We have generated an mAb, RR3-15, that recognizes murine TCRs containing the V beta 11 domain. Using this antibody to stain peripheral T cells, we have demonstrated that V beta 11-bearing T cells are largely absent from strains of mice that express the class II MHC molecule, I-E. Studies with F1 mice demonstrate that this effect is dominant, consistent with tolerance. The clonal deletion of V beta 11-bearing T cells appears to occur intrathymically, as immature but not mature V beta 11+ T cells are present in the thymus of I-E-bearing mice. Examination of B6 x DBA/2 recombinant inbred strains demonstrates that the expression of I-E molecules is necessary for the clonal deletion of V beta 11-bearing T cells, but that other non-MHC genes control the clonal deletion process, as well. Paradoxically, only a small fraction of V beta 11+ T cell hybridomas are I-E reactive.

No abstract

9G4+ IgG Abs expand in systemic lupus erythematosus (SLE) in a disease-specific fashion and react with different lupus Ags including B cell Ags and apoptotic cells. Their shared use of VH4-34 represents a unique system to understand the molecular basis of lupus autoreactivity. In this study, a large panel of recombinant 9G4+ mAbs from single naive and memory cells was generated and tested against B cells, apoptotic cells, and other Ags. Mutagenesis eliminated the framework-1 hydrophobic patch (HP) responsible for the 9G4 idiotype. The expression of the HP in unselected VH4-34 cells was assessed by deep sequencing. We found that 9G4 Abs recognize several Ags following two distinct structural patterns. B cell binding is dependent on the HP, whereas anti-nuclear Abs, apoptotic cells, and dsDNA binding are HP independent and correlate with positively charged H chain third CDR. The majority of mutated VH4-34 memory cells retain the HP, thereby suggesting selection by Ags that require this germline structure. Our findings show that the germline-encoded HP is compulsory for the anti–B cell reactivity largely associated with 9G4 Abs in SLE but is not required for reactivity against apoptotic cells, dsDNA, chromatin, anti-nuclear Abs, or cardiolipin. Given that the lupus memory compartment contains a majority of HP+ VH4-34 cells but decreased B cell reactivity, additional HP-dependent Ags must participate in the selection of this compartment. This study represents the first analysis, to our knowledge, of VH-restricted autoreactive B cells specifically expanded in SLE and provides the foundation to understand the antigenic forces at play in this disease.

We have investigated the structure of the murine Y chromosome by first developing a novel method for specifically cloning Y-encoded DNA and then generating a library enriched for Y-specific DNA sequences. Three randomly chosen Y DNA clones were studied and found to share several interesting properties: all three are members of small Y-specific multisequence families; all three are mouse-specific; and all three probes detect Y-encoded restriction fragments that are polymorphic. Examination of polymorphic Y chromosome restriction fragments in male DNA from nine different inbred strains suggests that only two polymorphic forms of Y chromosomal DNA exist among inbred strains of mice.

The kinetics and order of rearrangements in the gene complex encoding T-cell-receptor j3 chains were studied by Southern blot hybridization in a collection of hybridomas derived from fetal thymocytes at various stages of ontogeny (day 14 to day 17). Our results show a steady increase in the frequency of rearranged 18 complexes during this period and suggest that these rearrangements occur within the thymus. g3-chain diversity region (DO3) to fl-chain joining region (J41) joining preceded other types of rearrangements. More complex hybridization patterns consistent with fully rearranged functional f8-chain genes did not begin to accumulate until day 16, 1 day prior to significant surface expression of the receptor protein.