A Lipidated Anti-Tat Antibody Enters Living Cells and Blocks HIV-1 Viral Replication

Abstract

We have developed a chemical modification of antibodies, lipidation, which enables their intracellular delivery into living cells. Intracellular localization of lipidated antibodies was demonstrated by confocal microscopy and by measuring cellular uptake of 125I-labeled lipidated antibodies. Functionally, a lipidated monoclonal antibody directed against the Tat protein from human immunodeficiency virus type 1 (HIV-1) inhibited viral replication of several HIV-1 isolates by approximately 85% as shown by increased viability of infected cells and decreased reverse transcriptase activity. The antibody in its native form had no such effect. These data show that lipidated antibodies can reach and functionally inhibit intracellular targets. Lipidation may help to facilitate the development of intracellular immunotherapy for AIDS.

Efficient mucosal delivery of the HIV‐1 Tat protein using the synthetic lipopeptide MALP‐2 as adjuvant

“…The in vivo relevance of these epitopes is also supported by epidemiological data, since it has been recently reported that individuals with anti-Tat antibodies do not appear to progress to AIDS [9,11,12,41,42] and that the presence of high antibody levels to Tat 6-14 , Tat [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] and Tat 46-60 is associated with undetectable viral load [12]. Thus, mucosal vaccination with biologically active Tat protein + MALP-2 induces antibodies against epitopes that are associated with a better prognosis.…”

“…These results are in agreement with previous reports in which B cell linear epitopes were identified in the murine BALB/c system [36,37]. This is an important finding, since in vitro experiments have indicated that mAb against the Nterminal activation domain of Tat protein (Tat 2-21 and Tat [4][5][6][7][8][9][10][11][12] ) and the basic region (Tat 50-62 ) inhibit HIV-1 Tatmediated LTR transactivation, and HIV-1 infection and replication in acutely and persistently infected human CD4 + cells [36,38,39]. Of further importance is the fact that specificity against the same B cell epitopes was also found in sera of Tat-vaccinated monkeys, as well as in HIV-1-infected individuals ( [32,33] and unpublished data), and that vaccination of monkeys with peptides encompassing these epitopes was able to control chronic viremia after challenge [40].…”

“…vaccination with biologically active Tat protein and MALP-2 was also able to induce IFN-+ -producing cells, which constitute a correlate for protection. For this reason, splenocytes from vaccinated animals were incubated for 16 h in the absence or presence of a pool of Tat peptides that were known to be targets for CTL in the murine system (ACTNCYCKKCCFHCQVCFIT [aa [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], WKHPGSQ- [35] and unpublished data), and the number of IFN-+ -secreting cells was determined by ELISPOT. The results demonstrated that the frequency of IFN-+secreting cells was significantly higher in mice vaccinated with Tat protein + MALP-2 than in the other groups (Fig.…”

Induction of Neutralizing Antibodies and Th1-Polarized and CD4-Independent CD8+T-Cell Responses following Delivery of Human Immunodeficiency Virus Type 1 Tat Protein by Recombinant Adenylate Cyclase ofBordetella pertussis

“…These two B-cell epitopes, previously identified in BALB/c mice (7,8,11), are also recognized by monkey and human sera (46,64,66). Interestingly, anti-Tat antibodies against the N-terminal activation domain (amino acids 1 to 20) and the basic region (amino acids 46 to 65) of the Tat protein prevent the HIV-1 Tat transactivating capacity as well as HIV-1 replication and infection (8,15,50). Taken together, our results show that immunization with Tat delivered by the CyaA vector without adjuvant induces a high Tat-specific antibody production, demonstrating its capacity to be an efficient vector to generate a long-lasting and neutralizing humoral response.…”

Review of Current Cell-Penetrating Antibody Developments for HIV-1 Therapy

“…To evaluate its clinical use, the humanized version of anti-Tat antibody (sFvhutat2) was constructed and its antiviral effect has been shown in primary HIV-1 isolate-challenged PBMCs [ 27 ]. Meanwhile, another group has chemically modified the anti-Tat antibody by lipidation and these modified antibodies inhibited various HIV-1 isolates up to 85% [ 72 ].…”