Rearrangement of the T-cell receptor delta chain gene in T-cell lymphomas with a mature phenotype.

The configuration of the T-cell receptor (TCR) delta chain gene was assessed using restriction fragment analysis and the Southern blot technique in 39 T-cell lymphomas with a mature immunophenotype. The TCR delta gene was rearranged in four lymphomas although the gamma/delta TCR was not expressed in two cases studied. The TCR delta gene was the only TCR gene rearranged in two cases. Each lymphoma with TCR delta gene rearrangement had an aberrant T-cell immunophenotype and three cases were of the large cell anaplastic type. The TCR delta gene was deleted in 22 cases and was in the germline configuration in 13 lymphomas. Deletion of the TCR delta gene was characteristic of mycosis fungoides, adult T-cell leukemia/lymphoma (human T cell leukemia-lymphoma virus positive), and Lennert's lymphoma, and was not identified in angiocentric lymphomas. In eight cases with TCR delta deletion, however, a large number of polyclonal (presumably reactive) T cells were present and, in these lymphomas, the authors could not determine if TCR delta gene deletion occurred in the polyclonal T cells, the neoplastic cells, or both cell populations. The authors conclude that the TCR delta gene is usually deleted in mature T-cell lymphomas, as would be expected in alpha/beta TCR T cells. However, TCR delta gene rearrangement is detectable in approximately 10% of cases. Analysis of this locus may be useful diagnostically, as it occasionally may be the only molecular marker of clonality in mature T-cell lymphomas T-cell receptor delta chain gene rearrangement also is found most often in lymphomas of the large cell anaplastic type.     

T-cell receptor expression in the T-cell malignancies.

Twenty-eight cases with T-cell neoplasms (10 with T-cell acute lymphoblastic leukemia [T-ALL], 10 with T-lymphoblastic lymphoma, and 8 with peripheral T-cell lymphomas) and 2 cases with reactive lymph nodes were immunohistochemically stained with monoclonal antibodies beta F1, delta TCS1, and WT31; beta F1 antibody recognizes the beta-subunit of T-cell receptor (TCR), whereas delta TCS1 and WT31 recognize the delta- and alpha beta-subunits of TCR, respectively. Five cases with T-ALL, four with T-lymphoblastic lymphoma (T-LL), and seven with peripheral T-cell lymphomas were positive for beta F1. None showed positive reactivity for delta TCS1. One case with T-LL and four cases with peripheral T-cell lymphomas were positive for WT31. Of the nine cases positive for beta F1 among T-ALLs and T-LLs, six were also positive for CD1 (OKT6), whereas six of seven positive cases for CD1 were positive for beta F1. The authors therefore suggest that TCR beta is expressed in the immature T-cells just earlier than or around the same stage of differentiation as those expressing CD1. The authors' immuno-electron microscopy study revealed that positive reactivity for beta F1 was localized predominantly in the cytoplasm of the neoplastic cells in the cases with T-ALL, T-LL and peripheral T-cell lymphomas, and in the cytoplasm of the reactive T-cells. However, it was not localized on the surface membrane. In contrast, positive reactivity for WT31 was localized on the surface membrane of the neoplastic and reactive T-cells. Only half of the cases of peripheral T-cell lymphomas showed positive reactivity for WT31. The authors consider that it may not be a very useful antibody for the detection of TCR alpha beta on the T-cell neoplasms using frozen tissue sections.     

Evidence for the early recruitment of T-cell receptor gamma delta+ T cells during rat listeriosis.

We have previously reported that heat-shock protein (hsp) 60-reactive T-cell receptor (TCR)gamma delta+ T cells appear in the peritoneal cavity during the early stage of infection with Listeria monocytogenes in mice. In this study, we examined the kinetics of TCR gamma delta+ T cells during listeriosis in F344 rats by flow cytometry using a V65 monoclonal antibody (mAb) directed to a constant determinant of rat TCR gamma delta chains. TCR gamma delta+ T cells significantly increased in the peritoneal cavity on day 6 and then decreased by day 10 after infection, in parallel with the kinetics of hsp60 expression in the peritoneal macrophages during listeriosis in F344 rats. Most of the early appearing TCR gamma delta+ T cells were of the CD4- CD8 alpha beta+ CD5+ lymphocyte function-associated antigen (LFA)-1 alpha high CD45RC- interleukin-2 receptor (IL-2R) alpha- phenotype, although a significant fraction of the TCR gamma delta+ T cells expressed CD8 alpha only. The increase in TCR gamma delta+ T cells during listeriosis was prominent in F1 (F344 x Lewis) rats but only marginal in Lewis rats, which was correlated with the expression level of hsp 60 in the peritoneal macrophages. The peritoneal TCR gamma delta+ T cells in naive F344 rats appeared to proliferate significantly in response to recombinant hsp 60 (rhsp 60) derived from Mycobacterium bovis bacillus Calmette-Guérin (BCG). These results imply that the early appearance of hsp 60-reactive TCR gamma delta+ T cells during listerial infection can be generalized across species.     

Phenotypic changes and proliferative activity of human gamma delta T cell receptor-bearing cells upon activation.

We first compared the proliferative activity of alpha beta T cell receptor (TCR) (beta F1+) and gamma delta TCR (TCR delta-1+) human T cells after phytohaemagglutinin (PHA) stimulation by using double-colour immunofluorescence staining with Ki67 and anti-BrdU monoclonal antibodies (MoAbs). The dividing activity was higher within the alpha beta TCR cells: after 3 days of culture 69.9 +/- 5.9% of beta F1+ cells expressed Ki67, and 44.8 +/- 4.8% of these cells synthesized DNA as revealed by BrdU incorporation. In contrast, only 18.9 +/- 1.6% and 12.0 +/- 1.2% of TCR delta-1+ cells in the same samples were Ki67+ and BrdU+, respectively. Cells with V delta 1-J delta 1 usage (delta TCS-1+) showed a higher cycling activity than the rest of gamma delta TCR cells: after 3 days of PHA stimulation, 51.1 +/- 18.3% and 18.3 +/- 6.1% of such cells were in cycle and synthesized DNA, respectively. Next, we studied the expression of CD45 isoforms on peripheral blood alpha beta TCR and gamma delta TCR lymphocytes. Within the alpha beta TCR cells, two distinct subpopulations were distinguishable after labelling with SN130 (CD45RA) MoAb: 64.1 +/- 10.2% were bright, and 35.9 +/- 10.2% were dim or negative. Likewise, most TCR delta-1+ cells expressed SN130 (CD45RA): 87.5 +/- 3.0% were bright and 12.5 +/- 3.0% were dim. However, in contrast to alpha beta TCR+ cells, a high proportion (55.6 +/- 4.0%) of gamma delta TCR+ cells also expressed CD45RO molecules. Thus, most resting gamma delta TCR cells showed a pattern of CD45 isoform expression similar but not identical to that of 'memory' alpha beta TCR cells. Within the gamma delta TCR cell population the expression of CD45RO was heterogeneous because only 19.8 +/- 5.9% of cells bearing the V delta 1-J delta 1 form of the receptor (delta TCS-1+) were UCHL1 (CD45RO)+. Therefore, most gamma delta TCR cells with V delta 1-J delta 1 usage showed a CD45 isoform profile resembling that of 'naive' alpha beta TCR cells. These phenotypic features changed upon PHA stimulation: after 5 days of culture the proportion of TCR delta-1+ cells expressing UCHL1 increased to 86.0 +/- 3.1% and a two-fold increase in CD45RO expression was also observed in the delta TCS-1+ subpopulation.     

Lymphocytes bearing the gamma delta T-cell receptor in normal human intestine and celiac disease

Monoclonal antibodies to T-cell receptors were used to investigate the prevalence of the two distinct T-cell subpopulations (TCR alpha beta+ and TCR gamma delta+ cells) in the intestinal mucosa of children with celiac disease (gluten-sensitive enteropathy) as compared with normal intestinal mucosa. TCR gamma delta+ cells were rarely identified in the epithelium of human fetal or normal postnatal intestine and few were present in the lamina propria, whereas the number of distribution of TCR alpha beta+ cells closely resembled that of CD3+ cells. Compared with normal intestine, a significant increase in the number of CD3+, CD8+, TCR alpha beta+, and TCR gamma delta+ intraepithelial lymphocytes was present in celiac disease. Although the mucosal TCR gamma delta+ cells were less numerous than TCR alpha beta+ cells in celiac disease, there was a marked increase in the number of TCR gamma delta+ cells as compared with controls. The ligand recognized by the gamma delta T-cell receptor and the function of these cells have not been determined; however, these findings suggest a possible role for TCR gamma delta+ lymphocytes in mucosal immune responses and tissue injury as seen in celiac disease.     

Hepatosplenic gamma/delta T-cell lymphoma in immunocompromised patients. Report of two cases and review of literature.

We describe 2 male patients in whom hepatosplenic gamma/delta T-cell lymphoma (HSTL) developed 6 and 10 years after renal transplantation. The onset was abrupt with systemic symptoms, cytopenia, and hepatosplenomegaly. The histologic examination of the spleen (case 1), liver, and bone marrow revealed sinusoidal infiltrates of markedly abnormal lymphocytes. The neoplastic cells in these cases were CD2+, CD3+, CD4-, CD5-, CD7+, CD8+, CD16+, CD56+, beta F1-negative, and TIA-1-negative. Both cases displayed clonal rearrangement of the T-cell receptor (TCR) delta gene and the TCR beta gene. The spleen in case 1 was positive for Epstein-Barr virus genome and showed TCR-gamma gene rearrangement by polymerase chain reaction. Isochromosome 7 [i(7)(q10)] was found in each case. Both patients died within 4 months of diagnosis. HSTL has been reported in only 5 renal transplant recipients. HSTL may be relatively more frequent in immunocompromised patients compared with the general population.     

Expression of T-cell receptors TcR1 (gamma/delta) and TcR2 (alpha/beta) in the human intestinal mucosa.

Cryostat sections of normal human adult gastrointestinal mucosae were studied by double-label immunofluorescence with antibodies to CD3, CD4, CD8, CD5 and CD6, in parallel with antibodies beta F1 and TCR delta 1 against beta-chains and delta-chains of the T-cell receptor (TcR) types TcR2 (alpha/beta) and TcR1 (gamma/delta), respectively. Virtually no TcR1+ were found within the lamina propria. In the epithelial compartment, TcR1+ cells were infrequent: in the small bowel, congruent to 2% of T cells were TcR1+. In the colonic epithelium, the percentage of T cells expressing gamma/delta-chains was higher, with a mean value approximating 15-20%, although this apparently large percentage increase compared with small bowel reflects in part a much lower density of colonic IEL, as absolute numbers of TCR delta 1+ cells were comparable. Of the TcR1+ population, about half were CD4- CD8-, 'double negatives' and the remainder were CD8+. TcR1+ cells were also CD5- CD6-, irrespective of expression of CD8. No CD4+ cells expressing TcR1 were observed: essentially all CD4+ cells were beta F1+, with some variability of labelling intensity. Approximately 30-50% of the CD8+ subset expressed the beta F1 antigen strongly. However, in the remaining TcR1- CD8+ cells, which were all of the CD5- CD6- phenotype, expression of the beta F1 antigen was only detectable when streptavidin and biotin conjugates were used for amplification of labelling. Thus, the CD8+ CD5- subset, a prominent population of the epithelial compartment of the small bowel, was either TcR2dull in the majority or TcR1+ in a minority. Our data imply that gamma/delta TcR1 cells may be actively excluded from intestinal lamina propria, and that any preferential localization that does occur is limited and is rather a feature of the colonic mucosa, rather than the small bowel.     

Clonally expanded CD3+, CD4-, CD8- cells bearing the alpha/beta or the gamma/delta T-cell receptor in patients with the lymphoproliferative disease of granular lymphocytes.

Among 60 retrospectively assessed patients with the lymphoproliferative disease of granular lymphocytes (LDGL), lymphocytes from only 2 patients had the CD3+, CD4-, CD8- phenotype, rarely observed in normal peripheral blood lymphocytes (about 3%). In this paper we report a detailed study of lymphocytes isolated from these two patients. The cells from patients 1 had the CD3+, CD4-, CD8-, WT31-, beta F1-, TCR delta 1+, Ti gamma A-, BB3+, CD7+, CD16-, CD57+ phenotype, while cells from patient 2 had a phenotype even more rarely observed on normal lymphocytes: CD3+, CD4-, CD8-, WT31+, beta F1+, TCR delta 1-, CD7+, CD16-, CD57+. Thus, in only the first case the cells expressed the gamma/delta T-cell receptor (TCR) on the membrane, while the cells from the second case had the alpha/beta TCR. Genetic studies showed that in case 1 the TCR gamma gene was rearranged and the beta chain gene configuration was germline; the TCR mRNA was of normal size for the gamma chain, while that of the beta chain was truncated. Case 2 had the beta and the gamma genes of the TCR rearranged, but only the alpha and beta mRNA were expressed. In agreement with these findings, the delta chain gene of the TCR was rearranged in case 1 and was deleted in case 2. Cytotoxic activity was absent in cells from case 1 and low in case 2; in the latter, the lytic activity could be up-regulated following incubation with IL-2 or an anti-CD3 monoclonal antibody. Our study indicates that CD3+, CD4-, CD8- lymphocytes are rarely expanded in patients with LDGL. The detection of a lymphoproliferative disease of a CD3+, CD4-, CD8-, alpha/beta + cell may contribute to a better characterization of this novel lymphocytic subpopulation.     

Mouse T lymphocytes that express a gamma delta T-cell antigen receptor contribute to resistance to Salmonella infection in vivo.

Mice depleted of lymphocytes expressing the alpha beta or the gamma delta T-cell receptor for antigen (TCR) by antibody treatment were infected orally with Salmonella enteritidis. In both groups of treated mice, the 50% lethal dose decreased, suggesting that both the alpha beta TCR+ and the gamma delta TCR+ subsets contribute to resistance to oral infection. These data provide further evidence for the contribution of gamma delta T cells in the response to bacterial infections.     

Immunophenotyping and gene rearrangement analysis provide additional criteria to differentiate between cutaneous T-cell lymphomas and pseudo-T-cell lymphomas.

Differentiation between cutaneous pseudo-T-cell lymphomas and cutaneous T-cell lymphomas (CTCLs) may be extremely difficult. In this study, it was investigated whether demonstration of an aberrant phenotype and detection of clonal T-cell receptor gamma (TCR gamma) gene rearrangements can be used as additional differential diagnostic criteria. Immunohistochemical studies and TCR gamma gene rearrangement analysis using a polymerase chain reaction with primers specific for V gamma 1-8 and V gamma 9 gene segments in combination with denaturing gradient gel electrophoresis (PCR/ DGGE) were performed on frozen material of 11 pseudo-T-cell lymphomas and 17 CTCLs, including 9 cases of mycosis fungoides (MF) and 8 pleomorphic CTCLs. Clonal TCR gamma gene rearrangements were found in 66% of patch/plaque-stage MF and 100% of tumor-stage MF and pleomorphic CTCL, but not in any of 10 pseudo-T-cell lymphomas studied. Aberrant expression of CD2, CD3, and/or CD5 antigens was noted in 3 of 6 (50%) cases of patch/plaque-stage MF, all three cases of tumor-stage MF, and 5 of 8 (62%) pleomorphic CTCLs, but not in any of the 11 pseudo-T-cell lymphomas. Moreover, in pseudo-T-cell lymphomas exhibiting a nodular or diffuse growth pattern, a considerable admixture with reactive CD8+ T cells (15 to 60%), B cells (up to 20%), and macrophages was a characteristic finding. In conclusion, the results of this study suggest that demonstration of clonal TCR gene rearrangements and an aberrant phenotype, as well as demonstration of many admixed CD8+ T cells and B cells can be considered as useful additional criteria in the differentiation between pseudo-T-cell lymphomas and CTCLs.     

T-cell receptor usage of interleukin-2-responsive peripheral gamma delta T cells.

The majority of human peripheral gamma delta T cells express the V gamma 9 gene in combination with the V delta 2 gene. The diversity of this subset of gamma delta T cells is limited by a preferential usage of the J gamma P gene segment and a highly distinctive junctional motif of the T-cell receptor (TCR) delta chain. We and others have observed that peripheral blood derived V gamma 9+V delta 2+ gamma delta T cells of healthy individuals are activated after stimulation with interleukin-2 (IL-2) in vitro, but only a small percentage of gamma delta T cells subsequently proliferates. To assess whether the proliferating, IL-2-responsive gamma delta T cells represent a selective group of T cells, we have analysed TCR junctional features of IL-2-responsive gamma delta T cells. Out of 30 individuals studied, nine were identified as IL-2-responders and three as IL-2-hyperresponders. The TCR V(D)J gene usage from IL-2 stimulated peripheral blood lymphocytes of these IL-2-(hyper)responsive individuals was analysed. The results showed that in most individuals gamma delta T cells polyclonally expanded after stimulation with IL-2. In two IL-2-hyperresponder individuals, however, a monoclonal expansion of a particular V gamma 9+V delta 2+ gamma delta T cell was found. In one of these individuals, this V gamma 9+V delta 2+ T-cell clone expressed a very rare gamma delta TCR type because of the presence of an Ala within the junctional region at a conserved position relative to V delta framework residues (delta 97), which is very infrequently used by peripheral blood V gamma 9+V delta 2+ cells. This particular clonotype could also be detected in unstimulated PBL samples taken from that individual, and made up for 30% of the total peripheral gamma delta T-cell pool. These data indicate that in general IL-2-responsive V gamma 9+V delta 2+ gamma delta T cells represent a polyclonal population, reflecting in vivo stimulation with multiple antigens or superantigens. In contrast, monoclonal expansions of gamma delta T cells after stimulation with IL-2 can also occur, which may be related to an in vivo stimulation by one particular antigen, rendering this gamma delta T-cell type dominant in the peripheral blood.     

IL-4 is able to reverse the CD2-mediated negative apoptotic signal to CD4-CD8- alpha beta and/or gamma delta T lymphocytes.

Activation of immature thymocytes or transformed T lymphocytes via T-cell receptor (TCR)/CD3 signalling can induce programmed cell death (apoptosis). Recent data indicate that anti-CD3/TCR monoclonal antibodies (mAb) also trigger apoptosis in activated (but not resting) mature peripheral blood T lymphocytes. Here we report that triggering of resting CD4-CD8-TCR alpha beta+ and/or TCR gamma delta+ via the alternative CD2-dependent activation pathway is able to induce programmed cell death. A pair of mitogenic anti-CD2 mAb provoked a dramatic rise in [Ca2+]i that was almost entirely sustained by extracellular fluxes, and the inhibition of membrane [Ca2+/Mg2+] ATPase. The resulting endonuclease activation was able to induce DNA fragmentation, as revealed by propidium iodide staining and gel electrophoresis. Induction of apoptosis was prevented by the presence of interleukin-4 (IL-4) as well as by endonuclease inactivation with 100 microM ZnCl2, but enhanced by the contemporary block of protein kinase C. Thus it seems that in resting T lymphocytes the strong calcium signal delivered by the alternative CD2 activation pathway may act as a negative apoptotic signal in both alpha beta and gamma delta T cells with low (non-major histocompatibility complex restricted) antigenic affinity, so limiting the extension of polyclonal T-cell growth.     

Discordant expression of CD3 and T-cell receptor beta-chain antigens in T-lineage lymphomas.

Using an immunoperoxidase technique that identifies both surface and cytoplasmic antigen expression, the authors examined 28 benign reactive lymphorproliferative lesions and 55 T-lineage lymphomas for reactivity with CD3 (Leu-4; T-cell receptor-associated antigen) and beta F1 antibodies, the latter recognizing nonpolymorphic determinants on T-cell receptor beta chains. Consistent with previous observations that these two antigens are co-expressed on the vast majority of thymocytes, peripheral blood T cells and tonsillar T cells, all 28 reactive lymphoproliferations showed essentially identical patterns of CD3 and beta F1 expression. In contrast, only 29 of 55 T-lineage lymphomas displayed coexpression of these antigens. Among 33 peripheral T-cell lymphomas, 11 cases showed CD3/beta F1 discordance (7 CD3+/beta F1-; 4 CD3-/beta F1+), and 5 showed absence of both these antigens. Nine of 22 T-lymphoblastic lymphomas showed CD3/beta F1 discordance (all CD3+/beta F1-), and 1 case was CD3-/beta F1-. These patterns of CD3/beta F1 expression, along with the patterns of CD2, CD4, CD5, CD7, and CD8 antigen expression in these neoplasms, indicate that T-cell lymphomas can manifest phenotypes not apparently reflective of normal T populations and suggest the presence of abnormal gene expression in these malignancies. The existence of aberrant phenotypes in T-cell neoplasia suggests caution in interpretation of investigations using T-lineage malignancies as models of normal T-cell biology. Finally, the identification of phenotypic abnormalities in T-lineage populations can be of great diagnostic usefulness in the delineation of benign versus malignant T-cell proliferations.     

Polymyositis mediated by T lymphocytes that express the gamma/delta receptor.

BACKGROUND. The invasion and destruction of nonnecrotic muscle fibers by CD8+ cytotoxic T cells is considered a hallmark of polymyositis. In the cases of polymyositis reported so far, the autoinvasive CD8+ T cells expressed the common form of T-cell receptor for the recognition of antigen, the so-called alpha/beta T-cell receptor. We describe a 69-year-old man with polymyositis mediated by CD4-, CD8- T cells expressing the recently discovered, uncommon gamma/delta T-cell receptor. METHODS. We used immunofluorescence or immunoperoxidase techniques to study frozen sections of muscle from our patient, who had mild weakness of cervical and proximal limb muscles, and from control patients with polymyositis, inclusion-body myositis, dermatomyositis, or granulomatous myopathy with monoclonal antibodies against T-cell-related antigens (CD2, CD3, CD4, CD8, and gamma/delta T-cell receptor), B cells (CD22), major histocompatibility complex (MHC) and MHC-related antigens (MHC Class I, CD1a, CD1b, and CD1c), and the 65-kd heat-shock protein. The membrane contacts between the autoinvasive cells and the sarcolemma were investigated by electron microscopy. RESULTS. In the patient described here, but not in 28 others with inflammatory myopathies, myriad gamma/delta T cells surrounded and invaded nonnecrotic muscle fibers. All muscle fibers were highly reactive for MHC Class I antigen and the 65-kd heat-shock protein. Treatment with prednisone improved the clinical and histologic findings. CONCLUSIONS. Polymyositis can be mediated by gamma/delta T cells. This new form of polymyositis appears to be highly responsive to steroids.     

Lymphocytes infiltrating normal human lung and lung carcinomas rarely express gamma delta T cell antigen receptors.

It has been suggested that T lymphocytes expressing gamma delta T cell receptors (TCR) could play an important role in the defence of epithelia against infection and neoplastic transformation, but the potential for gamma delta T lymphocytes to serve these functions in human respiratory epithelium has received little attention. In this study, we used immunohistochemical techniques and specific monoclonal antibodies to characterize the number and distribution of T lymphocytes expressing alpha beta and gamma delta TCR in normal human lung and in lung carcinomas. T lymphocytes present in normal bronchi and alveolar parenchyma were predominantly of the alpha beta TCR phenotype, whereas gamma delta T lymphocytes represented only 1.1 +/- 0.7% and 1.3 +/- 0.5% of total CD3+ lymphocytes respectively. An important lymphocytic infiltration was noted in the stroma of all primary lung carcinomas examined, and some T lymphocytes were also present infiltrating between tumour cells. These T lymphocytes were almost entirely alpha beta T cells and only rare gamma delta T cells were found, regardless of the histologic type of carcinoma (0.8 +/- 0.1% of CD3+ T cells). This study demonstrates that T cells present in normal bronchi and lung parenchyma and those infiltrating primary lung carcinomas express predominantly alpha beta TCR. These findings do not support the conclusion that gamma delta T lymphocytes play an important role either in the defence of human lung epithelia or in immune responses directed against primary lung carcinomas.     

T cells expressing gamma delta chain receptors in rheumatoid arthritis

Whereas the majority of T cells use alpha and beta chains to form their T-cell receptor, a small minority of T cells, which do not express the CD4 or CD8 surface markers, use other chains termed gamma and delta to form their receptor. Flow cytometry was performed on cells isolated from the blood and synovial joints of patients with rheumatoid arthritis. Monoclonals which recognise the gamma and delta chains were used to compare the proportion of TCR gamma delta cells in these sites. Approximately half the patients had more TCR gamma delta in the joints than in their blood and one newly diagnosed patient had high numbers of TCR gamma delta cells in both blood and joints. In this preliminary study it is not possible to evaluate the role of these cells in the disease process, but it is of interest that in some RA patients there is an overabundance of both T cells that arise early in ontogeny (TCR gamma delta cells) and B cells that arise early in ontogeny, the CD5 B cell.     

BMA031, a monoclonal antibody suited to identify the T-cell receptor alpha beta/CD3 complex on viable human T lymphocytes in normal and disease states.

Two types of T lymphocytes can be discriminated on the basis of expression of either the classical T-cell receptor (TCR) alpha beta or the more recently identified TCR gamma delta. Whereas TCR alpha beta + lymphocytes are known to respond to recognition of antigen in the context of major histocompatibility complex molecules by proliferation, lymphokine secretion, and/or cytotoxicity, the potential ligand specificities and functions of TCR gamma delta + cells have not been completely unraveled. Antibodies specific for either receptor type are important tools to elucidate the role TCR gamma delta + cells play in the immune system. They can be used to quantify TCR gamma delta + cells and TCR alpha beta + cells in normal and disease states, to isolate both T-cell subsets, and to perform in vitro functional assays. Only few antibodies reactive with common determinants on either TCR alpha beta or TCR gamma delta are available. Generally, the monoclonal antibody (mAb) WT31 is used for definition of viable human TCR alpha beta + cells. However, WT31 has recently been shown to cross-react with TCR gamma delta. We describe an mAb, BMA031, that combines the unique features of reactivity with intact viable cells and true specificity for a common determinant on the TCR alpha beta/CD3 complex. Its performance in immunofluorescence staining and immunochemistry has been compared with that of WT31 and anti-TCR gamma delta mAbs, using TCR alpha beta and TCR gamma delta expressing cells isolated from blood and bone marrow of healthy individuals and immunodeficient patients.     

Absence of clonal beta and gamma T-cell receptor gene rearrangements in a subset of peripheral T-cell lymphomas.

The authors describe a set of seven peripheral T-cell lymphomas that lack detectable rearrangements of T-cell receptor (TCR) genes. All cases showed antigenic profiles consistent with T-cell lymphoma, including expression of Leu-5 (CD2) antigen. However, few other T-lineage markers were found, and none of the cases tested (6 of 7) bound antibody recognizing the constant region of the beta TCR protein. Each case showed exclusively germline configurations of DNA for the beta TCR genes in Southern blot analyses with the use of several different combinations of restriction enzymes and DNA hybridization probes. One case contained clonal rearrangements of the gamma TCR gene and of the immunoglobulin heavy chain gene. Our results suggest that certain cases of peripheral T-cell lymphoma may lack rearrangements of TCR genes--particularly those cases expressing restricted numbers of T-lineage antigens. In view of these findings, failure to detect rearrangements of TCR genes by Southern blot analyses is not necessarily inconsistent with malignant lymphocytic proliferations in T-lineage neoplasia.