The T-cell receptor in primates: identifying and sequencing new owl monkey TRBV gene sub-groups

Abstract

The New World primate Aotus nancymaae (owl monkey) has been shown to be an excellent experimental model when studying malarial parasites. Characterising the T-cell receptor (TR) alphabeta repertoire by means of the different variable beta (TRBV) genes displayed contributes to a better understanding of these lymphocytes' role in the response against several malarial antigens. This study describes identifying and characterising eleven new TRBV gene sub-groups in cDNA from Aotus nancymaae's peripheral blood lymphocytes; these 11 gene sequences displayed homology to the previously reported human TRBV3, TRBV10, TRBV11, TRBV14, TRBV18, TRBV19, TRBV20, TRBV25, TRBV27, TRBV29 and TRBV30 sub-groups, resulting in 83% overall homology at the amino acid level. An additional Aotus sequence was found having similarity with the human TRBJ-2-7*01 gene. Evolutionary relationships amongst these sequences and the homologous genes from both New and Old World primates have shown that the TRBV repertoire has been maintained in the species being studied, displaying varying association patterns and substitution rates, depending on the sub-group being studied. The degree of identity observed when comparing human and Aotus genes suggests that these species might have a similar TRBV repertoire.

3D Analysis of the TCR/pMHCII Complex Formation in Monkeys Vaccinated with the First Peptide Inducing Sterilizing Immunity against Human Malaria

“…Based on the Aotus Vβ sequences reported to date [10], [11], the spectratyping analysis of the CDR3 amplicons showed a polyclonal Gaussian-like distribution for the majority of TCR Vβ families in the pre-immune (P0) samples ( Figure S1a) typical of unstimulated T cells. The CDR3 size distribution pattern ( Figure S1b ) changed strikingly to skewed oligoclonal expansions of one, two or three dominant Vβ families in Ao191, Ao259, Ao149, Ao250, Ao239, Ao277, Ao142, Ao224 and Ao148 upon immunization with peptide 24112 ; however, such skewed patterns were only associated with high antibody production in Ao191, Ao259, Ao149, Ao250, Ao239 and Ao277.…”

“…Nineteen specific forward primers and a common primer annealing in the β-chain constant (Cβ) region were designed to amplify all Aotus Vβ families reported to date [11]. Additionally, a set of reverse and forward primers amplifying a 419-bp fragment of the Aotus TCR α-chain constant (Cα) segment was used as amplification control ( Table S2 ).…”

“…However, conserved HABPs were found to be neither antigenic nor immunogenic or protection inducers when tested in Aotus monkeys, a non-human primate model highly susceptible to human malarias [8], [9] and whose immune system molecules share a high degree of similarity with their human counterparts, specially with those involved in antigen presentation such as α/β TCRs [10], [11] and MHCII–HLA-DRβ1*-like molecules (88% to 100% similarity is reported for the Peptide binding region or PBR of these molecules) [12].…”

Strategies for developing multi‐epitope, subunit‐based, chemically synthesized anti‐malarial vaccines

“…Sequencing studies of the genes encoding these Aotus Class II molecules (HLA-DR␤1*-like), undertaken in 110 Aotus monkeys, have revealed 100-88% homology with human HLA-DR␤1*04, 03, 08, 11,13,14,15,16,10, 07 and 01 molecules [28] and Ն80-100% homology with human TCRs [29] and other immunesystem molecules [30].…”

Recent advances in the development of a chemically synthesised anti-malarial vaccine

“…Compelling evidence states that Aotus monkeys are an excellent experimental model for malaria research as they are highly susceptible to human malaria [60] and have an immune system which is highly similar to that of humans, as we had already established for > 40% of the most relevant immune system molecule families by gene cloning and DNA sequencing [61][62][63][64][65][66]. The next step was to find out whether the HABPs identified to date could induce a protective immune response inhibiting receptor--ligand interaction between parasite ligands and RBC receptors.…”