I-J as an idiotype of the recognition component of antigen-specific suppressor T-cell factor.
The I-J determinant of membrane glycoprotein is known to be expressed exclusively on suppressor T cells (TS), which have a crucial role in the regulation of immune responses. I-J also comprises part of the soluble factor (TSF) with suppressor activity which is secreted from TS. Gene-mapping experiments have indicated that the I-J gene lies between the I-A and I-E subregions of the mouse major histocompatibility complex (MHC) and is defined by the H-2 congeneic pair, that is, B10.A(3R) and B10.A(5R). In fact, antibodies raised in the reciprocal combinations of B10.A(3R) and B10.A(5R) define the I-Jb and I-Jk alleles, and are able to detect the I-J determinants on TS and TSF. Biochemical and functional analyses, using I-J-positive TS clones and hybridomas, have demonstrated that monoclonal anti-I-J antibodies precipitate I-Jk or I-Jb with a relative molecular mass of 25,000-28,000 (25-28K) and that the I-J+ molecule mediates the restriction specificity of TSF in association with an antigen-binding protein (45K). However, molecular genetic studies on the I-J gene reveal no genetic difference between B10.A(3R) and B10.A(5R) and also that there is no room to accommodate a gene encoding I-J in the expected I region. These discrepancies between the molecular genetic and serological/functional data require explanation. Here we demonstrate that TS and TSF expressing I-J of the host type were produced by fully allogeneic bone marrow cells of donor origin in chimaeric mice, when the chimaeras received the host antigen-presenting cells (APC) at the time of immunization. The results show that APC are necessary for the activation and clonal expansion of TS and also support the notion that I-J is an idiotypic determinant of the recognition component of TS and TSF.
T
T
Sumida
T
T
Sado
M
M
Kojima
K
K
Ono
H
H
Kamisaku
M
M
Taniguchi
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D002678:Chimera; D002874:Chromosome Mapping; D000939:Epitopes / Q000235:genetics*; D006183:H-2 Antigens / Q000235:genetics*; D008222:Lymphokines / Q000235:genetics* / Q000276:immunology; D008285:Major Histocompatibility Complex; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D010641:Phenotype; D013491:Suppressor Factors, Immunologic
D000939:Epitopes; D006183:H-2 Antigens; D008222:Lymphokines; D013491:Suppressor Factors, Immunologic