Alterations in T-cell receptor Vbeta repertoire of CD4 and CD8 T lymphocytes in human immunodeficiency virus-infected children

Diabetic Wound-Healing Science

Diabetes mellitus is an increasingly prevalent chronic metabolic disease characterized by prolonged hyperglycemia that leads to long-term health consequences. It is estimated that impaired healing of diabetic wounds affects approximately 25% of all patients with diabetes mellitus, often resulting in lower limb amputation, with subsequent high economic and psychosocial costs. The hyperglycemic environment promotes the formation of biofilms and makes diabetic wounds difficult to treat. In this review, we present updates regarding recent advances in our understanding of the pathophysiology of diabetic wounds focusing on impaired angiogenesis, neuropathy, sub-optimal chronic inflammatory response, barrier disruption, and subsequent polymicrobial infection, followed by current and future treatment strategies designed to tackle the various pathologies associated with diabetic wounds. Given the alarming increase in the prevalence of diabetes, and subsequently diabetic wounds, it is imperative that future treatment strategies target multiple causes of impaired healing in diabetic wounds.

Persistent T Cell Repertoire Perturbation and T Cell Activation in HIV After Long Term Treatment

Objective

In people living with HIV (PLHIV), we sought to test the hypothesis that long term anti-retroviral therapy restores the normal T cell repertoire, and investigate the functional relationship of residual repertoire abnormalities to persistent immune system dysregulation.

Methods

We conducted a case-control study in PLHIV and HIV-negative volunteers, of circulating T cell receptor repertoires and whole blood transcriptomes by RNA sequencing, complemented by metadata from routinely collected health care records.

Results

T cell receptor sequencing revealed persistent abnormalities in the clonal T cell repertoire of PLHIV, characterized by reduced repertoire diversity and oligoclonal T cell expansion correlated with elevated CD8 T cell counts. We found no evidence that these expansions were driven by cytomegalovirus or another common antigen. Increased frequency of long CDR3 sequences and reduced frequency of public sequences among the expanded clones implicated abnormal thymic selection as a contributing factor. These abnormalities in the repertoire correlated with systems level evidence of persistent T cell activation in genome-wide blood transcriptomes.

Conclusions

The diversity of T cell receptor repertoires in PLHIV on long term anti-retroviral therapy remains significantly depleted, and skewed by idiosyncratic clones, partly attributable to altered thymic output and associated with T cell mediated chronic immune activation. Further investigation of thymic function and the antigenic drivers of T cell clonal selection in PLHIV are critical to efforts to fully re-establish normal immune function.

Biological Aging and Immune Senescence in Children with Perinatally Acquired HIV

Chronic HIV-infected children suffer from premature aging and aging-related diseases. Viral replication induces an ongoing inflammation process, with the release of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), the activation of the immune system, and the production of proinflammatory cytokines. Although combined highly active antiretroviral therapy (ART) has significantly modified the natural course of HIV infection, normalization of T and B cell phenotype is not completely achievable; thus, many HIV-infected children display several phenotypical alterations, including higher percentages of activated cells, that favor an accelerated telomere attrition, and higher percentages of exhausted and senescent cells. All these features ultimately lead to the clinical manifestations related to premature aging and comorbidities typically observed in older general population, including non-AIDS-related malignancies. Therefore, even under effective treatment, the premature aging process of HIV-infected children negatively impacts their quality and length of life. This review examines the available data on the impact of HIV and ART on immune and biological senescence of HIV-infected children.

Lymphocyte homeostasis is maintained in perinatally HIV-infected patients after three decades of life

Background

While immunosenescence, defined as reduced production of new lymphocytes, restriction of T-cell receptor repertoire and telomeres shortening, has been extensively evaluated in HIV-infected children and adults, no data about these parameters are available in perinatally-infected patients with very long-lasting HIV infection.

Methods

We compared thymic and bone marrow output, telomere length (measured by Real-Time PCR) and T-cell receptor repertoire (determined by spectratyping) of 21 perinatally HIV-infected subjects (with a median of 27 years of infection) with those of 19 age-matched non-perinatally HIV-infected patients and 40 healthy controls. All patients received a combined antiretroviral therapy.

Results

While thymic and bone marrow output were not different among the analyzed groups, telomere length in peripheral blood cells and T-cell receptor diversity were significantly lower in HIV-perinatally and non-perinatally infected individuals compared to healthy controls.

Conclusions

In HIV-infected subjects, a normal thymic output together with a reduced telomere length and a restricted T-cell receptor repertoire could be explained by the shift of newly produced cells into memory subsets. This phenomenon may allow to control viral infection and maintain peripheral homeostasis.

Shorter TCR β-Chains Are Highly Enriched During Thymic Selection and Antigen-Driven Selection

The adaptive immune system uses several strategies to generate a repertoire of T cell receptors (TCR) with sufficient diversity to recognize the universe of potential pathogens. However, it remains unclear how differences in the T cell receptor (TCR) contribute to heterogeneity in T cell state. In this study, we used polychromatic flow cytometry to isolate highly pure CD4+/CD8+ naive and memory T cells, and applied deep sequencing to characterize corresponding TCR β-chain (TCRβ) complementary-determining region 3 (CDR3) repertoires. We find that shorter TCRβ CDR3s with fewer insertions were highly enriched during thymic selection. Antigen-experienced T cells (memory T cells) harbor shorter CDR3s vs. naive T cells. Moreover, the public TCRβ CDR3 clonotypes within cell subsets or interindividual tend to have shorter CDR3 length and a significantly larger size compared with "private" clonotypes. Taken together, shorter CDR3s highly enriched during thymic selection and antigen-driven selection, and further enriched in public T-cell responses. These results indicated that it may be evolutionary pressures drive short CDR3s to recognize most of antigen in nature.

Study of the T-cell receptor repertoire by CDR3 spectratyping

The T-cell receptor (TCR) is the key player within the so called immunological synapse and the analysis of its repertoire offers a picture of both versatility and wideness of the whole immune T-cell compartment. Among the different approaches applied to its study the so-called spectratyping identifies the pattern of the third complementarity determining region (CDR3) length distribution in each one of the beta variable (TRBV) subfamilies encoded by the corresponding genes. This technique consists in a CDR3 fragment analysis through capillary electrophoresis, performed after cell separation, RNA extraction and reverse transcriptase PCR. This review will run through the most relevant studies which have tried to dissect the TCR repertoire usage in patients with different immune-mediated and infective diseases as well as solid or haematologic malignancies.

Impaired T-cell differentiation in diabetic foot ulceration

Foot ulceration is one of the most debilitating complications associated with diabetes, but its cause remains poorly understood. Several studies have been undertaken to understand healing kinetics or find possible therapies to enhance healing. However, few studies have been directed at understanding the immunological alterations that could influence wound healing in diabetes. In this study, we analysed the T-cell receptor (TCR) repertoire diversity in TCR-αβ⁺ T cells. We also analysed the distribution and phenotype of T cells obtained from the peripheral blood of healthy controls and diabetic individuals with or without foot ulcers. Our results showed that diabetic individuals, especially those with foot ulcers, have a significantly lower naive T-cell number and a poorer TCR-Vβ repertoire diversity. We also showed that the reduced TCR-Vβ repertoire diversity in diabetic individuals was mainly owing to the accumulation of effector T cells, the major source of tumour necrosis factor-α production, which was even more pronounced in patients with acute foot ulceration. Moreover, the expression of several inflammatory chemokine receptors was significantly reduced in diabetic patients. In conclusion, effector T-cell accumulation and TCR repertoire diversity reduction appear to precede the development of foot ulcers. This finding may open new immunological therapeutic possibilities and provide a new prognostic tool in diabetic wound care.

T-cell receptor phenotype pattern in atopic children using commercial fluorescently labeled antibodies against 21 human class-specific v segments for the tcrβ chain (vβ) of peripheral blood: a cross sectional study

BACKGROUND

T-cell receptor (TCR) repertoire development is an integral part of the adaptive immune response. T-cell activation requires recognition of appropriately processed antigens by the TCR. Development of a diverse repertoire of TCRs is therefore essential to ensure adequate protection from potential threats. The majority of T-cells in peripheral blood have TCRs composed of an alpha and a beta chain. At the DNA level, the TCR genes are formed through directed recombination from germline sequences-the so-called VDJ recombination [variable (V) joining (J) diversity (D) gene segments] which results in variations in the repertoire. The most variable part of TCRs is the Vβ region (VβTCR), which has multiple V segment families that can be quantitatively measured. However, only sparse data exists on the normal levels of the VβTCR repertoire in healthy children. We aimed to establish normal values for the VβTCR repertoire in atopic children without immunodeficiency.

METHODS

Fifty-three children were recruited from food allergy, drug allergy, chronic urticaria and anaphylaxis registries and were divided into groups based on age: >0-2 years, 3-6 years, and 6-18 years. We used commercially available and fluorescently labeled antibodies against 21 human class-specific V segments of the TCRβ chain (Vβ) to study in peripheral blood the quantitative pattern of Vβ variation by flow cytometry.

RESULTS

Children of all ages exhibited a similar pattern of TCR Vβ expression. Vβ 2 was the most commonly expressed family in all three age groups [9.5 % (95 % CI, 8.9, 10 %), 8.8 % (95 % CI, 7.4, 10.2 %) and 7.6 % (7.0, 8.3 %) respectively]. However, the percentage of Vβ 2 decreased in older children and the percentage of Vβ 1 was higher in males. TCR Vβ expression in our sample of atopic children did not differ substantially from previously published levels in non-atopic cohorts.

CONCLUSION

TCR Vβ diversity follows a predictable and comparable pattern in atopic and healthy non-atopic children. Establishing normal levels for healthy children with and without atopy will contribute to a better definition of Vβ receptor deviation in children with primary immunodeficiency and/or immunodysregulation conditions.

Dynamic Perturbations of the T-Cell Receptor Repertoire in Chronic HIV Infection and following Antiretroviral Therapy

HIV infection profoundly affects many parameters of the immune system and ultimately leads to AIDS, yet which factors are most important for determining resistance, pathology, and response to antiretroviral treatment – and how best to monitor them – remain unclear. We develop a quantitative high-throughput sequencing pipeline to characterize the TCR repertoires of HIV-infected individuals before and after antiretroviral therapy, working from small, unfractionated samples of peripheral blood. This reveals the TCR repertoires of HIV⁺ individuals to be highly perturbed, with considerably reduced diversity as a small proportion of sequences are highly overrepresented. HIV also causes specific qualitative changes to the repertoire including an altered distribution of V gene usage, depletion of public TCR sequences, and disruption of TCR networks. Short-term antiretroviral therapy has little impact on most of the global damage to repertoire structure, but is accompanied by rapid changes in the abundance of many individual TCR sequences, decreases in abundance of the most common sequences, and decreases in the majority of HIV-associated CDR3 sequences. Thus, high-throughput repertoire sequencing of small blood samples that are easy to take, store, and process can shed light on various aspects of the T-cell immune compartment and stands to offer insights into patient stratification and immune reconstitution.

Role of TLR4 and TCR or BCR against baicalin-induced responses in T and B cells

Baicalin (BA), a flavonoid compound isolated from Scutellaria baicalensis, has been shown to possess a number of pharmacological effects including antiviral, anti-inflammatory, antioxidant and immune regulation. Here, we examined its effects on human T and B cells proliferation by MTT assay and found that BA stimulated T and B cells proliferation, independently and cooperatively with Con-A (T cells) or LPS (B cells). Then, we analyzed the effects of BA treatment on the mRNA expression of Toll-like receptors (TLRs), IL-2, IFN-γ and IL-12 in T and B cells by real-time RT-PCR and attempted to observe whether blocking TLR4 had influence on mRNA expression. We found that BA treatment significantly up-regulated TLR3, 7, 8 and 9 mRNA expressions in T and B cells, IL-2 and IFN-γ in T cells and IL-12 in B cells. The increased mRNA expressions were suppressed after blocking TLR4. We further analyzed the effects of BA treatment on TCR vβ and CD79 mRNA expression levels in T and B cells and explored whether blocking TCR (αβ) or BCR mIgM F(ab')(2) had an influence on mRNA expression. We found that BA treatment significantly improved TCR vβ and CD79 mRNA expression in T and B cells, respectively, and the improvements were all inhibited after blocking TCR (αβ) or BCR mIgM F(ab')(2). Our results suggested that BA participates in innate and adaptive immune regulation by up-regulating the mRNA expression of TLRs (3, 7, 8 and 9), IL-2, IFN-γ and IL-12 in T and B cells, which is mediated by TLR4, and by improving the mRNA expression of TCR vβ and CD79, which is mediated by TCR (αβ) and BCR mIgM, respectively. Therefore, TLR4, TCR (αβ) and BCR mIgM are all the immune receptors for BA on T and B cells.

Role of the Fas/FasL pathway in HIV or SIV disease

Human immunodeficiency virus disease involves progressive destruction of host immunity leading to opportunistic infections and increased rates for malignancies. Both depletion in immune cell numbers as well as defects in their effector functions are responsible for this immunodeficiency The broad impact of HIV reflects a similarly broad pattern of cell depletion including subsets that do not express viral receptors or support viral replication. Indirect cell killing, the destruction of uninfected cells, is due partly to activation of the Fas/FasL system for cell death. This death-signaling pathway is induced during HIV disease and contributes significantly to viral pathogenesis and disease.

Significantly skewed memory CD8+ T cell subsets in HIV-1 infected infants during the first year of life

HIV-1 infection causes a severe T cell compromise; however, little is known about changes in naive, memory, effector and senescent T cell subsets during the first year of life. T cell subsets were studied over the first year of life in blood from 3 infant cohorts: untreated HIV-infected, HIV-exposed but uninfected, and HIV-unexposed. In HIV-infected infants, the frequency of CCR7(+)CD45RA(+) naive CD8(+) T cells was significantly decreased, while the frequency of CCR7(-)CD45RA(-) effector memory CD8(+) T cells was increased, compared with the control cohorts. A larger population of CD8(+) T cells in HIV-infected infants displayed a phenotype consistent with senescence. Differences in CD4(+) T cell subset frequencies were less pronounced, and no significant differences were observed between exposed and unexposed HIV-uninfected infants. We concluded that the proportion of naive, memory, effector and senescent CD8(+) T cells during the first year of life is significantly altered by HIV-1 infection.

An improved design of PCR primers for detection of human T cell receptor beta chain repertoire

Analysis of T cell receptor beta variable region (TCRBV) gene rearrangement is useful for clonal assessment of abnormal T cell proliferations in various diseases. However, most primer panels previously used can only amplify the third complementarity-determining region. Following IMGT database we established a panel of primers, which can amplify entire sequences of all functional TCRBV families. To confirm the usefulness of this panel of primers, we detected different TCRBV repertoires. In 15 healthy donors, most of the BV families were expressed and appeared as a Gaussian distribution. 13 acute myeloid leukemia patients showed monoclonal or oligoclonal changes of BV15 family, and some of them also had monoclonal or oligoclonal expansion of BV2, BV4, BV6 or BV13 families. In one patient after allo-hematopoietic stem cell transplantation, monoclonal proliferation of BV10 family occurred during graft-versus-host disease. In conclusion, this panel of primers improves our abilities to analyze TCRBV repertoire changes in related diseases.

Mycosis fungoides and Sézary syndrome

Mycosis fungoides and Sézary syndrome are the most common of the cutaneous T-cell lymphomas, which are a heterogeneous group of neoplasms that affect the skin as a primary site. Although the aetiologies of mycosis fungoides and Sézary syndrome are unknown, important insights have been gained in the immunological and genetic perturbations that are associated with these diseases. Unlike some B-cell lymphomas, cutaneous T-cell lymphomas as a group are rarely if ever curable and hence need chronic-disease management. New approaches to treatments are being investigated and include biological and cytotoxic drugs, phototherapy, and monoclonal antibodies that are directed towards novel molecular targets. New molecular technologies such as complementary-DNA microarray have the potential to increase the accuracy of diagnosis and provide important prognostic information. Treatments can be combined to greatly improve clinical outcome without substantially increasing toxic effects in advanced disease that is otherwise difficult to treat. Although present treatment strategies are generally not curative, there is hope that experimental treatments, particularly immunotherapy, might eventually reverse or suppress the abnormalities of mycosis fungoides and Sézary syndrome to the point at which they become non-life-threatening, chronic diseases.

T cell receptor Vbeta repertoire of T lymphocytes and T regulatory cells by flow cytometric analysis in healthy children

Evaluation of the T cell receptor (TCR) Vbeta repertoire by flow cytometric analysis has been used for studying the T cell compartments for diseases in which T cells are implicated in the pathogenesis. For the interpretation of these studies information is needed about Vbeta usage in healthy individuals and there are few data for normal usage in paediatric populations. We examined the T lymphocyte (sub)populations in 47 healthy controls (age range: 3 months-16 years). We found non-random Vbeta usage with skewed reactivity of some families towards CD4+ or CD4- T cells. Importantly, there appeared to be no significant change in Vbeta usage according to age group. Some controls showed expansions in some Vbeta families, although incidence of such expansions was low. We went on to examine the repertoire of CD4+CD25(Bright) T regulatory cells in 25 healthy controls. We found overlapping quantitative usage for each of the Vbeta families between CD4+CD25- and CD4+CD25(Bright) T cells. However, there was a significant preferential usage for five Vbeta families and decreased usage of two Vbeta families in the CD4+CD25(Bright) T cells, suggesting that although they overlap there may be subtle but important differences in the TCR repertoire of T regulatory cells.

Distribution and evolution of T-cell receptor Vbeta repertoire on peripheral blood lymphocytes of newborn infants of human immunodeficiency virus (HIV)-infected mothers: differential display on CD4 and CD8 T cells and effect of HIV infection

Neonatal human peripheral blood mononuclear cells from 12 human immunodeficiency virus (HIV)-infected and 84 uninfected children were assessed for their distribution of T-cell receptors (TCRs) by flow cytometry employing monoclonal antibodies to 14 Vbeta types. Vbeta 2, 5c, and 13 were the most commonly found on CD4 cells (in that order). There was a bimodal distribution of Vbeta 2, being most common in 48% of individuals but in limiting frequency (<2% of CD4) in 21%. Vbeta 2, 3, 8b, and 13 were most commonly expressed on CD8 cells at similar frequencies. There was little difference in the pattern displayed among the infected compared to that of the uninfected. The variation of the distribution over time was studied in 12 infants (7 infected). Only a single HIV-infected child had a significant difference in the interquartile range; none of the HIV-negative patients showed a significant difference. In conclusion, newborns demonstrate different distributions of TCR Vbeta types on CD4 and CD8 cells. HIV infection produces no change in neonatal TCR and little change over the course of 2 years compared to that seen in the uninfected.

Characterization of the T-cell receptor Vbeta repertoire in the human immune response against Leishmania parasites

In order to explore a possible presence of hyperreactive T-cell clones in human cutaneous leishmaniasis (CL), we have investigated, by flow cytometry, the expression of Vbeta chains of T-cell receptors (TCRs) in the following types of cells: (i) peripheral blood mononuclear cells (PBMCs) from CL patients, which were then compared to those from normal volunteers; (ii) unstimulated and soluble Leishmania antigen-stimulated draining lymph node cells from CL patients; (iii) PBMCs from volunteers before versus after Leishmania immunization; and (iv) PBMCs from healthy volunteers that were primed in vitro with live Leishmania parasites. Our results show a modulation in the TCR Vbeta repertoire during CL and after antigen stimulation of patients' cells. Vaccination, however, leads to a broad expansion of different Vbeta TCRs. We also observed an association between TCR Vbeta12 expression, T-cell activation, and gamma interferon production upon in vitro priming with Leishmania. Collectively, these results both indicate that infection with live parasites or exposure to parasite antigen can modulate the TCR Vbeta repertoire and suggest that TCR Vbeta12 may be implicated in the response to Leishmania.

Simplified fluorescent multiplex PCR method for evaluation of the T-cell receptor V beta-chain repertoire

RATIONALE

Evaluation of the T-cell receptor (TCR) V beta-chain repertoire by PCR-based CDR3 length analysis allows fine resolution of the usage of the TCR V beta repertoire and is a sensitive tool to monitor changes in the T-cell compartment. A multiplex PCR method employing 24 labeled upstream V beta primers instead of the conventionally labeled downstream C beta primer is described.

METHOD

RNA was isolated from purified CD4 and CD8 T-cell subsets from umbilical cord blood and clinical samples using TRI reagent followed by reverse transcription using a C beta primer and an Omniscript RT kit. The 24 V beta primers were multiplexed based on compatibility and product sizes into seven reactions. cDNA was amplified using 24 V beta primers (labeled with tetrachloro-6-cardoxyfluorescein, 6-carboxyfluorescein, and hexachloro-6-carboxyfluorescein), an unlabeled C beta primer, and Taqgold polymerase. The fluorescent PCR products were resolved on an automated DNA sequencer and analyzed using the Genotyper 2.1 software.

RESULTS

V beta spectratypes of excellent resolution were obtained with RNA amounts of 250 ng using the labeled V beta primers. The resolution was superior to that obtained with the labeled C beta primer assay. Also the numbers of PCRs were reduced to 7 from the 12 required in the C beta labeling method, and the sample processing time was reduced by half.

CONCLUSION

The method described for T-cell receptor V beta-chain repertoire analysis eliminates tedious dilutions and results in superior resolution with small amounts of RNA. The fast throughput makes this method suitable for automation and offers the feasibility to perform TCR V beta repertoire analyses in clinical trials.