Variables affecting the T cell receptor V beta repertoire heterogeneity of T cells infiltrating human renal allografts

Matching T-cell receptors identified in renal biopsies and urine at the time of acute rejection in pediatric renal transplant patients

Urinary monitoring of kidney allograft function has been used for many years. More recently, molecular identification of cytotoxic T-cell products has been used as a diagnostic tool in acute rejection. Monitoring of T-cell infiltrates by analysis of the T-cell receptor (TcR) gene usage has been performed on biopsies with acute and chronic rejection, but not on urine samples. The aim of this study was to identify and compare TRBV gene usage assessing the CDR3 (Complementarity Determining Region 3) length distribution and sequence in urine and biopsies of pediatric renal allograft patients at the time of acute rejection and compare them with peripheral blood. We studied four pediatric renal transplant recipients with acute cellular rejection. We identified restricted and matched TRBV CDR3 spectratypes with overexpressed TRBV families and show identical, clonally expanded TRBV CDR3 sequences in all four patients present in the urine and renal allograft. We demonstrate that urinary monitoring can detect graft-infiltrating lymphocytes in acute rejection and may have a role in the monitoring of renal transplants.

Skew in T-cell receptor usage and clonal T-cell expansion in patients with chronic rejection of transplanted kidneys

BACKGROUND

It is not known whether alloreactive T cells are involved in chronic rejection of transplanted kidneys. The aim of the present study was to determine the involvement of T cells in the chronic graft rejection.

METHODS

T-cell receptor (TCR) variable region alpha-chain and TCR variable region beta-chain repertoires were analyzed in peripheral blood mononuclear cells. T-cell clonalities were analyzed by complementarity-determining region 3 size spectratyping.

RESULTS

A significant increase in the frequencies of one or more TCR variable region alpha-chain and TCR variable region beta-chain segments was detected in 13 and 15 of the 24 kidney transplant recipients, respectively. The extent of the skew in the TCR usage was correlated with the levels of clonal T-cell expansion, indicating that the clonally expanding T cells were responsible for the skew in the TCR usage. The levels of the skew in the TCR usage and clonal T-cell expansion were significantly greater in the recipients with a graft failure than in those with a stable graft function ( P=0.0081 and P=0.012, respectively). These results indicate that the clonally expanding T cells in the periphery may be related to graft rejection. The percent increase in the serum creatinine levels, which reflected the deterioration of the kidney functions, was significantly higher in the recipients who showed high levels of clonal T-cell expansion than in those who did not ( P=0.021).

CONCLUSIONS

The results demonstrate that clonal T-cell expansion in the periphery has a negative impact on the long-term graft functions, and that analysis of the clonal T-cell expansion in peripheral blood mononuclear cells provide significant information on the fate of the transplanted kidney.

Modulation of the T cell receptor beta chain repertoire after heart transplantation

BACKGROUND

In a previous study it was shown that pre-transplant blood transfusion was associated with a better clinical outcome after heart transplantation (HTx). In this study the effect of heart transplantation (HTx) on the T cell receptor V beta chain (TCRVbeta) repertoire was investigated. Therefore, we analyzed the TCRVbeta repertoire of patients after HTx to see whether a correlation with clinical outcome could be observed.

METHODS

Patients were analyzed at four different time points: pre-HTx, less than 1 month post-Htx, between 1 month and 2.5 month post-Htx and more than 2.5 months post-HTx. CD4+ and CD8+ T cells were purified from patient peripheral blood mononuclear cells (PBMC). TCR beta chain usage was analyzed semiquantitatively by Southern blot analysis.

RESULTS

HTx affected the TCRVbeta repertoire in both the CD4+ and CD8+ T cell compartments in all patients. Changes in the TCRVbeta repertoire were most pronounced within the CD8+ T cell subset. Interestingly, one patient showed modulation in TCRVbeta chain usage predominantly in the CD4+ T cell compartment.

CONCLUSIONS

Modulation of TCRVbeta chain usage was detected in all patients analyzed. No clear-cut relation was observed between TCRVbeta modulation after transplantation and clinical outcome. In some cases modulations appeared to concur with observed immunological events (clinically and/or in-vitro).

Highly altered V beta repertoire of T cells infiltrating long-term rejected kidney allografts

Chronic rejection represents a major cause of long-term kidney graft loss. T cells that are predominant in long-term rejected kidney allografts (35 +/- 10% of area infiltrate) may thus be instrumental in this phenomenon, which is likely to be dependent on the indirect pathway of allorecognition only. We have analyzed the variations in T cell repertoire usage of the V beta chain at the complementary determining region 3 (CDR3) level in 18 human kidney grafts lost due to chronic rejection. We observed a strongly biased intragraft TCR V beta usage for the majority of V beta families and also a very high percentage (55%) of V beta families exhibiting common and oligoclonal V beta-C beta rearrangements in the grafts of patients with chronic rejection associated with superimposed histologically acute lesions. Furthermore, V beta 8 and V beta 23 families exhibited common and oligoclonal V beta-J beta rearrangements in 4 of 18 patients (22%). Several CDR3 amino acid sequences were found for the common and oligoclonal V beta 8-J beta 1.4 rearrangement. Quantitative PCR showed that biased V beta transcripts were also overexpressed in chronically rejected kidneys with superimposed acute lesions. In contrast, T lymphocytes infiltrating rejected allografts with chronic rejection only showed an unaltered Gaussian-type CDR3 length distribution. This pattern suggests that late graft failure associated with histological lesions restricted to Banff-defined chronic rejection does not involve T cell-mediated injury. Thus, our observation suggests that a limited number of determinants stimulates the recipient immune system in long-term allograft failure. The possibility of a local response against viral or parenchymatous cell-derived determinants is discussed.

T cell receptor repertoire usage in allotransplantation: an overview

Lymphocytes express antigen receptors that allow the immune system to specifically recognize antigens. In transplantation, T cells play a critical role in the rejection process, and different protocols inhibiting T cell-mediated alloreactivity efficiently achieve prolongation of allograft survival. T cells can interact with alloantigens by two ways, either by the "indirect" pathway that correspond to the physiological mechanism of T cell immune recognition, or through the "direct" pathway where they recognize alloantigens directly on the surface of donor cells. If some T cells are specifically activated in allorecognition, one should be able to indirectly detect this "selection" by analyzing the T cell receptor usage that could be biased and reflect the preferential amplification of alloreactive lymphocyte subsets. Nevertheless compared with disease states such as cancer or autoimmunity the T cell receptor repertoire is still largely uncharacterized. We review the current results available on T cell repertoire usage in transplantation studies involving humans or various animal models. The T cell receptor repertoire involved in transplantation (restricted or unrestricted) and the features potentially common to alloimmune responses will be discussed.

T-cell receptor variable gene analysis of renal allograft-infiltrating cells in biopsy specimens using a nonradioisotopic micromethod

BACKGROUND

A sensitive micromethod for T-cell receptor (TCR) analysis is needed for clonality analysis of renal allograft-infiltrating T cells (RAITs) obtained by needle biopsy.

METHODS

TCR cDNA was amplified by the anchored polymerase chain reaction and was hybridized with 28 different TCR beta variable (TCRBV) genes fixed on nylon membranes, and the percentage of each TCRBV gene was measured spectrophotometrically.

RESULTS

The specificity and linearity of the hybridization technique and the constancy of the TCRBV percentages over a wide range of sample amounts were demonstrated by control experiments. Analysis of RAITs of biopsy specimens from four patients showed broad or skewed TCRBV usage, indicating the presence of polyclonal and oligoclonal RAIT populations, respectively. In one patient who received OKT3 immunosuppressive treatment, the TCRBV skewness was dramatically reduced after the treatment.

CONCLUSION

We have established a powerful method for analyzing RAIT clonality, which is especially useful for monitoring RAIT dynamics after immunosuppression therapy.

Graft-infiltrating cells in rats receiving orthotopic semiallogeneic small intestine transplantation with portal or systemic venous drainage

The effect of alterations in venous drainage, from either ivc to portal vein (pv), along with peritransplant systemic (ivc) or portal (pv) venous alloimmunization with irradiated semiallogenic cells, on cell subset recovery in lymphoid organs of Lewis rats receiving orthoptic small bowel allografts (from LewisXBrown Norway) F1, LBNF1) was examined. Combined portal, venous drainage and alloimmunization has been reported to increase graft/recipient survival in this model. FACS analysis using monoclonal antibodies specific for different lymphocyte subsets was performed on cell suspensions of peripheral (P) and mesenteric (M) lymph node (LN), small bowel intraepithelial lymphocytes (SBIEL), and Peyer's patch (PP) lymphocytes on days 2 and 8 posttransplantation. Donor cell contributions to these cellular analyses were estimated by comparison of FACS staining with polyclonal anti-Lewis or Lewis anti-LBNF1 antibodies. Control animals received syngeneic grafts. In both syngeneic and semi-allogenic transplants with pv or ivc drainage there was no consistent difference in cell subsets from in PLN compared with those of control nongrafted rats. Approximately 50% to 60% of these cells were alphabetaTcR+ with a CD4+/CD8+ ratio of 3-4:1 and a (CD4++CD8+)/alphabetaTcR+ ratio of 1:1. Some 5% to 12% ED3+ cells were also present. In IEL, MLN, and PP by contrast, there were significant differences in cells recovered from rats with ivc vs. pv drainage of grafts. The most striking changes reflected a decreased CD4+/CD8+ and alphabetaTcR+gammadeltaTcR+ cells in these tissues in rats predestined to show prolongation of allograft survival (ivc vs. pv injected IEL CD4/CD8+ ratios and alphabetaTcR+gammadeltaTcR+ ratios 1.0, 0.7 and 5.0, 1.0, respectively. These data are consistent with a proposed role for such gammadeltaTcR+ cells in the local regulation of graft rejection.

T-cell receptor usage in alloreactivity against HLA-B*2703 reveals significant conservation of the antigenic structure of B*2705

B*2703 is an exceptional HLA-B27 molecule in that it differs from the most common B*2705 subtype by a unique amino acid change (His59) altering N-terminal peptide anchorage. To assess how this unusual feature affects the antigenic structure of HLA-B27, TCR usage by alloreactive CTL raised against B*2703 from two individuals was analyzed. Only few CTL recognized B*2703 from two individuals was analyzed. Only few CTL recognized B*2703 but nor ot at a lower level B*2705. Limited heterogeneity of these CTL was revealed by: 1) identity of TCR in two pairs of such CTL clones, 2) identity of beta chains, paired to distinct alpha chains, in two clonotypes, and 3) almost identical fine specificity of these two clonotypes with site-specific HLA-B27 mutants. These results indicate that B*2703 "private" epitopes are rare. TCR usage among anti-B*2703 CTL was analogous as in anti-B*2705 responses in the predominant and donor-independent usage of V beta segments from homology subgroup 4, more moderate and donor-dependent V alpha skewing, N+D beta diversity limited by motifs shared among clonotypes, and restricted J alpha heterogeneity. Homology of N+D beta motifs and J alpha segments of anti-B*2703 with anti-B*2705 TCR suggested significant sharing of peptide-associated epitopes between both subtypes. The results indicate that allospecific TCR are recruited by B*2703 following similar rules as in the anti-B*2705 response, and suggest that the B*2703 change keeps unaltered much of the antigenic structure of the molecule relative to B*2705. Therefore, most of the peptides bound to B*2703 should be the same and keep a similar conformation as in B*2705.

T cells receptor beta-chain repertoires are nonrandomly selected in responses to HLA-DR1

T cell receptor (TCR) beta-chain usage by HLA-DR1 alloreactive T cell lines was examined to determine whether common TCR gene segments were used preferentially. We have demonstrated previously that a DR1-specific, human renal allograft-derived T cell line and replicate, anti-DR1 mixed lymphocyte reactions (MLR), established from an unrelated responder/stimulator pair, were selected for T cells expressing V beta 8. In this report V beta 8+ beta-chains from these T cell lines were sequenced to assess clonality and determine the contribution made by the beta-chain junctional regions. All 11 V beta 8+ cDNA clones sequenced from the allograft-derived T cell lines used J beta 2.7 and C beta 2 and had identical junctions, indicating the presence of a predominant V beta 8+ clone. All seven V beta 8+ sequences from the first anti-DR1 MLR and eight of the nine fron the second also used J beta 2.7 and C beta 2 were identical to one another, indicating that a common V beta 8+ clone was selected in these replicate cultures. The sequences of the predominant V beta 8+ beta-chains from the allograft-derived T-cell line and the MLR differed by only 10 nucleotides and four amino acids at the VDJ beta junction. To determine the reproducibility of TCR V beta selection in responses to DR1, additional MLR were established by pairing three different DR1+ stimulators with the same responder. The TCR repertoires of the resulting DR1-specific cell lines were examined. A preference was seen for utilization for certain homologous TCR V beta segments. The data suggest that particular TCR V beta or V beta/J beta combinations may be selected in alloresponses as evidenced either utilization of highly similar beta-chains or homologous V beta segments.

T cell receptor (TCR) repertoire in alloimmune responses

A large number of alloantigenic determinants could be generated by both the direct and indirect alloantigen presentation pathways. Hence, a heterogeneous population of T cells expressing a wide variety of receptors would be expected to respond to this diverse array of alloantigenic determinants. However, T cells expressing highly restricted T cell receptor (TCR) variable genes have been reported in a variety of alloimmune responses. A similar phenomenon has been observed in a wide variety of other immune responses, from those induced by superantigens, to very specific responses induced by a single peptide presented by a single MHC molecule. Given this scenario, the limited number of T cell clones which dominate an allograft rejection response, or for that matter an autoimmune response or a tumor specific response, could be therapeutically targeted by virtue of the selected TCR expression.

T cell receptor diversity in alloreactive responses against HLA-B27 (B*2705) is limited by multiple-level restrictions in both alpha and beta chains

The T cell receptors (TCR) in HLA-B27 (B*2705) alloreactivity were analyzed in cytotoxic T lymphocytes (CTL) from two individuals. Non-random usage was found in V beta, N+D beta, V alpha, and J alpha, but not in J beta segments or N alpha-regions. V beta segments from homology subgroup 4 were predominant and not associated to a particular donor or fine specificity, suggesting involvement in recognizing the HLA-B27 molecule. In contrast, preferential V alpha usage was associated with particular individuals and fine specificities, indicating distinct V beta and V alpha recruitment and contribution to allorecognition. Recurrent N+D beta motifs and J alpha segments, even from different donors, limited junctional diversity, suggesting that CDR3 usage was determined by the alloantigenic epitope independently of individuals. TCR were selected differently at various levels, as indicated by the following findings. Four clonotypes with similar fine specificity had identical beta and unrelated alpha chains. Similar alpha were associated with unrelated beta chains, and vice versa. CTL using V beta subgroup 4 did not globally show concomitant predominance of other TCR elements. V alpha 7, one of the preferred V alpha segments, was always associated with V beta subgroups other than 4. Sometimes, a TCR showed homology in elements of one chain to a second TCR or group of TCR, and to another in the other chain. These results are best explained by differential selection of TCR elements by different epitopes, providing a key to the inner structure of allospecific TCR repertoires.