Identification of a major human immunodeficiency virus‐1 reverse transcriptase epitope recognized by mouse CD4⁺ T lymphocytes

Abstract

Delineation of major T helper cell recognition sites of human immunodeficiency virus (HIV-1) proteins represents one important step in the design of an efficient acquired immune deficiency syndrome (AIDS) vaccine. Towards this end, we have explored the immunogenicity of HIV-1BRU proteins in the mouse model. Preliminary experiments revealed that inbred mice primed with whole inactivated HIV-1 developed strong CD4+ T cell proliferative responses to a variety of recombinant viral proteins including reverse transcriptase (RT). To characterize further the mouse T cell responses to this protein, several Ad- or Ed-restricted T hybridoma cells (THC) were established from BALB/c or DBA/2 mice. These THC were tested for their capacity to recognize a series of 15-mer synthetic overlapping peptides spanning three segments of HIV-1 RT that had been preselected on the basis of either alpha-helicity, amphipaticity, and/or for containing rare amino acid sequence patterns. Peptides corresponding to a C-terminal region (residues 528-560) of RT were recognized by several of the THC established from RT-primed mice. Furthermore, a non-alpha-helical peptide from this region (A3, 528-543) was capable of priming mice with different H-2 haplotypes for both peptide A3 and native RT CD4+ T cell recognition. In addition to the recently identified RT determinant 203-219 capable of triggering both mouse and human CD8+ CTL, the present results identify a good candidate for an immunodominant RT epitope capable of eliciting RT-specific T helper cell responses.

Identification and Antigenicity of Broadly Cross-Reactive and Conserved Human Immunodeficiency Virus Type 1-Derived Helper T-Lymphocyte Epitopes

“…Similar approaches have been used to identify HTL epitopes from other HIV-1 antigens (8,14,41). In fact, one of the epitopes examined herein, Pol 711, has been demonstrated to be immunogenic in mice (19). While these studies have illustrated that there is an overlap between mice and humans in the recognition of class II-restricted epitopes, it is likely that many human epitopes would be undetected with this approach.…”

Fusion to Flaviviral Leader Peptide Targets HIV-1 Reverse Transcriptase for Secretion and Reduces Its Enzymatic Activity and Ability to Induce Oxidative Stress but Has No Major Effects on Its Immunogenic Performance in DNA-Immunized Mice

“…RT1.14opt-in- and RT1.14oil-immunized mice demonstrated similar levels of cellular response against the recombinant RT1.14 protein (Figure 7(a)). Immunization with DNA encoding RT1.14opt-in and RT1.14oil induced a weak IFN- γ and IL-2 response against a CD4 + T cell epitope of RT localized at aa 528-543 [45], which tended to be stronger in mice DNA immunized with RT1.14oil (Figure 7(b), p < 0,1). Peptides representing other known epitopes of RT induced no specific IFN- γ or IL-2 production (data not shown).…”

Oxidative stress induced by HIV-1 reverse transcriptase modulates the enzyme’s performance in gene immunization

“…Injections were followed by electroporation (Derma Vax, Cellectis). On day 23 post immunization, mice were sacrificed, splenocytes were isolated and stimulated by a peptide representing the immunodominant murine T-cell epitope of RT (aa 528-543 42 ), recombinant RT1.14 protein or positive and negative control antigens ( Fig. 5A-C and data not shown).…”