Genetic markers of the antigen-specific T cell receptor locus

The type B leukemogenic virus truncated superantigen is dispensable for T-cell lymphomagenesis

Type B leukemogenic virus (TBLV) is a variant of mouse mammary tumor virus (MMTV) that causes T-cell lymphomas in mice. We have constructed a TBLV-MMTV hybrid, pHYB-TBLV, in which 756 bp of the C3H MMTV long terminal repeat (LTR) was replaced with 438 bp of the TBLV LTR. Intraperitoneal injection of pHYB-TBLV transfectants consistently resulted in T-cell lymphomas in 50% of injected weanling BALB/c mice with an average latency period of 5.7 (+/- 1.5) months. Transfectants of pHYB-TBLV containing a double-frameshift mutation in the truncated superantigen gene (sag) induced T-cell lymphomas with similar incidences, latency periods, and phenotypes, suggesting that cis-acting elements in the TBLV LTR determine disease specificity.

Association between susceptibility to Theiler's virus-induced demyelination and T-cell receptor Jbeta1-Cbeta1 polymorphism rather than Vbeta deletion

Theiler's murine encephalomyelitis virus (TMEV) induces demyelinating disease in susceptible mouse strains after intracerebral inoculation. The clinical symptoms and histopathology of the central nervous system appear to be similar to those of human multiple sclerosis (MS), and thus, this system provides an excellent infectious animal model for studying MS. The virus-induced demyelination is immune mediated, and the genes involved in the immune response such as those for the T-cell receptor beta-chain and major histocompatibility complex (MHC) haplotypes are known to influence disease susceptibility. To define whether the T-cell receptor Jbeta-Cbeta or Vbeta genes are associated with susceptibility, we have analyzed F2 mice from crosses of susceptible SJL/J (Vbeta(a)-JCbeta(b)) mice and resistant C57L (Vbeta(a)-JCbeta(a)) mice. Our results indicate that susceptibility to TMEV-induced demyelination is associated with restriction fragment length polymorphism reflecting the T-cell receptor Jbeta1-Cbeta1 region rather than the Vbeta polymorphism. This association becomes stronger when the MHC haplotype is considered in the linkage analysis. However, differences in the T-cell receptor alpha-chain haplotype have no significant influence on the pathogenesis of TMEV-induced demyelination.

T cell receptor V beta gene utilization in myelin basic protein specific clones from CXJ1 recombinant inbred mice

CXJ1 mice are a recombinant inbred strain generated from experimental allergic encephalomyelitis (EAE) resistant BALB/c and EAE susceptible SJL/J progenitors. CXJ1 derive their major histocompatibility complex (MHC) class II and TCR genes from the BALB/c progenitor. However, their susceptibility to EAE is similar to SJL/J. Utilizing myelin basic protein (MBP)-specific CD4+ hybridoma clones and a MBP-specific T cell line (TCL) from CXJ1, we found the predominant T cell receptor (TCR) V beta chain expression to be V beta 8 and V beta 13. Our data support the concept of preferential, but not exclusive, TCR V beta usage in the MBP-specific response which is independent of MHC class II haplotype or immunodominant peptide.

B lymphocytes from hyporesponsive SJL mice contain aberrant nucleoside binding sites

C8-substituted guanine ribonucleosides activate B cells by a novel pathway that apparently is independent of GTP-binding proteins and protein kinase C. B lymphocytes from SJL mice are hyporesponsive to antigen-independent inductive signals transmitted by these nucleosides. In the current studies, the basis for this observation was explored. Responses of normal murine strains to these agents have been dissociated into antigen-independent (inductive) and antigen-dependent (differentiative) types by use of the 7,8-disubstituted guanine ribonucleosides. Dose-response profiles for inductive responses appear to correlate with apparent Kd values for low-affinity nucleoside binding sites; dose-response curves for antigen-dependent differentiative responses correlate with apparent Kd values for high-affinity binding sites. It was found that the SJL low-affinity site exhibits an apparent Kd that is approximately 10- to 20-fold lower in affinity for 8BrGuo than that of normal CBA mice. Although the low-affinity site in normal murine strains displays nearly equivalent affinity toward C8-substituted and 7,8-disubstituted nucleosides, the low-affinity site of SJL mice binds 7,8-disubstituted compounds with approximately 5-fold higher affinity than it does monosubstituted compounds. The dissociation constant for high-affinity nucleoside binding sites of SJL mice was only slightly different from that of CBA mice, consistent with the observation of essentially normal antigen-dependent nucleoside-mediated activity in SJL mice. The current observations support (a) a role for low-affinity binding sites in antigen-independent inductive events, (b) a role for high-affinity binding sites in antigen-dependent differentiative events mediated by substituted guanine nucleosides, and (c) the existence of aberrant low-affinity binding sites in B cells from SJL mice.

Prp (proline-rich protein) genes linked to markers Es-12 (esterase-12), Ea-10 (erythrocyte alloantigen), and loci on distal mouse chromosome 6

The closely linked proline-rich protein (Prp) genes, coding for abundant salivary proteins, are located on distal mouse chromosome 6. They are part of a conserved linkage group that is represented on human chromosome 12p. Two other markers, Ea-10 and Es-12, that were previously unassigned to a chromosome are closely linked to Prp genes in the mouse.

T-cell receptor-specific monoclonal antibodies against a V beta 11-positive mouse T-cell clone

Two monoclonal antibodies specific for the mouse T-cell receptor (Tcr) have been established by immunization with a V beta 11+ T-cell clone, clone C6. One is a rat antibody, KT11 (IgG2b, k), specific for the V beta chain of C6, V beta 11. This was demonstrated by the fact that the strain distribution pattern of KT11+ cells was similar to that of V beta 5, 8, 9, 11, 12, and 13 and that the gene that encodes the molecule detected by KT11 was closely linked to V beta 8 in (B10 X SJL)F1 X SJL backcross mice. Furthermore, V beta of C6 has been cloned from a lambda gt10 cDNA library and was demonstrated to be identical to the V beta 11 published sequences. All strains of mice that do not express major histocompatibility complex class II E molecules had higher numbers of KT11+ cells than E+ strains. The KT11+ population in A strain mice and its H-2 congenic strains, however, was not affected by the presence or absence of E molecules. The other is a mouse antibody, KTL2 (IgM), specific for the idiotope of the Tcr expressed on the clone C6. Both antibodies were mitogenic and induced cytotoxicity. Expression of epitopes detected by KT11 or KTL2 was down-modulated by a T3 epsilon-specific antibody 145-2C11.

Preferential expression of fibronectin receptors on immature thymocytes

Fibronectin-adherent (FNR+) thymocytes are enriched for immature (CD4-8-) and large (CD4+8+) cells, and depleted of mature (CD4-8+ and CD4+8-) and nonmature small (CD4+8+) cells. Among purified CD4-8- thymocytes, cells with the surface marker J11d and the IL-2 receptor, which can give rise to all other thymocyte subsets, showed selective attachment to fibronectin. Analysis of FNR+ thymocytes showed that such cells are greatly enriched for cells in cycle. Additionally, FNR+ cells expressed low levels of T cell receptor. These results suggest a role for the fibronectin receptor during the early, proliferative phase of thymocyte differentiation. The data suggest that loss of the fibronectin receptor is a hallmark of cells that have become committed either to functional maturation or to programmed cell death.

Clonal diversity of myelin basic protein-specific T lymphocytes

A panel of myelin basic protein (MBP)-specific, class II major histocompatibility complex (As)-restricted T-cell clones were established from SJL/J mice. Three clonotypes, based on their responses to guinea pig MBP and its peptide fragments, were observed. Clonotype I cells, represented by clones HS.6, HS.D2, HS.8, HS.E10, and HS.C1, were reactive to the encephalitogenic C-terminal fragment of MBP, amino acid residues 89-169. Clonotype II, represented by clone HS.E3, was reactive to fragments containing residues 43-88, and clones HS.D12 and HS.C7, representing clonotype III cells, responded to the whole molecule only. Three clones from clonotype I were capable of transferring both clinical and histological signs of experimental allergic encephalomyelitis (EAE) into naive mice. Southern blot analysis of T-cell receptor beta-chain genes using J beta 1- and J beta 2-specific probes showed that the rearrangement pattern was unique in each of the clones. These results suggest that the development of EAE may represent an autoaggressive polyclonal T-cell response.

Alpha/beta T-cell antigen receptor gene and protein expression occurs at early stages of thymocyte differentiation

Alterations in gene expression that orchestrate eukaryotic cellular differentiation often require appropriate interactions between differentiating cells and a specialized microenvironment. During T-lymphocyte differentiation, immature thymocytes undergo a stringent intrathymic selection process that requires intimate contact with thymic stromal elements. Since this selection process generates T cells that are self-tolerant and recognize nominal antigen only within the context of self-major histocompatibility antigen complex molecules, it is possible that thymocyte/stromal cell interactions are mediated, in part, by antigen-specific receptors expressed on differentiating thymocytes. However, the developmental stage at which alpha/beta antigen-specific receptors are expressed during T-cell maturation has been a matter of debate. To address this issue, we have studied alpha/beta T-cell antigen receptor gene and protein expression on normal thymocyte subsets of AKR/J mice, as well as on a panel of AKR/J primary thymic lymphomas characterized for CD4 (L3T4) and CD8 (Lyt-2) differentiation antigen expression. The data unequivocally demonstrate that alpha/beta heterodimers are expressed not only on phenotypically mature thymocytes but also on the majority of CD4+8+ double-positive cells that comprise the predominant nonmature thymocyte subset. Furthermore, a fraction of thymocytes in the CD4-8- double-negative compartment, known to contain progenitor cells, also expresses readily detectable cell-surface alpha/beta receptors. Therefore, during the process of intrathymic selection, interactions between nonmature thymocytes and stromal cells via the antigen-receptor complex may play a pivotal role in T-cell differentiation and should be considered in formulating schemes for functional T-cell selection.

T-cell-receptor beta- and I-A beta-chain genes of normal SWR mice are linked with the development of lupus nephritis in NZB x SWR crosses

The incidence of nephritis in autoimmune New Zealand Black (NZB) mice is low, but when they are crossed with normal SWR mice, almost 100% of the female F1 hybrids (SNF1) develop lethal glomerulonephritis. To define the contribution of the normal SWR strain to the development of nephritis, we analyzed the association of the I-A beta-chain gene of Ia-encoding region, the T-cell-receptor beta (TcR beta)-chain gene, and immunoglobulin heavy-chain allotype (IgH) with the development of lupus nephritis in 165 NZB X SWR crosses. We found that genes linked to the TcR and Ir gene loci of the normal SWR mice interacted with NZB-derived genes, leading to the development of accelerated and severe nephritis in the NZB X SWR crosses.

Effective activation of resting mouse T lymphocytes by cross-linking submitogenic concentrations of the T cell antigen receptor with either Lyt-2 or L3T4

We studied the activation of small resting mouse T lymphocytes by antibodies to the T cell antigen receptor in combination with antibodies to other T cell surface antigens. Solid-phase but not soluble antibodies KJ16-133 and F23.1, both directed to beta chains of the V beta 8 family, activate T cells to proliferate in the presence of growth factors, in a dose-dependent fashion. Antibodies to Lyt-2 and to L3T4 had no activating effect at any concentration. However, submitogenic concentrations of KJ16-133 and of F23.1 synergized with a wide range of concentrations of anti-Lyt-2 and anti-L3T4 to cause T cell proliferation similar or greater in magnitude to that caused by high concentrations of anti-T cell receptor antibody. Synergistic activation was also observed with antibodies to Lyt-1, LFA-1 and H-2 class I antigens but to a significantly lower degree. This was particularly clear in limiting dilution experiments in which the corrected frequencies of T cells proliferating in response to low amounts of anti-T cell receptor antibody together with anti-Lyt-2 were 1/4 to 1/7 for BALB/c T cells. The frequencies of BALB/c T cells responding to high concentrations of anti-T cell receptor antibody alone were between 1/14 and 1/126 and still lower frequencies of T cells proliferated in synergistic responses with anti-LFA-1 or anti-Lyt-1. Synergistic activation leads to the induction of functional cytotoxic cells. We interpret these data as suggestive that cross-linking of the T cell antigen receptor with either Lyt-2 (CD8) or L3T4 (CD4) represents an optimal activating signal for resting T cells. We think that, in physiological T cell activation, cross-linking of the T cell receptor to CD8 or CD4 is induced by their simultaneous binding to major histocompatibility complex (MHC) class I (for CD8) or MHC class II (for CD4) molecules on stimulator cells. We consider the possibility that similar cross-linking requirements may also exist during T cell repertoire selection in ontogeny, thus accounting for the strict coexpression of MHC class I and class II-restricted T cell receptors with CD8 and CD4 molecules, respectively.

A T cell receptor V beta segment that imparts reactivity to a class II major histocompatibility complex product

We have identified in mice an allele of a new T cell receptor V beta gene, V beta 17a, whose product is bound by the monoclonal antibody KJ23a. Over 90% of T cell hybridomas prepared from V beta 17a+ T cells of SWR mice respond to allogeneic forms of the IE class II MHC protein, indicating that V beta 17a has an appreciable affinity for IE regardless of the other components of the T cell receptor. These results suggest a bias in the germ-line T cell receptor repertoire toward recognition of MHC proteins and indicate that the V beta portion of the receptor may form the most important contact points with MHC ligands.

Hybrid antibody-mediated lysis of virus-infected cells

Previously, cytotoxic T lymphocytes (CTL) had only been focused by hybrid antibodies to normal, cell-surface proteins and haptenated surface structures. In this report, we extend the application of this technology to mediate lysing of virus-infected cells by nonspecific CTL. Heteroconjugated antibodies between the anti-T cell antigen receptor antibody, F23.1, and monoclonal antibodies against either the hemagglutinin or nucleoprotein of the influenza virus PR/8 were constructed. We show in the present report that these bispecific constructs can target virus-infected cells for lysis according to the specificity of the virus-protein reactive monoclonal antibodies. Furthermore, even a virus protein that is only expressed in small quantities on the cell surface, such as nucleoprotein, can be exploited as target structure for heteroconjugated antibodies. These studies show that hybrid antibodies can focus a CTL response on virus-infected cells which might in the future be used to mount an immune response in situations without sufficient normal cellular defense.

Restriction fragment length polymorphism of the human T cell receptor alpha gene. I. Two polymorphic restriction sites localized to different regions of the gene

Previous studies have demonstrated restriction fragment length polymorphisms (RFLP) in the vicinity of the alpha and beta genes of the human T-cell receptor. In the course of experiments designed to discover additional polymorphic restriction sites, we found a new RFLP of the T-cell alpha gene recognized by the restriction enzyme Taq I. The site was localized to the interval between the most 3' joining (J) exon and the most 5' constant (C) region exon, about 7 kb distant from the previously described Bgl II polymorphic site which mapped to the vicinity of the 3' untranslated exon. With the use of these two polymorphic markers, four Ti-alpha alleles could be identified, allowing unambiguous assignment of all Ti-alpha genes in some families. These markers may be useful in identifying possible immune response genes or disease predisposition genes associated with the genes of the T-cell receptor for antigen.

T cell receptor expression and receptor-mediated induction of clonal growth in the developing mouse thymus. High surface beta-chain density is a requirement for functional maturity

The ontogeny of T cell antigen receptor expression and function in the mouse thymus has been studied using a monoclonal antibody, F23.1, which recognizes a determinant on the beta chain of the receptor, and stains 25% of mature T cells and around 7-15% of adult thymocytes from most mouse strains. The same monoclonal antibody selectively activates Lyt-2+ peripheral T cells. Receptors are detectable by staining and fluorescence-activated cell sorter analysis from fetal day 17, and thereafter the overall frequency increases steadily towards adult levels. However, late fetal thymocytes express all of their antigen receptor beta chain at a very low level, visible by staining as a "shoulder" on the peak of negative cells. Thymocytes with high-density surface beta chain, visible by staining as a distinct peak, appear only after birth and are a prominent feature at neonatal day 4. In the late fetus, expression of beta chain can be detected on thymocytes with the "mature" L3T4-, Lyt-2+ phenotype. Despite this, F23.1-responsive precursors are not found in the fetal thymus, and appear in two waves, the first during day 1 of postnatal life and the second between days 3 and 4. These data suggest that high-density surface expression of T cell receptor beta chain occurs in parallel with functional maturation.

Molecular genotyping of human T-cell antigen receptor variable gene segments

The gene complex encoding the beta chain of the T-cell antigen receptor (Tcr) in man was previously reported to contain a restriction fragment length polymorphism (RFLP) involving a single Bgl II site adjacent to the second constant region gene. This RFLP allowed assignment of Tcr beta genotypes in certain human families. In the present study, two different RFLP in a V beta gene family were detected using the murine probe V8.1 in genomic DNA samples digested with the restriction endonucleases Hind III and Bam HI. Use of these RFLP to mark the V beta gene complex allowed complete haplotype assignment in four of seven families studied and provided support for linkage of the V gene complex to the constant region genes. Different combinations of the C and two V region markers can result in eight possible distinct haplotypes. The observation of all but one of the eight possible haplotypes in parents of the families studied suggests that recombination events occur between the C and V region and among members of the V region subfamily marked by the V8.1 probe. These markers can be used for mapping studies of the V beta gene complex in man and will allow an appraisal of possible associations between Tcr beta genes and disease susceptibility.

Structure and diversity of the human T-cell receptor beta-chain variable region genes

In order to characterize the variability of the expressed human T-cell receptor (TCR) beta-chain repertoire and contrast this variability to the known murine beta-chain repertoire, 15 independent complementary DNA (cDNA) clones containing TCR beta-chain variable region (V beta) genes were isolated from a human tonsil cDNA library. The nucleotide and derived amino acid sequences of these 15 V beta genes were analyzed together with 7 previously defined sequences. Fifteen different human V beta genes could be identified from 22 independent sequences. By means of DNA hybridization and sequence homology comparisons, it was possible to group these 15 genes into ten distinct V beta subfamilies, each containing from one to seven members. Minimal polymorphism was noted between individuals, except in multimember subfamilies. The amino acid sequences of these genes contain conserved amino acids that are also shared by murine TCR V beta genes and immunoglobulins; no features were found that distinguish human V beta genes from their murine counterparts. Evaluation of secondary structure showed that maximum variability coincides with generally hydrophilic portions of the amino acid sequence, while specific hydrophobic regions were conserved in all V beta genes examined.

The cytotoxic T cell response to the male-specific histocompatibility antigen (H-Y) is controlled by two dominant immune response genes, one in the MHC, the other in the Tar alpha-locus

The genetic control of the cytotoxic T-cell response to the male histocompatibility antigen, H-Y, was analyzed in BALB/cKe(C) and SJL/J(J) which are both nonresponders. However, the (C X J)F1 hybrid is a responder. Therefore, two dominant complementing genes are involved. Analysis of a set of (C X J) recombinant inbred (RI) lines reveals that these two complementing gene products are a restricting element (R) encoded by the H-2 (MHC) locus on chromosome 17 and a subunit of the T-cell receptor (anti-R) encoded by the Tar alpha-locus on chromosome 14. The order and orientation of gene segments within the Tar alpha-locus has also been established relative to the chromosome 14 marker, Es-10. The existence of two RI strains which are recombinant at chromosome 14 has made it possible to determine that this order is Es-10--v alpha-1--v alpha-2--[C alpha--Np-2]--centromere. The implications of these data for the antigen-specific regulation of immune responsiveness are discussed in terms of the dual recognitive-single receptor model.

Delineation of a defect in T cell receptor beta genes of NZW mice predisposed to autoimmunity

In an attempt to determine whether genes involved in T cell antigen recognition are structurally abnormal and thereby promote murine systemic lupus, we analyzed the structural integrity of the D, J, and C region elements of the T cell receptor alpha and beta chain genes in all major lupus strains and several normal strains. Within the limits of restriction fragment length polymorphism analysis, all strains had an identical genomic organization, except the NZW mice, in which a deletion of the C beta 1-D beta 2-J beta 2 elements was found. Sequence analysis of NZW genomic elements containing this deletion placed its probable origin within the first exon of C beta 1, and extending to a complementary region within the first exon of C beta 2. The significance of this abnormality in the pathogenesis of systemic autoimmune disease remains to be determined.

Murine T-cell receptor mutants with deletions of beta-chain variable region genes

Genomic Southern blots of DNA from eight strains of mice were examined for restriction fragment length polymorphisms in their loci encoding the variable region of the T-cell receptor beta chain (V beta), using 16 different V beta-specific probes. Mouse strains BALB/c, C57BL/6, C3H, and PL were identical, while strains SJL, C57BR, C57L, and SWR shared several polymorphisms with respect to the other four strains. In addition, SJL, C57L, C57BR, and SWR DNAs were missing 50% of the hybridizing bands visualized in BALB/c DNA. A cDNA library from concanavalin A-stimulated SJL spleen blasts was constructed and examined for V beta gene usage. Ten genes were found to account for all V beta-containing clones isolated, including three newly identified V beta genes. All 10 of these genes were found to be present in BALB/c mice. We conclude that SJL, C57L, C57BR, and SWR mice represent V beta deletion mutants of the BALB/c genotype.

Stimulation and expansion of a human T-cell subpopulation by a monoclonal antibody to T-cell receptor molecule

A murine monoclonal antibody (MAb) was obtained that showed unique specificity for the immunizing T-cell line HPB-ALL. This antibody, C37 (an IgG1,K) also reacted with a small (2-5%) population of normal peripheral blood T (PBL-T) cells. These C37-positive (C37+) cells were found in both the T4/Leu3+ and T8/Leu2+ subsets. Like OKT3 antibody, C37 induced T-cell mitogenesis with a peak proliferative response at day 3. In long-term cultures containing irradiated autologous feeder cells and IL-2, C37 antibody caused the selective expansion of C37+ T cells. On HPB-ALL cells C37 induced comodulation of the T3 molecule. C37 precipitated a disulfide-linked dimer characteristic of the T-cell antigen receptor consisting of an alpha-subunit (45-48 kD) and a beta-subunit (38-42 kD) from both C37+ T-cell blasts of a normal individual and HPB-ALL cells that were surface radioiodinated. However, the precipitated molecule isolated from C37 antibody-activated T-cell blasts exhibited a different pI from that isolated from HPB-ALL cells. Our studies indicate that C37 recognizes an epitope on the T-cell receptor molecule that is shared by a subpopulation of human T cells, which raises the possibility that multiple variable-region associated and/or framework-like determinants of the T-cell antigen receptor can be defined serologically and used in functional and molecular studies of T-cell subsets.

Expression of antigen-specific, major histocompatibility complex-restricted receptors by cortical and medullary thymocytes in situ

We have examined the distribution of the antigen-specific, major histocompatibility complex-restricted receptor on mouse thymocytes in situ, using immunohistochemical techniques and the monoclonal antibody KJ16-133. This antibody reacts with the beta chain of the receptors on about 20% of peripheral murine T cells. Of the cortical thymocytes reacting with KJ16-133, cells with only cytoplasmic staining were most frequently observed. Such cytoplasmic staining was not observed in the medulla. Occasional cortical cells had low levels of surface expression, which was almost invariably patched in the region of contact with epithelial cell processes. KJ16-133+ medullary thymocytes had high levels of uniform surface labeling. These results suggest that thymic selection of MHC restriction and/or tolerance may occur in the cortex, where the receptors on maturing thymocytes interact with MHC proteins on epithelial cells.

T-cell receptor beta-chain expression: dependence on relatively few variable region genes

Fifteen independently isolated complementary DNA clones that contain T-cell receptor (TCR) V beta genes were sequenced and found to represent 11 different V beta genes. When compared with known sequences, 14 different V beta genes could be defined from a total of 25 complementary DNA's; 11 clones therefore involved repeated usage of previously identified V beta's. Based on these data, we calculate a maximum likelihood estimate of the number of expressed germline V beta genes to be 18 with an upper 95 percent confidence bound of 30 genes. Southern blot analysis has shown that most of these genes belong to single element subfamilies which show very limited interstrain polymorphism. The TCR beta-chain diversity appears to be generated from a limited V beta gene pool primarily by extensive variability at the variable-diversity-joining (V-D-J) junctional site, with no evidence for the involvement of somatic hypermutation.

A large deletion within the T-cell receptor beta-chain gene complex in New Zealand white mice

The T-cell receptor beta-chain gene complex contains a duplication of D beta, J beta, and C beta gene segments in mice and man. When DNA from many inbred strains of mice was screened an unusual allele of the beta locus was identified in New Zealand White (NZW) mice. This allele is distinguished by the deletion of an 8.8-kilobase segment of DNA containing C beta 1, D beta 2 and the J beta 2 cluster. Despite the fact that all NZW T-cell receptors must be derived from a single set of beta-chain gene segments, this strain has functional T cells and is phenotypically normal. This deletion of T-cell receptor beta-chain segments occurs in a strain known to contribute to lupus-like autoimmune disease.