Differential Recognition of Altered Peptide Ligands Distinguishes Two Functionally Discordant (Arthritogenic and Nonarthritogenic) Autoreactive T Cell Hybridoma Clones

Abstract

Intravenous injection of a cartilage proteoglycan (aggrecan)-specific Th1 hybridoma clone 5/4E8 induced joint lesions similar to those seen in either primary or adoptively transferred arthritis in BALB/c mice. A sister clone, TA20, recognizing the same peptide epitope of human aggrecan and using the same Vβ4 and Vα1 segments, failed to induce joint inflammation. This study examines the fine epitope specificities of these two clones. Both 5/4E8 and TA20 hybridomas were generated using T cells from the same arthritic animal that has been immunized with human aggrecan, and both clones recognized peptides containing a consensus GRVRVNSAY sequence. However, flanking regions outside this nonapeptide sequence region had differential impact on peptide recognition by the two clones. Similarly, when single amino acid substitutions were introduced to the consensus sequence, significant differences were detected in the epitope recognition patterns of the T cell hybridomas. The 5/4E8 hybridoma showed greater flexibility in recognition, including a higher responsiveness to the corresponding self (mouse) aggrecan peptide, and produced more inflammatory cytokines (IFN-γ and TNF-α), whereas hybridoma TA20 produced IL-5 in response to either human or mouse self peptide stimulation. These results demonstrate that, within the pool of immunodominant (foreign) peptide-activated lymphocytes, marked individual differences of degeneracy exist in T cell recognition, with possible implications to autopathogenic T cell functions.

Nonself-Antigens Are the Cognate Specificities of Foxp3+ Regulatory T Cells

“…However, T cell hybridomas made from autoreactive T cells continued to manifest the original self-reactivity in vitro and for years T cell hybridomas were used for detecting weak and strong agonists, sometimes at very low levels (Hampl et al, 1997;Grubin et al, 1997). In general, the self-reactive hybridomas are produced either after antigen priming or from autoimmune prone strains but not directly from naive TCR repertoire, which is expected to have a very low frequency of autoreactive T cells (Yanoma et al, 1988;Buzas et al, 2003).…”

Presentation of the candidate rheumatoid arthritis autoantigen aggrecan by antigen‐specific B cells induces enhanced CD4+ T helper type 1 subset differentiation

“…40) (VVLLVATEGRVRVNSAYQDK), containing the core (underlined) arthritogenic CD4 + T cell epitope from the G1 domain of bovine and human aggrecan, was synthesized by JPT Peptide Technologies GmbH (Berlin, Germany). (Note: peptide p89-103 (ATEGRVRVNSAYQDK) has previously been numbered p70-84 36,41 by excluding residues comprising the signal sequence. )…”

Identification of Novel Human Aggrecan T Cell Epitopes in HLA-B27 Transgenic Mice Associated with Spondyloarthropathy

“…Interestingly, the sequence no. 56 (GRVRVNSAY) of this negative pool was recently reported as a consensus sequence in longer immunogenic peptide sequences recognized by aggrecan-specific CD4 ϩ Th1 cell hybridomas derived from immunized BALB/c mice (36). However, from our experiments, the human aggrecan sequence GRVRVNSAY does not seem to evoke CD8 ϩ T cell responses.…”