Immunogenicity of the Human Immunodeficiency Virus (HIV) Recombinant nef Gene Product. Mapping of T-Cell and B-Cell Epitopes in Immunized Chimpanzees (original) (raw)
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Journal of Virology
In 8 of 12 experimentally infected macaques, the Nef SIVmac 251 protein was recognized by cytolytic T lymphocytes (CTL) and appeared strongly immunogenic. Here, we report experiments which have been performed by using synthetic peptides to precisely determine the epitopes recognized by macaque CTL. Three epitopes of the Nef protein have been defined as CTL targets in three macaques. The epitopic peptides are located in the central region of the protein, and all of them show high homology with peptides of the human immunodeficiency virus type 1 Nef protein recognized by human CTL in association with several human leukocyte antigen molecules. These results suggest that (i) the Nef protein is a good candidate for vaccination not only because of its early expression but also because of its high immunogenicity for CTL, (ii) long peptides covering the central region of this protein could be used as vaccines and could cross the major histocompatibility complex barrier in a large variety of...
Vaccine, 1993
Because T-cell responses are critical for defence against viral infections, an ideal vaccine should stimulate these cells. The authors have examined a series of forty overlapping synthetic peptides covering the entire amino acid sequence of the envelope protein gp120 from the human immunodeficiency virus type I ( HIV-1) HTL V-IIIB isolate,for harbouring putative T-cell recognition sites. The peptide-induced proliferative responses and IL-2 production by blood mononuclear cells were studied from 40 macaques previously immunized with ovalbumin-conjugated HIV-1 peptide(s). These analyses disclosed four major areas of T-cell recognition, including one novel T-cell activating region (located between amino acids 152 and 176) which was also found to harbour a domain recognized by HIV-1 neutralizing antibodies. Recognition of the latter region by CD4 + T cells did not appear to be subject to strong genetic restriction. The results of these studies have obvious implications for the development of synthetic subunit vaccines against the acquired immunodeficiency syndrome (AIDS).
AIDS Research and Human Retroviruses, 1995
This article describes the impact of sequence variation on the distribution and seroreactivity of linear antigenic epitopes in gpl20 encoded in new Ugandan HIV-1 clones from subtypes A, C, and D, and in North American clones from the B subtype. A region of the env gene encoding the C2 to V5 domains was PCR amplified from the lysates of peripheral blood leukocytes or from short-term cultured isolates. Computer-assisted analyses were conducted on the amino acid sequences to determine the distribution of surface structures in gpl20. Despite marked sequence diversity, eight analogous epitopes were predicted for all clades of the virus analyzed. Synthetic peptides comprising the putative principal neutralizing determinant E2[V3], and other B cell epitopes E3[V3-V4], E4[V3-V4], E7[C3], and E8[V5], from a seroprevalent Ugandan isolate, AUG06c, were tested in ELISA for antigenicity with sera from Uganda, New York, and Thailand. Variable magnitudes of seroreactivity were observed for all of the peptides tested. However, a significantly higher degree of serum cross-reactivity was detected with the V3 loop peptide. ELISA reactivities of the same serum panel indicated that V3 loop peptides containing the apical residues GPGR (clones AUG06c and BRT3) or GPGQ (CUG045 and DUG044) were more antigenic and display extensive cross-reactivity as compared to analogous peptides comprising GLGQ (DUG23c), GQGQ (DUG042), or GPWG (BRT1). BETATURN analysis of the divergent V3 loop apical residues showed a good correlation of probable jS-turn occurrence with strong seroreactivity. These findings suggest that the major antigenic specificities in the divergent clades of HIV-1 are well conserved. Serological analysis of the epitopes encoded in the variant HIV-1 isolates could complement the current search for a broadly reactive candidate vaccine.
Vaccine, 1998
A colinearly synthesized peptide consisting of a H-2d restricted T-helper cell epitope of Semliki Forest virus (SFV) and triple repeats of sequence GPGRAF, derived from the V3 domain of HIV-1 strains, was used to immunize BALB/c (H-2d) mice. Pepscan analysis of sera from peptide-immunized mice revealed that the chimaeric peptide GREKFTIRPHYGKEIGPGRAFGPGRAFGPGRAF contains three distinct antibody-reactive sequences GREKFTIR, PHYGKEI and GPGRAF. The chimaeric peptide evoked HIV-1 IIIb neutralizing antibodies in serum as measured in vitro by reduction of syncytia formation and reduction of p24 production as well. So, the T-helper cell epitope of SFV provided help to a small linear neutralization epitope of HIV-1 strains. Interestingly, the T-helper cell epitope alone might induce antibodies cross-reactive with HIV-1 IIIb specific peptide GPGRAFVTIGK which shows some homology (residues underlined) with the antibody-reactive sequence GREKTIR of SFV.
A Comparative Study of Different Presentation Strategies for an HIV Peptide Immunogen
Bioconjugate Chemistry, 2004
Different strategies have been used to increase the immunogenicity of an antigenic HIV peptide as a vaccine candidate. The selected B-cell epitope comprises 15 amino acids (317-331) of the V3 region of HIV-1, JY1 isolate (subtype D), in tandem with a T-helper epitope corresponding to the 830-844 region of tetanus toxoid. Several presentations, including oligomerization, multiple antigenic peptide dendrimers, and conjugation to dextran beads or to other macromolecular carriers, have been synthesized and evaluated. Murine sera from the different presentations of the V3 epitope have been compared with regard to antibody titers and cross-reactivity with heterologous HIV subtypes. The dendrimer version of the peptide conjugated to HBsAg protein was a better immunogen than the dendrimer alone and showed a higher immunogenicity than other multimeric presentations or than the peptide alone conjugated to dextran. The dendrimer version, either alone or conjugated to HBSAg, enhanced cross-reactivity toward heterologous V3 sequences relative to monomeric peptide. In addition, fine epitope mapping of the entire JY1 sequence by sera from the different immunization groups was performed by the spot synthesis technique. Results showed that the amino acids involved in molecular recognition were LXQXXY or LXQXLY, with particularly strong recognition of the C-terminal region LGQALY. However, cross-reactivity toward the heterologous sequences did not completely correlate with recognition of particular amino acids in the primary sequences. These results can find application in the development of HIV vaccine candidates.
1992
Abstract--In this report, we assess the humoral immune response in inbred strains of mice immunized with baculovirus-derived recombinant HIV-l gpl60 (rgpl60). Six inbred strains of mice were each immunized with two different concns (5 and 50 pg) of rgp160, and the antibody response to rgp160 and synthetic peptides which define distinct gpl60 epitopes was examined. Within a given inbred strain of mice, no significant difference in antibody titers to gp160 was observed in those groups receiving either 5 or 50~8 of rgp160 per injection. Following three immunizations with rgpl60, differences in anti-gp160 titers were observed among the various inbred strains; however, these differences became less apparent after additional injections with rgp160. In addition, each mouse strain exhibited a unique reactivity pattern to seven gp160 epitopes defined by synthetic peptides. Multiple injections with rpgl60 were required to induce responses to certain gp160 epitopes. The observed differences in...