Homing Receptor α4β7 Integrin Expression Predicts Digestive Tract Involvement in Mantle Cell Lymphoma

Appropriate staging and evaluation of residual disease is critical to improving the treatment of patients with lymphoma. The specific expression of homing receptors may determine the preferential dissemination pattern of tumoral cells. We investigated the expression of the mucosal homing receptor α4β7 on tumoral cells from peripheral lymph node in patients with newly diagnosed mantle cell lymphoma (MCL) to check whether it is associated with gastrointestinal involvement. Expression of the α4β1 integrin and the peripheral lymph node addressin CD62L were also examined. Thirteen MCL patients presenting with peripheral lymphadenopathy were studied. Expression of the mucosal homing receptor integrin α4β7 by peripheral lymph node lymphoma cells was found to be frequent (5/13) and associated with gastrointestinal involvement (5/7). In contrast, lymphoma cells from patients without gastrointestinal involvement did not express α4β7 (6/6) (P = 0.03). These data suggest that α4β7 integrin is expressed by a subset of MCLs and that its expression may predict digestive tract involvement in MCL, furnishing a basis for recognizing two distinct clinical and phenotypic forms, ie, “digestive homing (or digestive primitive)” versus “peripheral” MCL. Further studies on more patients will be needed to understand the impact of biological differences on the prognosis of these two clinical forms.     

A bias in the αβ T cell receptor variable region gene usage in Takayasu's arteritis

Takayasu's arteritis (TA) is a chronic large vessel vasculitis with a predilection for the aortic arch and its branches. T lymphocytes may be important in the pathogenesis, as they have been found to infiltrate the vascular lesions. To elucidate further the role of T cells in the disease, we studied circulating CD4⁺ and CD8⁺ T cells, expression of the activation marker (HLA-DR), marker for naive (CD45RA) and primed (CD45RO) cells and the different variable α/β (AV/BV) gene segments on them. The TCR AV/BV repertoire was studied using a panel of 15 T cell receptor (TCR) V-specific MoAbs by flow cytometry in 18 patients and 23 age- and sex-matched controls. Patients had a higher percentage of AV12S1 (P< 0.05), BV6S7 (P< 0.05) and BV9 (P< 0.001)-bearing CD4⁺ cells. Patients also had a higher frequency of expansions, i.e. of T cell populations with an abnormally high TCR AV/BV gene usage. In patients' CD4⁺ subset of cells, there were 22 expansions out of 231 analyses (9.5%), whereas in controls, four were expanded out of 310 analyses (1%) (P< 0.001). For CD8⁺ cells, the frequency of expansions was 32 in 231 analyses (14%) in patients and nine out of 304 analyses in controls (3%) (P< 0.01). In addition, there was a correlation between CD4⁺ expansions and disease activity; nine out of 10 patients with active disease in comparison with two out of eight patients with inactive disease (P< 0.01) had an expansion. Some of the expanded populations in patients were phenotypically characterized and observed to be HLA-DR^<, CD28^<, CD45RA^< and CD45RO⁺, with a greater proportion being CD45RO⁺. Patients had a higher percentage of expression of HLA-DR on both CD4⁺ and CD8⁺ T cells (P< 0.01). The percentages of naive and primed CD4⁺ and CD8⁺ T cells, γδ⁺ T cells and natural killer cells were comparable to those in the control group.     

Vγ9Vδ2 T Cells in Human Legionellosis

In humans, expansion of circulating Vγ9Vδ2 T cells seems to be a pathophysiological denominator shared by protozoan and intracellular bacterial diseases. The assumption was tested here on legionellosis, a condition conforming to the category but not yet described with respect to γδ T cells. Levels of Vγ9Vδ2 T cells in peripheral blood were measured at various intervals in 14 subjects undergoing a Pontiac fever-like disease, shown by serological investigation to be caused by Legionella micdadei. In samples obtained 4 to 6 days after the onset of the disease, the mean percentage (± the standard deviation) of Vγ9Vδ2⁺ T cells among CD3⁺ cells was 1.0% ± 0.5%, compared to 5.0% ± 3.9% in healthy control subjects (P < 0.001). Thereafter, a pronounced increase occurred and at 2 to 7 weeks after onset, mean peak levels were as high as ≈15%. During the next 6 months, values slowly declined, although without reaching the normal range. Percentages of γδ⁺ T cells expressing tumor necrosis factor alpha or gamma interferon in response to phorbol myristate acetate were assayed in vitro. At 14 to 16 days after the onset of disease, the expression of both cytokines was increased (P < 0.01), whereas at 5 to 7 weeks, the expression of tumor necrosis factor alpha was decreased (P < 0.05), possibly reflecting modulation of an inflammatory response. In conclusion, Pontiac fever was found to be associated with a pronounced and long-lasting expansion of Vγ9Vδ2 T cells, implying that the subset may also be pathophysiologically important in a mild and transient form of intracellular bacterial diseases. Surprisingly, the expansion was preceded by a depletion of circulatory Vγ9Vδ2 T cells. Possibly, Vγ9Vδ2 T cells are initially recruited to a site of infection before they expand in response to antigen and occur in high numbers in blood.     

Increased numbers of CD5+ B cells and T cell receptor (TCR) γδ+ T cells are associated with younger age of onset in rheumatoid arthritis (RA)

Patients presenting with RA before the age of 45 years (younger onset) are known to have more aggressive disease compared with patients presenting after the age of 65 years (older onset). Coordinated expansion of circulating CD5⁺ B cell and TCR γδ⁺ T cell levels has been reported in patients with RA. This study assesses the peripheral blood levels of these two cell types in RA patients with younger and older onset of disease. CD5⁺ B cell levels were significantly elevated in the younger onset RA group (26·6 ± 4·5%) compared with the older onset RA group (14·2 ± 1·2%; P <0·01). TCR γδ⁺ T cell levels were also significantly raised in the young patients (4·0 ± 0·9%) compared with elderly patients (1·6 ± 0·2%; P <0·01). T cell levels (CD3⁺) were similar in both groups (young 66·4 ± 3·3%; old 74·3 ± 3·4% (mean ± s.e.m.); NS). Total B cell levels (CD19⁺) were also similar in these groups (7·7 ± 0·7% versus 8·9 ± 1·8%; NS). A significant positive correlation was observed between the CD5⁻ B and TCR γδ⁺ T cell types in the patients (r = 0·72, P <0.05). Compared with age-matched normal controls, the younger onset patients had similar CD5⁺ B cell and TCR γδ⁺ T cell levels to the elderly controls (CD5⁺ B cells 30·2 ± 3·0%; TCR γδ⁺ T cells 3·0 ± 0·8%). Conversely, older onset RA patients had CD5⁺ B cell levels similar to the young controls (12·3 ± 1·9%). Spontaneous in vitro synthesis of immunoglobulins (IgM, IgA and IgG) and rheumatoid factors (IgM and IgA isotypes) were not significantly different in both patient groups. The coordinate expansion of circulating CD5⁺ B cells and γδ⁺ T cells seen in patients with RA presenting before 45 years of age and not after 65 years of age may suggest a potential role for these cells in more aggressive disease states.     

Dietary β-carotene and ultraviolet-induced immunosuppression

Ultraviolet (UV)-induced immunosuppression is a critical step in UV carcinogenesis, permitting tumour outgrowth. We investigated the effect of dietary β-carotene on UV suppression of contact hypersensitivity (CHS) to trinitrochlorobenzene (TNCB) in BALB/c mice. Mice were fed for 10–16 weeks chow alone or supplemented with 1% β-carotene or placebo as beadlets. Serum β-carotene was detectable by high performance liquid chromatography (HPLC) analysis only in β-carotene-fed mice (2.06 ± 0.15 μg/ml). Serum retinol was 0.22–0.27 μg/ml in all three groups. Mice (n = 41/dietary group) were irradiated with 0, 4.5, 9 or 18 kJ/m² of UVB and the CHS response was measured. Decreased CHS responses were observed in all UV-irradiated groups compared with unirradiated controls. UV dose–responses for suppression of CHS derived by first-order regression analyses of plots of percentage suppression of CHS as a function of log₁₀UV dose showed significant slopes (P < 0.02) for all three dietary groups and similar residual variances between groups, P > 0.05. The UV dose for 50% suppression of CHS was 6.3 kJ/m² for control, 6.4 kJ/m² for placebo, and 5.5 kJ/m² for β-carotene-fed mice. No significant differences in slopes or elevations between UV dose–responses were observed, P > 0.05. Skin levels of the initiator of UV-induced immunosuppression, cis urocanic acid, were determined by HPLC in mice given 0 or 9 kJ/m² of UV (n = 28/dietary group). No significant differences were observed between dietary groups (range 35.2–41.1 ng/mg skin, P > 0.15) We conclude feeding β-carotene to BALB/c mice does not alter susceptibility to UV immune suppression, in contrast to human studies.     

Integrins αvβ3 and α5β1 Mediate Attachment of Lyme Disease Spirochetes to Human Cells

Borrelia burgdorferi (sensu lato), the agent of Lyme disease, is able to cause chronic, multisystemic infections in human and animal hosts. Attachment of the spirochete to host cells is likely to be important for the colonization of diverse tissues. The platelet-specific integrin α_IIbβ₃ was previously identified as a receptor for all three species of Lyme disease spirochetes (B. burgdorferi sensu stricto, B. garinii, and B. afzelii). Here we show that B. burgdorferi also recognizes the widely expressed integrins α_vβ₃ and α₅β₁, known as the vitronectin and fibronectin receptors, respectively. Three representatives of each species of Lyme disease spirochete were tested for the ability to bind to purified α_vβ₃ and α₅β₁. All of the strains tested bound to at least one integrin. Binding to one integrin was not always predictive of binding to other integrins, and several different integrin preference profiles were identified. Attachment of the infectious B. burgdorferi strain N40 to purified α_vβ₃ and α₅β₁ was inhibited by RGD peptides and the appropriate receptor-specific antibodies. Binding to α_vβ₃ was also shown by using a transfected cell line that expresses this receptor but not α_IIbβ₃. Attachment of B. burgdorferi N40 to human erythroleukemia cells and to human saphenous vein endothelial cells was mediated by both α₅β₁ and α_vβ₃. Our results show that multiple integrins mediate attachment of Lyme disease spirochetes to host cells.     

Density of γ/δ+ T cells in the jejunal epithelium of patients with coeliac disease and dermatitis herpetiformis is increased with age

Increased density of γ/δ T cell receptor (TCR)⁺ intraepithelial lymphocytes is the only characteristic in the jejunum of patients with coeliac disease and dermatitis herpetiformis which is not normalized on a gluten-free diet. We explored the age-dependent changes in intraepithelial γ/δ and α/β TCR⁺ cells from 137 biopsies from patients with coeliac disease and dermatitis herpetiformis and from controls. Biopsy specimens from 100 patients with coeliac disease and dermatitis herpetiformis and from 37 controls were studied with an immunohistochemical method using MoAbs to T cell receptors and peroxidase staining. An increase in the density of intraepithelial γ/δ T cells above the mean +2 s.d. of the density in controls was present in 97 of 100 specimens from patients with coeliac disease and dermatitis herpetiformis. The density of γ/δ⁺ cells of patients with coeliac disease and dermatitis herpetiformis on a normal gluten-containing diet showed a positive correlation with age (r = 0.45, P< 0.0001). In controls, the density of γ/δ⁺ cells remained low throughout the age-range studies, from age 0.6–57 years. In controls, α/β⁺ cells increased with age (r = 0.57, P< 0.001). The increase in density of intraepithelial lymphocytes with age is in agreement with their thymus-independent character and local proliferation.     

Modulatory Potential of LncRNA Zfas1 for Inflammation and Neuronal Apoptosis in Temporal Lobe Epilepsy

PurposeThis study aimed to elucidate whether lncRNA ZFAS1 is involved in neuronal apoptosis and inflammation in temporal lobe epilepsy (TLE).Materials and MethodsNinety-six TLE patients were recruited, and their peripheral venous blood was gathered to determine Zfas1 expression with polymerase chain reaction. Neurons were separated from hippocampal tissue of newborn SD rats, and si-Zfas1 or pcDNA3.1-Zfas1 was transfected into the neurons. Inflammatory cytokines released by neurons were determined, and neuronal activities were evaluated through MTT assay, colony formation assay, and flow cytometry.ResultsSerum levels of Zfas1 were higher in TLE patients than in healthy controls (p<0.05). Furthermore, Zfas1 expression in neurons was raised by pcDNA3.1-Zfas1 and declined after silencing of Zfas1 (p<0.05). Transfection of pcDNA-Zfas1 weakened the viability and proliferation of neurons and increased neuronal apoptosis (p<0.05). Meanwhile, pcDNA3.1-Zfas1 transfection promoted lipopolysaccharide-induced release of cytokines, including tumor necrosis factor-α, interleukin (IL)-1, IL-6, and intercellular adhesion molecule-1 (p<0.05), and boosted NF-κB activation by elevating the expression of NF-κB p65, pIκBα, and IKKβ in neurons (p<0.05).ConclusionOur results indicated that lncRNA ZFAS1 exacerbates epilepsy development by promoting neuronal apoptosis and inflammation, implying ZFAS1 as a promising treatment target for epilepsy.     

γδ T lymphocyte responses to HIV

Natural immunity may be involved in controlling viral spread in hosts infected with HIV. A panel of γδ T cell receptor-positive lymphocyte clones was isolated from the peripheral blood of healthy HIV⁻ donors and tested for anti-HIV cytotoxic responses. Twelve of 30 (40%) Vγ9⁺Vδ2⁺ T cell clones, but none of seven Vδ1⁺ T cell clones, displayed lytic activity against HIV-infected cells. The Vγ9⁺/Vδ2⁺ clones cytotoxic for HIV-infected cells also lysed Daudi cells. However, not all Vγ9⁺/Vδ2⁺ clones which lysed Daudi targets had the capacity to lyse HIV-infected cells. Some of the γδ T cell clones were also investigated for potential proliferative responses to HIV-infected cells. One Vγ9⁺/Vδ2⁺ T cell clone (ME8-7) and one Vδ1⁺ T cell clone (ME18-2) demonstrated proliferative responses toward HIV-infected cells. Another Vγ9⁺/Vδ2⁺ clone (VM39) proliferated in response to cell-free HIV. Taken together, these results provide direct evidence of anti-HIV γδ T cell responses in healthy, HIV⁻ persons.     

Single-cell analysis reveals the origins and intrahepatic development of liver-resident IFN-γ-producing γδ T cells

γδ T cells are heterogeneous lymphocytes located in various tissues. However, a systematic and comprehensive understanding of the origins of γδ T cell heterogeneity and the extrathymic developmental pathway associated with liver γδ T cells remain largely unsolved. In this study, we performed single-cell RNA sequencing (scRNA-seq) to comprehensively catalog the heterogeneity of γδ T cells derived from murine liver and thymus samples. We revealed the developmental trajectory of γδ T cells and found that the liver contains γδ T cell precursors (pre-γδ T cells). The developmental potential of hepatic γδ T precursor cells was confirmed through in vitro coculture experiments and in vivo adoptive transfer experiments. The adoptive transfer of hematopoietic progenitor Lin⁻Sca-1⁺Mac-1⁺ (LSM) cells from fetal or adult liver samples to sublethally irradiated recipients resulted in the differentiation of liver LSM cells into pre-γδ T cells and interferon-gamma⁺ (IFN-γ⁺) but not interleukin-17a⁺ (IL-17a⁺) γδ T cells in the liver. Importantly, thymectomized mouse models showed that IFN-γ-producing γδ T cells could originate from liver LSM cells in a thymus-independent manner. These results suggested that liver hematopoietic progenitor LSM cells were able to differentiate into pre-γδ T cells and functionally mature γδ T cells, which implied that these cells are involved in a distinct developmental pathway independent of thymus-derived γδ T cells.     

Processing of Mycobacterium tuberculosis Bacilli by Human Monocytes for CD4+ αβ and γδ T Cells: Role of Particulate Antigen

Mycobacterium tuberculosis readily activates both CD4⁺ and Vδ2⁺ γδ T cells. Despite similarity in function, these T-cell subsets differ in the antigens they recognize and the manners in which these antigens are presented by M. tuberculosis-infected monocytes. We investigated mechanisms of antigen processing of M. tuberculosis antigens to human CD4 and γδ T cells by monocytes. Initial uptake of M. tuberculosis bacilli and subsequent processing were required for efficient presentation not only to CD4 T cells but also to Vδ2⁺ γδ T cells. For γδ T cells, recognition of M. tuberculosis-infected monocytes was dependent on Vδ2⁺ T-cell-receptor expression. Recognition of M. tuberculosis antigens by CD4⁺ T cells was restricted by the class II major histocompatibility complex molecule HLA-DR. Processing of M. tuberculosis bacilli for Vδ2⁺ γδ T cells was inhibitable by Brefeldin A, whereas processing of soluble mycobacterial antigens for γδ T cells was not sensitive to Brefeldin A. Processing of M. tuberculosis bacilli for CD4⁺ T cells was unaffected by Brefeldin A. Lysosomotropic agents such as chloroquine and ammonium chloride did not affect the processing of M. tuberculosis bacilli for CD4⁺ and γδ T cells. In contrast, both inhibitors blocked processing of soluble mycobacterial antigens for CD4⁺ T cells. Chloroquine and ammonium chloride insensitivity of processing of M. tuberculosis bacilli was not dependent on the viability of the bacteria, since processing of both formaldehyde-fixed dead bacteria and mycobacterial antigens covalently coupled to latex beads was chloroquine insensitive. Thus, the manner in which mycobacterial antigens were taken up by monocytes (particulate versus soluble) influenced the antigen processing pathway for CD4⁺ and γδ T cells.

Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, is spread readily from person to person by inhalation of aerosolized mycobacteria (8). A hallmark of M. tuberculosis infection is the ability of most healthy individuals to control the infection by mounting an acquired immune response, in which antigen-specific T cells and mononuclear phagocytes arrest the growth of M. tuberculosis bacilli and maintain control over dormant bacilli within granulomas (reviewed in reference 25). This protective cellular immune response results in conversion of the tuberculin skin test from negative to positive and probably in increased resistance to reinfection with tubercle bacilli.CD4⁺ αβ-T-cell-receptor (αβ TCR)-bearing T cells (CD4⁺ T cells) are readily activated by mycobacterial antigens and have a dominant role in the protective immune response to M. tuberculosis in humans (2, 34). These CD4⁺ T cells not only secrete cytokines but also serve directly as cytotoxic effector cells against M. tuberculosis-infected macrophages (6). In addition to CD4⁺ T cells, M. tuberculosis antigens activate other human T-cell subsets such as γδ TCR⁺ T cells (γδ T cells) (15, 16, 18). Vδ2⁺ and Vγ9⁺ γδ T cells are particularly responsive to live M. tuberculosis (15). A role for both γδ and CD4⁺ T cells in protective immunity to acute M. tuberculosis infection has been demonstrated in murine models (20, 21, 26, 27). A recent study of humans suggests that Vγ9⁺ and Vδ2⁺ γδ T-cell numbers and function are reduced in tuberculosis patients (23).Functional comparisons of human CD4⁺ and γδ T-cell responses of healthy tuberculin-positive persons demonstrate that both T-cell subsets have similar cytotoxic effector functions for M. tuberculosis-infected monocytes and produce large amounts of gamma interferon (IFN-γ), with γδ T cells being slightly more efficient producers of IFN-γ than CD4⁺ T cells (37). Despite similarities in function, these two T-cell subsets differ in the mycobacterial antigens recognized by their TCRs and the manners in which antigens are presented to them by M. tuberculosis-infected mononuclear phagocytes. CD4⁺ T cells recognize a wide diversity of mycobacterial peptides in the context of class II major histocompatibility complex (MHC) molecules, which include secreted as well as somatic antigens (6, 13, 33, 37). In contrast, Vγ9⁺ and Vδ2⁺ γδ T cells, the dominant γδ TCR subsets activated by M. tuberculosis, recognize mycobacterial antigens in a non-MHC-restricted manner and the repertoire of antigens includes small phosphate-containing antigens such as TUBag’s (5, 9, 19, 22, 29, 36).Both blood monocytes and alveolar macrophages infected with M. tuberculosis are efficient antigen-presenting cells for mycobacterial antigen-specific CD4⁺ and γδ T cells (1, 5). However, little is known about how M. tuberculosis-infected mononuclear phagocytes process antigens for these two T-cell subsets. M. tuberculosis bacilli are taken up by mononuclear phagocytes through a variety of surface receptors, including complement receptor 4, mannose receptor, and complement receptor 3 (17, 31, 32). Within mononuclear phagocytes, the mycobacteria reside within phagosomes and modulate the phagosome by preventing fusion with acidic lysosomal compartments (7). Although the vacuolar membranes surrounding the phagosome acquire endosomal markers, the vesicular proton ATPase is actively excluded, resulting in an elevated pH of 6.3 to 6.5 compared to the normal lysosomal pH of 4.5 (7, 35). The elevated pH in the phagosome does not appear to inhibit the ability of mycobacterial antigens to be processed and presented to CD4⁺ and Vδ2⁺ γδ T cells. This study was undertaken to gain insight into the mechanisms used by monocytes infected with live M. tuberculosis bacilli to process mycobacterial antigens for presentation to both CD4⁺ and γδ T cells.     

CFTR is a negative regulator of γδ T cell IFN-γ production and antitumor immunity

CFTR, a chloride channel and ion channel regulator studied mostly in epithelial cells, has been reported to participate in immune regulation and likely affect the risk of cancer development. However, little is known about the effects of CFTR on the differentiation and function of γδ T cells. In this study, we observed that CFTR was functionally expressed on the cell surface of γδ T cells. Genetic deletion and pharmacological inhibition of CFTR both increased IFN-γ release by peripheral γδ T cells and potentiated the cytolytic activity of these cells against tumor cells both in vitro and in vivo. Interestingly, the molecular mechanisms underlying the regulation of γδ T cell IFN-γ production by CFTR were either TCR dependent or related to Ca²⁺ influx. CFTR was recruited to TCR immunological synapses and attenuated Lck-P38 MAPK-c-Jun signaling. In addition, CFTR was found to modulate TCR-induced Ca²⁺ influx and membrane potential (V_m)-induced Ca²⁺ influx and subsequently regulate the calcineurin-NFATc1 signaling pathway in γδ T cells. Thus, CFTR serves as a negative regulator of IFN-γ production in γδ T cells and the function of these cells in antitumor immunity. Our investigation suggests that modification of the CFTR activity of γδ T cells may be a potential immunotherapeutic strategy for cancer.     

γδ+ T Cells Preferentially Respond to Live Rather than Killed Malaria Parasites

We have compared the in vitro responses of peripheral blood T cells from malaria-unexposed donors to live Plasmodium falciparum schizonts, freeze-thawed schizont extracts (P. falciparum schizont extracts [PfSE]), and parasite culture supernatants. We show that the cells responding to PfSE and parasite culture supernatants are predominantly CD4⁺ TCRαβ⁺ while in the presence of live schizonts there is an additional activation of TCRγδ⁺ cells. Activation of TCRγδ⁺ cells in response to PfSE was seen only when irradiated autologous feeder cells or recombinant interleukin-2 (IL-2) was added to the cultures. Live schizonts but not PfSE induced significant IL-2 production in vitro in the first 5 days after stimulation, suggesting that induction of early IL-2 by live parasites may contribute to the marked activation of the TCRγδ⁺ population.     

Murine γδ T Lymphocytes Elicited during Plasmodium yoelii Infection Respond to Plasmodium Heat Shock Proteins

γδ T cells accumulate during Plasmodium infections in both murine and human malarias. The biological role of these cells and the antigens that they recognize are not clearly understood, although recent findings indicate that γδ T cells in general influence both innate and antigen-specific adaptive host responses. We examined the accumulation of γδ T cells elicited during infection with virulent and avirulent Plasmodium yoelii parasites in relatively susceptible and resistant strains of mice. Our results indicated that in nonlethal malaria infections, γδ T cells comprise a larger proportion of splenic T cells than in lethal infections and that only a live infection is capable of inducing an increase in the percentage of γδ T cells in vivo. Furthermore, we demonstrate that γδ T cells elicited during a P. yoelii infection respond by proliferation in vitro to P. falciparum heat shock proteins (HSPs) of 60 and 70 kDa, suggesting a possible immunological involvement of parasite HSPs in this arm of the cellular immune response during malarial infection in mice.     

Induction of Thymus-Derived γδ T Cells by Escherichia coli Enterotoxin B Subunit in Peritoneal Cavities of Mice

We examined the activation of intraperitoneal T cells in BALB/c mice by the Escherichia coli enterotoxin B subunit, which induced a specific Th2 type of T-cell response to intraperitoneally coadministered bovine immunoglobulin G. The numbers of both γδ and αβ T cells increased significantly after intraperitoneal administration of the B subunit in a time-dependent manner; these numbers were not affected by the B-subunit G33D mutant, which is defective in GM₁ ganglioside-binding ability. Early after administration a small number of γδ T cells produced either interleukin-4 (IL-4) or gamma interferon, while late after administration primarily IL-10-producing γδ T cells were detected. γδ T cells induced by the B subunit did not express a characteristic V gene over the time course of the study. The induction of γδ T cells did not occur in athymic nu/nu mice but could be induced upon transplantation of fetal AKR thymus-like αβ T cells. γδ T cells in athymic nu/nu mice with a fetal thymic graft predominantly expressed the donor Thy-1.1 antigen but not the host Thy-1.2 antigen. The induction of these T cells, however, could not be restored by coadministration of the B subunit with peritoneal cells from normal mice. These results suggest that the B subunit activates intraperitoneal γδ and αβ T cells in a manner dependent upon its ability to bind to GM₁ ganglioside. γδ T cells induced by the B subunit are Th2-type cells derived from the thymus. These γδ T cells may be functionally involved in specific Th2 responses to the B subunit, which possibly acts as an adjuvant through the influence of αβ T cells.     

Evaluation of Allergenicity on a ω-5 Gliadin-Deficient Cultivar in Wheat-Dependent Exercise-Induced Anaphylaxis

Purposeω-5 gliadin is the major allergen that causes wheat-dependent exercise-induced anaphylaxis (WDEIA). Recently, a missing mutant wheat cultivar at 1B chromosome Glu-B3 and closely linked Gli-B1 loci was bred. This cultivar (ω5D) has a deficiency in ω-5 and γ-gliadins as well as some low-molecular-weight glutenins. We evaluated specific immunoglobulin E (sIgE) reactivity of the ω5D in WDEIA patients compared to wild-type cultivar.MethodsSerum samples from 14 WDEIA and 7 classic wheat allergy patients were used to compare the allergenicity of ω5D and wild-type cultivars using immunoglobulin E immunoblotting, enzyme-linked immunosorbent assay (ELISA), and ImmunoCAP inhibition assays.ResultsImmunoblotting revealed that ω5D extracts had less sIgE binding to gliadins and glutenins in WDEIA sera than wild-type extracts. Immunoblot inhibition assay for gliadin sIgE reactivity also showed that ω5D gliadins had less allergenicity than wild-type gliadins. ELISA inhibition assay showed stronger allergenicity of gliadins than glutenins, although they had cross-reactivity. This assay also showed that the 50% inhibitory concentrations (IC50) of ω5D extracts against gliadin- or glutenin-sIgE reactivity were approximately 4-fold higher in WDEIA patients than those of wild-type extracts. The inhibition capacity of ω5D gliadins against recombinant ω-5 gliadin-sIgE reactivity was also lower in WDEIA patients than that of wild-type.ConclusionsThe allergenicity of the ω5D cultivar is markedly lower for WDEIA patients in the sIgE inhibition tests. These results suggest that the ω5D cultivar may be a safe alternative for WDEIA patients.     

Inverted Vδ1/Vδ2 ratio within the T cell receptor (TCR)-γδ T cell population in peripheral blood of heart transplant recipients

We investigated the levels of TCR-γδ T cells and their subpopulations Vδ1 and Vδ2 in the peripheral blood lymphocytes (PBL) of 28 heart transplant (HTx) patients. Patients (n = 10) receiving cyclosporin A (CsA) for treatment of a nephrotic syndrome (NS) and 10 healthy individuals served as controls. There was no difference in levels of TCR-γδ T cells between the different groups. However, an elevated proportion of Vδ1⁺γδ T cells was found in the PBL of HTx patients, especially when these cells were present in their graft-infiltrating lymphocyte (GIL) cultures. Vδ1⁺γδ T cells of HTx patients showed normal expression of CD45RO and lacked the activation markers CD25 and HLA-DR. After expanding in IL-2-containing medium, PBL cultures of HTx patients more often were dominated by Vδ1 cells than PBL cultures of controls, in which Vδ2 cells were predominantly grown. The aberrant composition of the TCR-γδ population in HTx patients was not a result of immunosuppressive medication, since the proportion Vδ1⁺γδ T cells was normal in the PBL of the NS patients receiving a similar dose of CsA. It is postulated that long-term antigenic stimulation by the graft, at low level, might be responsible for the altered composition of the γδ pool in the HTx patients. Since no donor HLA-specific γδ T cells have been detected, other ligands, such as heat shock proteins, may be involved.     

Role of γδ T lymphocytes in the development of Behçet's disease

Phenotypic and functional properties of γδ T cells, which play an important role in mucocutaneous immunity, were examined to elucidate whether immunological abnormality in Behc¸et's disease may be related to a specific T cell population. We found that CD45RA⁺Vγ9⁺Vδ2⁺γδ T cells, which constitute a minor population of γδ T cells in healthy individuals, were increased in number in Behc¸et's disease irrespective of disease activity. This CD45RA⁺ subset of γδ T cells in the active, but not inactive, phase of this disease expressed IL-2Rβ and HLA-DR, suggesting that they are activated in vivo in active Behc¸et's disease. In addition, the CD45RA⁺γδ T cells produced extreme amounts of tumour necrosis factor and contained perforin granules. These data indicate that a phenotypically distinct subset of γδ T cells, CD45RA⁺CD45RO⁻Vγ9⁺Vδ2⁺, may contribute to immunological abnormalities which may lead to complexity of pathophysiology in Behc¸et's disease.     

γδ T-Cell Function in Pathogenesis of Cerebral Malaria in Mice Infected with Plasmodium berghei ANKA

Mice depleted of γδ T cells by monoclonal antibody treatment and infected with Plasmodium berghei ANKA did not develop cerebral malaria (CM). In striking contrast, δ^0/0 mice infected with P. berghei developed CM despite their γδ T-cell deficiency. γδ T cells appear to be essential for the pathogenesis of CM in mice having experienced normal ontogeny but not in mice genetically deprived of γδ T cells from the beginning of life.