therefore, such CD8’ CMV-specific T, clones from CMV seropositive bone marrow donors have been isolated, characterized and propagated in vitro, and evaluated for the potential for reconstituting immunity to CMV in the immunodeficient HLA-identical recipient by adoptive T cell transfer during the period of high infectious risk [ll]. Fourteen patients have been treated with 4 escalating weekly doses (3.3 X lo’/ m* to 1 X 109/m2) of CMV-specific CTL clones beginning 28-42 days post-transplant. All 56 T cell infusions were well tolerated with no alterations in vital signs, oximetry, or graft versus host disease status. The patients have been followed by functional analysis of CMV reactivity present in peripheral blood lymphocytes to determine the efficacy of T cell transfer in reconstituting immunity to CMV. Six patients with weak CMVspecific CD8’ T, responses prior to therapy had augmentation of these responses following T cell transfer. Eight patients had undetectable CMVspecific CD8’ T, and CD4’ T,, responses prior reserved
to therapy-reconstitution of the CD8’ T, (but not CD4’ T,,) response was demonstrable 2 days following infusion of the first dose (3.3 X 107/m2) of CD8’ T, clones. Persistent CD8’ T, were detectable at the time of the next infusion and the magnitude of the response was augmented with each subsequent infusion. Responses equivalent to or greater than those present in the healthy CMV seropositive bone marrow donor were detected in all patients following the third infusion. After completion of four infusions (total cell dose 1.5 X lO’/m’), CD8’ T, clones were detected for up to 12 weeks by analysis of the T cell receptor gene rearrangements present in CMV-reactive T,. clones derived from treated patients and those employed in transferred clones. The successful transfer of immunity to CMV has encouraged the development of a similar protocol for restoring or augmenting T cell immunity to HIV in HIV seropositive patients. Targeting Tc for tissues expressing HIV proteins can lead to toxicity after cell transfer due to inflammation induced following recognition and lysis of HIV-infected cells residing in the CNS, lungs or bone marrow. For these reasons, the clones used in therapy are modified by retrovirus-mediated gene transfer to express a marker gene and an inducible suicide gene - the herpes virus thymidine kinase gene (HSV-TK) [14]. In addition, this genetic modification permits a detailed analysis of in vivo survival of transferred T cells and allows eradication of T, in vivo if toxicity occurs. Preliminary experiments have demonstrated that CD8’ HIVspecific T,. clones are efficiently transduced with an amphotropic retrovirus encoding hygromycin phosphotransferase and HSV-TK. Hygromycinresistant cells are isolated by subcloning with hygromycin selection and such subclones retain MHC-restricted specificity for HIV antigens. Exposure of transduced T cell clones to low concentrations of ganciclovir in vitro results in a dose- and time-dependent cell death. Experiments in murine models have shown that murine T cell clones transduced to express HSV-TK are selectively ablated in vivo with ganciclovir. A clinical protocol has been initiated to study the ability of autologous gene-modified, gag-specific
T cells to augment HIV-specific immunity in healthy HIV-seropositive individuals with CD4 counts between 200 and 500 in the absence of BMT. Six individuals have been enrolled as part of this Phase I study. Each individual has received four escalating doses of gag-specific T cell clones (1.5 X lO’/m’ to 3.3 X lO”/m’) to evaluate T cell survival after transfer, and to establish the effectiveness of low dose ganciclovir to ablate infused T cells, as well as to assess the effect of adoptive transfer of gag-specific T cells on HIV replication and host immune function. The use of adoptive transfer of CD8’ T cell responses as therapy for HIV is based on the fact that HIV-specific CD8’ cytotoxic T cell responses have been shown to provide prolonged survival in HIV seropositive individuals in whom these cells are detectable, but these responses have been demonstrated to be dysfunctional during early stages of disease and lost during late infection with HIV due to the weak or absent T helper cell response to HIV antigens. To extend adoptive T cell therapy for CMV disease to individuals with HIV infection, initial studies in our laboratory have analyzed PBMC for CMVspecific T cell responses from individuals with CMV retinitis, AIDS without CMV disease, and those with CD4 counts between 200 and 500 without disease. In contrast to BMT recipients in whom the development of CMV disease is associated with the absence of detectable CMV-specific CD8’ T,. in vitro, T,. specific for CMV can be isolated from PBMC of individuals with CMV retinitis but at low precursor frequencies. In vitro isolation of CMV-specific T,. from these individuals did require exogenous IL-2 supplementation, suggesting that IL-2 production from CMV-specific T cells was limiting. This was supported by the absence of proliferative T cell responses to CMV antigen in this group. Thus, in HIV infected individuals, the development of effective adoptive therapy may require the introduction of genes into CD8’ T,. that can provide T helper cytokines, such as IL-2, or the transfer of CMV-specific CD4 + T cells that possess genes capable of limiting HIV replication, such as ribozymes or RNA decoy sequences. This latter strategy has already been evaluated in preclinical studies using primary human T cells.
M.J. Gilbert et al. I Advanced
Drug Delivery Reviews 17 (1995) 3-59-362
The expression of selected foreign genes within cells to prevent the replication of HIV has been termed, intracellular immunization (ICimm), and proposed as a mechanism to preserve CD4 + cells in individuals infected with HIV While IC-imm genes specific for HIV have been shown to effectively inhibit viral replication in transformed CD4 + T cell lines in vitro, the effect of these genes on T helper (Th) function and HIV replication in primary antigen-specific CD4 + Th has not been evaluated. Studies with five selected IC-imm genes: (1) a transdominant mutant of rev; (2) a decoy element for rev; 3) a decoy element for tat; (4) a double ribozyme; and (5) a single ribozyme; and transduced antigen-specific CD4 + Th clones isolated from 4 HIV seronegative donors with each gene for evaluation of Th function and HIV infection. Transduced clones stimulated with antigen demonstrated no difference in thymidine incorporation, the expression of CD3, CD4, CD8 ‘, CD25, HLADR surface receptors, and secretion of IL2, IL-4, yIFN relative to control Th. To evaluate the ability of each IC-imm gene to improve survival and preserve Th function after exposure to HIV, transduced Th clones were stimulated in vitro with autologous, antigen-pulsed APC, incubated with HIVBru_LA, (0.1 MOI) for 24°C restimulated with antigen every other week for 10 weeks. Clones were analyzed for proliferation by serial counts of viable cells, HIV replication by quantification of p24 antigen, and surface receptor and cytokine expression. Control Th clones demonstrated high levels of p24 antigen synthesis (>2000 pg/cell) and viable cells were no longer present by 4 weeks post HIV exposure. Th clones expressing each of the IC-imm genes demonstrated consistent rates of proliferation (approx. 2-6 fold/stimulation) over the 10 weeks after exposure to HIV, although this was approximately l/3 to l/2 the rate observed with uninfected cells. Th with IC-imm genes produced markedly less p24 antigen relative to infected controls, but the persistence of detectable p24 suggested that viral replication continued at a low level. Cytokine and cell surface receptor expression were similar for each of the transduced Th clones surviving exposure to HIV Thus, preclinical studies have demonstrated that
361
the expression of these IC-imm genes does not interfere with normal CD4 + T cell function in uninfected cells, and can limit viral replication without affecting antigen-specific function. The success of this strategy in vivo would provide a novel therapy for individuals with HIV and CMV infection, and improve the feasibility and therapeutic efficacy of adoptive immunotherapy in individuals with HIV infection with cytotoxic T cell clones.
References Howes. E.L.. Taylor, W., Mitchison. N.A. and Simpson, E. (1979) MHC matching shows that at least two T-cell subsets determine resistance to HSV Nature 277. 66-68. Braciale. T.J., Morrison, L.A.. Sweetser. M.L.. Sambrook. J., Gething. M.J. and Bracialc, VL. (1987) Antigcn presentation pathways to class I and class II MHC-restricted T lymphocytes. Immunol. Rev. Y8. YS114. Townsend, A. and Bodmer. H. (1989) Antigen recognition by class I-restricted T lymphocytes. Annu. Rev. Immunol. 7. 601-624. Lukacher, A.E., Braciale. V.L. and Braciale, T.J. (19X4) In viva effector function of intluenza virus-specifc cytotoxic T lymphocyte clones is highly specific. J. Exp. Med. 160. 814U326. Lin. Y.L. and Askonsas, B.A. (1981) Biological properties of an infuenza A virus-specitic killer T cell clone. Inhibition of virus replication in viva and induction of delayed-type hypersensitivity reactions. J. Exp. Med. I S4. 225234. Greenberg, P.D. (1991) In: F. Dixon (Ed.). Advanced in Immunology, Academic Press. Orlando, FL, pp. 2X0355. Meyers, J.D.. Bowden, R.A. and Counts. G.W. ( 19X7) In: H. Lode and M. Melzahn (Eds), Infections in Transplant Patients. Georg Thieme Verlag, Stuutgart, pp. 17-32 Macher, A.M., Riechert. C.M., Straus, S.C.. Longo, D.L., Parillo, J., Lane, H.C.. Fauci, A.S.. Rook. A.H.. Manischewutz. J.F. and Quinnan. (I.V. (lY8i) Death in the AIDS patient: role of cytomegalovirus. N. Engl. J. Med. 309. 1354. Reusser. P.. Riddell. S.R.. Meyers, J.D. ;and Grcenbcrg. P.D. ( 1991) Cytotoxic T-Iymphocytc rcsponsc to cytomegalovirus after human allogeneic bone marrow transplantation: pattern of recovery and correlation with cytomegalovirus infection and disease. Blood 78. 137X1.380. Riddell. S.R.. Rabin. M., Geballe. A.P., Britt. W.J. and Greenberg, P.D. (1991) Class I MHC-restricted cytotoxic T lymphocyte recognition of cells infected with human cytomegalovirus does not require endogenous viral gene expression. J. Immunol. 146. 27952804.
362 [ll]
M.J. Gilbert et al.
I Advanced Drug Delivery Reviews 17 (199-f) .l.TY-.i@
Riddell, S.R., Watanabe, KS.. Goodrich, J.M., Li. C‘.-R., Agha. M.E. and Greenberg, P.D. (1992) Restoration of viral immunity in immunodeticient humans by the adoptive transfer of T cell clones [see comments]. Science 257. 238-241. [ 121 Riddell, S.R., Greenberg. P.D.. Overcll, R.W., Loughran. T.P., Gilbert. M.J.. Lupton, SD.. Agosti, J., Scheller. S.. Coombs, R.W. and Corey, L. (1992) Phase I study of cellular adoptive immunotherapy using genetically moditied CD8+ HIV-specific T ceils for HIV seropositive patients undergoing allogeneic bone marrow transplant. Hum. Gene Ther. 3, 319-338.
[ 131 Holland, H.K., Saral, R., Rossi, J.J., Donnenberg, A.D.. Burns. W.H., Beschorner, W.E.. Farzadegan, H., Jones, R.J., Quinnan, G.V. and Vogelsang, G.B. (1989) Allogeneic bone marrow transplantation, zidovudine, and human immunodeficiency virus type 1 (HIV-l) infection. Studies in a patient with non-Hodgkin lymphoma. Ann. Intern. Med. 111, 973-981. [14] Lupton, S.D.. Bruton. L.L., Kalkey. VA. and Overell, R.W. (1991) Dominant positive and negative selection using a hygromycin phosphototransferase-thymidine kinase fusion gene. Mol. Cell. Biol. 11. 3374-3378.