ABSTRACT
Since T cells play a critical role in collagen-induced arthritis (CIA), CD4+ T cell hybridomas were derived from DBA/1 mice immunized with bovine type II collagen (CII). The hybrid clones selected were Thy-1-2+, CD4+, CD8-, T cell receptor (TcR) alpha beta + and produced interleukin-2 in response to CII peptides presented by I-Aq molecules. The clones were collagen type-specific and recognized CII from many species except the mouse. More precisely, the reactivity was directed against the immunodominant cyanogen bromide-cleaved fragment CB11(II). Analysis of the TcR carried by the T cell hybridomas showed that they used identical V alpha and J alpha (V alpha BMB, J alpha 20) gene segments and two distinct V beta (V beta 1 and V beta 4) associated with the J beta 2.5 gene segment. Interestingly, the junctional regions were highly conserved in structure and length. These findings may indicate a strong in vivo selection by the antigen for a particular combination of both alpha and beta chains of the TcR. Inoculation of irradiated anti-CII T cell hybrids into DBA/1 mice, before priming with CII, altered the course of the disease resulting in either a long-lasting suppression or an exacerbation of CIA whereas a control CD4+ hybridoma with an unrelated specificity did not influence the development of arthritis. However, the regulatory effect of anti-CII T cell clones was unpredictable, suggesting that the TcR structure may not solely account for the modulation of CIA and that T cell vaccination is not a reliable method for inducing suppression of CIA.
Subject(s)
Arthritis/etiology , CD4-Positive T-Lymphocytes/physiology , Collagen/immunology , Immunotherapy, Adoptive , Amino Acid Sequence , Animals , Arthritis/therapy , Base Sequence , CD4-Positive T-Lymphocytes/immunology , Epitopes , Histocompatibility Antigens Class II/immunology , Hybridomas/immunology , Mice , Mice, Inbred C3H , Mice, Inbred CBA , Mice, Inbred DBA , Molecular Sequence Data , Receptors, Antigen, T-Cell, alpha-beta/chemistry , Receptors, Antigen, T-Cell, alpha-beta/geneticsABSTRACT
The locus encoding mouse TCR-alpha chain includes approximately 100 V alpha gene segments that can be organized in about 20 structural subfamilies. Southern blot analysis of a T cell line derived from the BALB/c strain, M5T, has indicated that both alpha loci were rearranged, as assessed by the deletion of the delta locus, and that the V alpha gene segment involved in one of the rearrangements did not belong to any of the V alpha subfamilies already described. Transcripts of TCR-alpha chains from the M5T line were cloned after cDNA synthesis and anchored-polymerase chain reaction, revealing a V alpha gene segment of an as yet unidentified subfamily, V alpha 5T. Molecular cloning of germ-line V alpha 5T gene segments has shown that this subfamily contained two members, one of them being a pseudogene. The two members were located to each extremity of the alpha locus associated with a member of the V alpha 13 and V alpha BWB subfamilies. Analysis of transcripts bearing the V alpha 5T gene segment in the M5T line as well as in thymocytes has revealed that J alpha are frequently absent. This is due to an alternate donor splice site generated at the V alpha 5T-J alpha junction that leads to a splicing from the end of V alpha 5T to C alpha instead of the J alpha to C alpha conventional splicing. The impact of J alpha spliced-out transcripts on the allelic exclusion process is discussed.
