T cell receptor usage in autoimmune disease

Generation and optimization of off-the-shelf immunotherapeutics targeting TCR-Vβ2+ T cell malignancy

Current treatments for T cell malignancies encounter issues of disease relapse and off-target toxicity. Using T cell receptor (TCR)Vβ2 as a model, here we demonstrate the rapid generation of an off-the-shelf allogeneic chimeric antigen receptor (CAR)-T platform targeting the clone-specific TCR Vβ chain for malignant T cell killing while limiting normal cell destruction. Healthy donor T cells undergo CRISPR-induced TRAC, B2M and CIITA knockout to eliminate T cell-dependent graft-versus-host and host-versus-graft reactivity. Second generation 4-1BB/CD3zeta CAR containing high affinity humanized anti-Vβ scFv is expressed efficiently on donor T cells via both lentivirus and adeno-associated virus transduction with limited detectable pre-existing immunoreactivity. Our optimized CAR-T cells demonstrate specific and persistent killing of Vβ2+ Jurkat cells and Vβ2+ patient derived malignant T cells, in vitro and in vivo, without affecting normal T cells. In parallel, we generate humanized anti-Vβ2 antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC) by Fc-engineering for NK cell ADCC therapy.

The Emerging Roles of Gamma-Delta T Cells in Tissue Inflammation in Experimental Autoimmune Encephalomyelitis

γδ (gamma–delta) T cells, a small population of unconventional T cells, have been found in central nervous system lesions of multiple sclerosis (MS) patients, but their function in disease activity is not clearly understood. Previous studies in experimental autoimmune encephalomyelitis (EAE) were inconsistent in identifying their specific roles in suppressing or promoting disease pathogenesis. Emerging advancements in the biology of γδ T cells especially in the context of their being the major initial producers of IL-17, suggested their crucial role in pathogenesis of EAE. In addition, γδ T cells express high levels of IL-23R and IL-1R, which further enhance their effector functions in the pathogenesis of EAE. Nonetheless, activated heterogeneous γδ T cells display functional dichotomy, which is crucial in determining the outcomes of tissue inflammation in EAE. In this review, we discussed recent advances in understanding the biology of γδ T cells in tissue inflammation as well as their roles in suppressing or promoting the development of EAE.

Clonal T-cell populations are frequent in the skin and blood of patients with systemic sclerosis

BACKGROUND

Pilot studies were suggestive for a role of clonal T cells in the pathogenesis of systemic sclerosis (SSc).

OBJECTIVES

To investigate the presence of clonal T cells in both peripheral blood and skin of a large collection of patients with SSc.

METHODS

Polymerase chain reaction and high-resolution capillary electrophoresis for detecting T-cell clonality were performed in a series of 126 patients with SSc.

RESULTS

Seventy-seven (61%) of 126 patients had clonal T cells in their peripheral blood. In contrast, a clonal T-cell population was present in only four of 29 (14%) age-matched healthy controls (P = 0.03). Older patients were more likely to have clonal T cells than younger patients with SSc (P < 0.0001). Clonal T cells were more commonly detected in the blood of patients with limited cutaneous SSc (48 of 65 patients, 74%) than in those with diffuse cutaneous disease (29 of 61, 48%; P = 0.0002). Lesional skin specimens from 20 of 44 patients (45%) had detectable clonal T-cell populations. There was no correlation between the presence of circulating clonal T cells and lesional clonal T cells, sex, disease duration, extent of skin sclerosis, digital ulcers, organ involvement (e.g. interstitial lung disease, kidney disease, oesophagus involvement), treatment of SSc, or autoantibody profile.

CONCLUSIONS

Many patients with SSc have expanded clonal T cells in their peripheral blood and skin. These clonal T cells could play a critical role in the pathogenesis of SSc, especially in limited cutaneous disease.

T-cell receptor repertoire in healthy Sardinian subjects

The T-cell receptor (TCR) Vbeta gene usage of CD4+ and CD8+ T-cell subpopulations was evaluated by flow cytometric analysis and by CDR3 spectratyping in healthy subjects belonging to Sardinian population, which is ethnically homogeneous and genetically distant from all other Italian and Caucasoid groups. As described in healthy Caucasian subjects, we found a nonrandom Vbeta gene usage and in some Vbeta families a significant skewed reactivity toward CD4+ T cells. Moreover, different subjects showed expansions in some Vbeta subfamilies, mainly in the CD8+ T cells. By CDR3 spectratyping analysis we found a significantly higher degree of skewness in the TCR Vbeta repertoire of CD8+ than in that of CD4+ T cells. The similarity found in the TCR Vbeta gene usage between the population examined and other Caucasoid groups suggest that the shape of the TCR repertoire is more influenced by rearrangement processes than ethnic background. However, genetic polymorphisms may condition the expression levels of some Vbetas, determining the variability of the TCR repertoire between different populations. Finally, the profound perturbations evidenced in the CD8+ T cell subpopulation could be related to a different response to the antigenic stimulation between CD8+ and CD4+ T lymphocytes.

Identification of amplified clonal T cell populations in the blood of patients with chronic graft-versus-host disease: positive correlation with response to photopheresis

Chronic graft-versus-host disease (cGVHD) is a multiorgan disorder with skin manifestations resembling scleroderma. Since photopheresis, a treatment that induces an anticlonotypic immune response, has proven to be effective in both cutaneous T cell lymphomas with circulating clonal T cells and in cGVHD, we have searched for circulating clonal T cell populations in patients with cGVHD, and determined whether T cell clonality in the blood is associated with therapeutic response. We screened blood samples from 27 patients after HLA-matched allogeneic bone marrow transplantation (allo-BMT), 10 without cGVHD and 17 with extensive cGVHD, for clonal T cell receptor gamma (TCR gamma) gene rearrangements using fluorescent-based polymerase chain reaction (PCR) and automated high-resolution capillary electrophoresis. Amplified populations of clonal T cells with unique TCR gamma gene rearrangements were found in six of 10 (60%) allo-BMT patients without cGVHD and 13 of 17 (76.5%) allo-BMT patients with cGVHD (P = 0.41), as compared to none of 10 (0%) healthy controls. Twelve patients with cGVHD were treated by photopheresis, and the presence of amplified populations of clonal T cells was found to be associated with a cutaneous response to photopheresis, as eight of eight (100%) clone-positive vs none of four (0%) clone-negative patients experienced a clinically significant cutaneous response to treatment (P = 0.001). Our findings suggest that patients with cGVHD that have detectable expanded clonal T cell populations in their peripheral blood, may be more likely to respond to treatment by photopheresis.

T cell clonality and the effect of photopheresis in systemic sclerosis and graft versus host disease

Photopheresis, a leukapheresis-based therapy that combines 8-methoxypsoralen (8-MOP) and ultraviolet-A irradiation, has been shown to be an effective treatment for advanced cutaneous T cell lymphoma (CTCL), but also appears to be effective in certain patients with systemic sclerosis (SSc) and chronic graft versus host disease (cGVHD). In CTCL, clinical responsiveness to photopheresis has been shown to be dependent on the presence of detectable circulating clonal T cells in peripheral blood. Herein we review recent work from our group demonstrating that circulating clonal populations of T cells are detectable in a subgroup of patients with SSc and cGVHD. Furthermore, we provide initial evidence that the presence of a T cell clone in such patients may be associated with responsiveness to photopheresis.

Propagation of lewis rat encephalitogenic T cell lines: T-cell-growth-factor is superior to recombinant IL-2

This study was designed to test the process of selecting encephalitogenic T cell lines in the Lewis rat using recombinant human IL-2 (rhIL-2) in comparison to TCGF. The lines were tested for growth, antigen induced proliferation, cytokine production, V-beta 8.2 expression and pathogenicity. We now report that rhIL-2 and TCGF were equally effective in supporting short-term pathogenic T-cell lines with similar proportion of V-beta 8.2 usage. For the maintenance of long term lines, however, TCGF was superior to IL-2. The concentration of rhIL-2 influenced the cultures: 10 units/ml led to more T-cell proliferation than either 2 or 50 units/ml. However, 50 units/ml of IL-2 led to enhanced Th1 polarization. Thus, the type and concentration of growth factors can influence both the propagation of T cells and their phenotype.

Molecular and flow cytometric analysis of the Vbeta repertoire for clonality assessment in mature TCRalphabeta T-cell proliferations

Clonality assessment through Southern blot (SB) analysis of TCRB genes or polymerase chain reaction (PCR) analysis of TCRG genes is important for diagnosing suspect mature T-cell proliferations. Clonality assessment through reverse transcription (RT)-PCR analysis of Vbeta-Cbeta transcripts and flow cytometry with a Vbeta antibody panel covering more than 65% of Vbeta domains was validated using 28 SB-defined clonal T-cell receptor (TCR)alphabeta(+) T-ALL samples and T-cell lines. Next, the diagnostic applicability of the V(beta) RT-PCR and flow cytometric clonality assays was studied in 47 mature T-cell proliferations. Clonal Vbeta-Cbeta RT-PCR products were detected in all 47 samples, whereas single Vbeta domain usage was found in 31 (66%) of 47 patients. The suspect leukemic cell populations in the other 16 patients showed a complete lack of Vbeta monoclonal antibody reactivity that was confirmed by molecular data showing the usage of Vbeta gene segments not covered by the applied Vbeta monoclonal antibodies. Nevertheless, this could be considered indirect evidence for the "clonal" character of these cells. Remarkably, RT-PCR revealed an oligoclonal pattern in addition to dominant Vbeta-Cbeta products and single Vbeta domain expression in many T-LGL proliferations, providing further evidence for the hypothesis raised earlier that T-LGL derive from polyclonal and oligoclonal proliferations of antigen-activated cytotoxic T cells. It is concluded that molecular Vbeta analysis serves to assess clonality in suspect T-cell proliferations. However, the faster and cheaper Vbeta antibody studies can be used as a powerful screening method for the detection of single Vbeta domain expression, followed by molecular studies in patients with more than 20% single Vbeta domain expression or large suspect T-cell populations (more than 50%-60%) without Vbeta reactivity.

Flow cytometric analysis of the Vbeta repertoire in healthy controls

BACKGROUND

Analysis of the T-cell receptor (TCR)-Vbeta repertoire has been used for studying selective T-cell responses in autoimmune disease, alloreactivity in transplantation, and protective immunity against microbial and tumor antigens. For the interpretation of these studies, we need information about the Vbeta repertoire usage in healthy individuals.

METHODS

We analyzed blood T-lymphocyte (sub)populations of 36 healthy controls (age range: from neonates to 86 years) with a carefully selected most complete panel of 22 Vbeta monoclonal antibodies, which together recognized 70-75% of all blood TCRalphabeta(+) T lymphocytes. Subsequently, we developed a six-tube test kit with selected Vbeta antibody combinations for easy and rapid detection of single ("clonal") Vbeta domain usage in large T-cell expansions.

RESULTS

The mean values of the Vbeta repertoire usage were stable during aging in blood TCRalphabeta(+) T lymphocytes as well as in the CD4(+) and CD8(+) T-cell subsets, although the standard deviations increased in the elderly. The increased standard deviations were caused by the occurrence of oligoclonal T-cell expansions in the elderly, mainly consisting of CD8(+) T lymphocytes. The 15 detected T-cell expansions did not reach 40% of total TCRalphabeta(+) T lymphocytes and represented less than 0.4 x 10(9) cells per liter in our study. Vbeta usage of the CD4(+) and CD8(+) subsets was comparable for most tested Vbeta domains, but significant differences (P < 0.01) between the two subsets were found for Vbeta2, Vbeta5.1, Vbeta6.7, Vbeta9.1, and Vbeta22 (higher in CD4(+)), as well as for Vbeta1, Vbeta7.1, Vbeta14, and Vbeta23 (higher in CD8(+)). Finally, single Vbeta domain expression in large T-cell expansions can indeed be detected by the six-tube test kit.

CONCLUSIONS

The results of our study can now be used as reference values in studies on distortions of the Vbeta repertoire in disease states. The six-tube test kit can be used for detection of single Vbeta domain expression in large T-cell expansions (>2.0 x 10(9)/l), which are clinically suspicious of T-cell leukemia.

Biased TCR Repertoire in Infiltrating Lesional T Cells in Human Bancroftian Filariasis

To investigate the hypothesis that T cells recognizing specific Ags localize to the site of disease activity in human bancroftian filariasis, we have compared the repertoire of TCR Vβ gene segments in lesions vs blood in individual patients by RT-PCR ELISA. Vβ14 and Vβ24 were overrepresented (5% greater in tissue compared with PBMCs and/or tissue/PBMC ratios in the highest 5% of all tissue/PBMC ratios for all Vβs for all subjects) in 50% and 40% of study subjects, respectively. Overrepresentation of these two Vβs did not occur in any control subject. In comparing three patient groups, the proportion of individuals meeting at least one criterion for Vβ14 overrepresentation was shown to increase in tandem with our current concepts of disease progression (asymptomatic filariasis = 25%; clinical filariasis with active infection = 60%; clinical filariasis without active infection = 71%). In 6 of the 10 individuals with Vβ14 overrepresentation, Vβ14 represented &gt;20% of the entire lesional Vβ repertoire. All but one of the 20 study subjects had at least one Vβ gene segment that was overrepresented in tissue compared with PBMCs. Only a small number of Vβs, usually three or less, were overrepresented in any single filariasis patient. However, in the same tissue, no differences between patient groups were found when IFN-γ, TNF-α, IL-4, IL-5, and IL-12 mRNA expression were examined. Taken together, these findings suggest that, in principle, in essentially all patients, whether with subclinical or with clinical filariasis, distinct and limited T cell populations are concentrated in affected tissue.

Immunomodulating therapeutic approaches for multiple sclerosis

In this review we delineate the rationale for immunotherapy in multiple sclerosis and describe the various levels at which immune intervention, according to a modern model of the immune system organization, is feasible. Current and future immunosuppressive and immunomodulating therapeutic approaches at the level of antigen presentation and at the lymphocyte and cytokine network levels are discussed.