Replication-defective canarypox (ALVAC) vectors effectively activate anti-human immunodeficiency virus-1 cytotoxic T lymphocytes present in infected patients: implications for antigen-specific immunotherapy.
In the attempt to develop immunotherapeutic strategies for acquired immunodeficiency syndrome capable of activating effector cells in an antigen-specific manner while maintaining the broadest possible T-cell repertoire, we evaluated two canarypox (ALVAC)-based vectors for their capacity to induce ex vivo activation/expansion of human immunodeficiency virus (HIV)-specific CD8+ cytotoxic lymphocyte precursors (CTLp) obtained from HIV-1-infected donors. These two vectors, vCP205 encoding HIV-1 gp120 + TM (28 amino acid transmembrane anchor sequence) in addition to Gag/protease and vCP300 encoding gp120 + Gag/protease as well as Nef and Pol CTL determinants, are pancytotropic but replication incompetent in mammalian cells. Bulk peripheral blood mononuclear cells (PBMCs) or enriched CD8+ T cells were stimulated for 10 days with autologous ALVAC-infected PBMCs in the presence of different cytokine combinations (interleukin-2 [IL-2], IL-4, IL-7, and IL-12). Activation by ALVAC constructs was highly antigen-specific, because vCP205 elicited only Env and Gag CTL, whereas vCP300 elicited broader reactivities against Env, Gag, Pol, and Nef determinants. The ALVAC activation of CTLp was IL-2 dependent and enhanced by the addition of IL-7, whereas IL-4 and IL-12 failed to augment cytotoxic reactivities elicited by these constructs. The expansion of enriched CD8+ T cells after activation with vCP300 was higher in patients with CD4 counts greater than 400 cells/microL. Two rounds of in vitro stimulation (IVS) with vCP300 resulted in nearly an eightfold expansion of CD8+ lymphocytes over a 25-day period. After the second IVS, an average 3.2-fold increase among the different antigen-specific CTL frequencies was achieved. These studies clearly show that HIV-recombinant ALVAC vectors represent powerful polyvalent antigenic stimuli for activation and expansion of the CD8 lymphocyte response that occurs as a result of HIV infection.
Ferrari
G
G
Department of Surgery, Duke University Medical Center, Durham, NC 27710-2996, USA.
Berend
C
C
Ottinger
J
J
Dodge
R
R
Bartlett
J
J
Toso
J
J
Moody
D
D
Tartaglia
J
J
Cox
W I
WI
Paoletti
E
E
Weinhold
K J
KJ
D000328:Adult; D018150:Avipoxvirus / Q000276:immunology*; D016207:Cytokines / Q000494:pharmacology; D003673:Defective Viruses; D005822:Genetic Vectors; D015488:HIV Antigens / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology* / Q000628:therapy; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D007167:Immunotherapy / Q000379:methods*; D008213:Lymphocyte Activation / Q000187:drug effects; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
C078788:ALVAC vaccine; D016207:Cytokines; D015488:HIV Antigens; D014765:Viral Vaccines