Red blood cell-mediated delivery of recombinant HIV-1 Tat protein in mice induces anti-Tat neutralizing antibodies and CTL.
The immunotherapeutic potential of biologically active HIV-1 Tat protein coupled to autologous red blood cells (RBCs) was evaluated in a mouse model. HIV-1 Tat expressed in Escherichia coli and purified to homogeneity was found to be active in viral trans activation and efficiently internalised by monocyte-derived dendritic cells (MDDCs). The product of HIV-Tat biotinylation and coupling to RBCs by means of a biotin-avidin-biotin bridge, (RBC-Tat), showed no trans activation activity and was still efficiently internalized by MDDCs as compared to uncoupled Tat.Balb/c mice were then immunized with 10 microg of soluble Tat in complete Freund's adjuvant or with 40 ng of Tat coupled on RBCs surface and boosted at week 3, 6 and 25 with 5 microg soluble Tat in incomplete Freund's adjuvant or with 20 ng of RBC-coupled Tat, respectively. Anti-Tat antibody response was similar in both groups; however, 2/6 animals immunized with soluble Tat and 6/6 animals immunized with RBC-Tat developed anti-Tat neutralizing antibodies. In addition, at week 28 cytolytic anti-Tat CTLs were detected in all animals although they were slightly higher in mice immunized with RBC-Tat. These results indicate that RBC-mediated delivery of HIV-1 Tat, in amounts 250 times lower than soluble Tat, is safe and induces specific CTL responses and neutralizing antibodies.
Dominici
S
S
Institute of Biochemistry Giorgio Fornaini, University of Urbino, Via Saffi 2, 61029 Urbino, Italy.
Laguardia
M E
ME
Serafini
G
G
Chiarantini
L
L
Fortini
C
C
Tripiciano
A
A
Brocca-Cofano
E
E
Scoglio
A
A
Caputo
A
A
Fiorelli
V
V
Gavioli
R
R
Cafaro
A
A
Ensoli
B
B
Magnani
M
M
D016915:AIDS Vaccines / Q000008:administration & dosage / Q000276:immunology*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D019921:Biotinylation; D017707:Erythrocyte Transfusion; D015696:Gene Products, tat / Q000235:genetics* / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D007115:Immunization Schedule; D051379:Mice; D011994:Recombinant Proteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014182:Transplantation, Autologous; D054322:tat Gene Products, Human Immunodeficiency Virus
D016915:AIDS Vaccines; D000914:Antibodies, Viral; D015696:Gene Products, tat; D011994:Recombinant Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus