Immunization of human HIV-seronegative volunteers with recombinant p17/p24:Ty virus-like particles elicits HIV-1 p24-specific cellular and humoral immune responses.
OBJECTIVE
To evaluate the immune response to HIV-1 p24 generated in vivo by p17/p24:Ty virus-like particles (p17/p24:Ty-VLP) by examining the lymphoproliferative and antibody (Ab) responses to HIV-1 p24, as well as Gag-specific cytotoxic T lymphocytes (CTL), in HIV-seronegative volunteers immunized with hybrid p17/p24:Ty-VLP.


METHODS
Sixteen HIV-seronegative volunteers were immunized with p17/p24:Ty-VLP at two dose levels (100 or 500 micrograms) and monitored for the following 48 weeks for production of anti-p24 and anti-p17 Ab, in vitro lymphoproliferative responses to HIV-1 p24 and p17, and in vitro CTL responses to HIV-1 Gag.


RESULTS
Twelve out of the 16 volunteers had significant p24-specific proliferative responses, with volunteers on the higher dose schedule exhibiting earlier proliferative responses than those on the lower dose schedule. Proliferative responses in both volunteer groups were similar in overall magnitude but appeared at different times during the immunization schedule. Anti-p24 Ab were detected in six out of the nine individuals in the lower dose group and in five out of the seven in the higher dose group. There was a good correlation between the presence of p24-specific Ab and the detection of lymphoproliferative responses to the p24 protein in peripheral blood mononuclear cells isolated from the same individuals. Anti-p17 Ab were detected in five volunteers. No Gag-specific CTL responses were detected.


CONCLUSIONS
We conclude that hybrid HIV-1 p17/p24:Ty-VLP are capable of inducing both cellular and humoral immunity to HIV-1 Gag p17 and p24 components and are worthy of further study as a potential HIV immunotherapeutic.
Martin
S J
SJ
Department of Immunology, University College London Medical School, UK.
Vyakarnam
A
A
Cheingsong-Popov
R
R
Callow
D
D
Jones
K L
KL
Senior
J M
JM
Adams
S E
SE
Kingsman
A J
AJ
Matear
P
P
Gotch
F M
FM
D016915:AIDS Vaccines / Q000009:adverse effects / Q000276:immunology*; D015683:Gene Products, gag / Q000276:immunology*; D015483:HIV Antibodies / Q000096:biosynthesis*; D015488:HIV Antigens / Q000276:immunology*; D016655:HIV Core Protein p24 / Q000276:immunology*; D018023:HIV Seronegativity; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008297:Male; D011994:Recombinant Proteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus
D016915:AIDS Vaccines; D015683:Gene Products, gag; D015483:HIV Antibodies; D015488:HIV Antigens; D016655:HIV Core Protein p24; D011994:Recombinant Proteins; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054858:p17 protein, Human Immunodeficiency Virus Type 1