Characterization of murine monoclonal antibodies to the tat protein from human immunodeficiency virus type 1

Abstract

A panel of murine monoclonal antibodies (MAbs) to the human immunodeficiency virus type 1 transactivator tat protein were characterized. The anti-tat MAbs were mapped to the different domains of the tat protein by Western blot (immunoblot) and Pepscan analyses. One-half of the MAbs tested mapped to the amino-terminal proline-rich region, and one-third of the MAbs tested mapped to the lysine-arginine-rich region of tat. The individual MAbs were tested for inhibition of tat-mediated trans activation, using a cell-based in vitro assay system. MAbs which mapped to the amino-terminal region of the tat protein demonstrated the highest degree of inhibition, whereas MAbs reactive to other portions of the molecule exhibited a less pronounced effect on tat function.

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

“…An additional B cell epitope was identified between residues 46-60. 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].…”

“…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cell epitopes was also found in sera of Tat-vaccinated monkeys, as well as in HIV-1-infected individuals ( [32,33] and unpublished data), and that vaccination of monkeys with peptides encompassing these epitopes was able to control chronic viremia after challenge [40].…”

“…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.…”

“…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.…”

Molecular cloning and characterization of the genes encoding the immunoreactive major cell-surface proteins of Porphyromonas gingivalis

“…Very interestingly, the carboxy-terminal region, amino acid residues 498-534, had an extremely high content of proline (40.5%). It has been reported that proline-rich regions exhibit high immunogenicity [15]. This molecular mass was far smaller than that estimated for the purified CSP (72-kDa) from SDS-PAGE analysis.…”