Immune responses elicited by recombinant vaccinia-human immunodeficiency virus (HIV) envelope and HIV envelope protein: analysis of the durability of responses and effect of repeated boosting.
Previous studies indicate that immunization with recombinant (r) vaccinia-human immunodeficiency virus type 1 (HIV-1) gp160 and boosting with baculovirus-derived HIV-1 rgp160 results in stronger cellular and antibody responses than those following either vaccine alone. The durability of immunity over 1 year was evaluated in 12 recipients. Both cellular and binding antibody responses remained detectable but diminished, and neutralizing antibodies were absent. To boost immunity, rgp160 was given again 1 year after the initial boost. Reboosting elicited strong HIV-specific lymphoproliferative responses. Binding antibody levels also rose dramatically, and the magnitude of the peak responses was significantly greater following the 2-year than following the 1-year boost. However, neutralizing antibody titers were low (1:10-1:20) and detected in only 4 of 12 persons. Moreover, persistent CD8+ cytolytic responses were not induced. Thus, although repeated rgp160 boosting after vaccinia-envelope priming can augment selected immune components, an altered regimen may be necessary to achieve protective long-term immunity to HIV-1.
McElrath
M J
MJ
Department of Medicine, University of Washington School of Medicine, Seattle.
Corey
L
L
Berger
D
D
Hoffman
M C
MC
Klucking
S
S
Dragavon
J
J
Peterson
E
E
Greenberg
P D
PD
D016915:AIDS Vaccines / Q000276:immunology*; D016367:Baculoviridae / Q000235:genetics; D015153:Blotting, Western; D016827:CD8 Antigens / Q000096:biosynthesis; D005500:Follow-Up Studies; D015686:Gene Products, env / Q000276:immunology*; D015483:HIV Antibodies / Q000096:biosynthesis; D019302:HIV Envelope Protein gp160; D015658:HIV Infections / Q000517:prevention & control; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D007124:Immunoenzyme Techniques; D008213:Lymphocyte Activation; D008297:Male; D011498:Protein Precursors / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology*; D014616:Vaccinia virus / Q000235:genetics
D016915:AIDS Vaccines; D016827:CD8 Antigens; D015686:Gene Products, env; D015483:HIV Antibodies; D019302:HIV Envelope Protein gp160; D011498:Protein Precursors; D014614:Vaccines, Synthetic