Biomedical subjects

Wolfgang Holtmeier

Publications and source records attributed to Wolfgang Holtmeier.

15 recordsLinked to original sources

PubMed2007

Two groups of porcine TCRgammadelta+ thymocytes behave and diverge differently.

Developmental pathways of gammadelta T cells are still unknown, largely because of the absence of recognized lineage-specific surface markers other than the TCR. We have shown that porcine gammadelta thymocytes can be divided into 12 subsets of the following two major groups: 1) CD4(-) gammadelta thymocytes that can be further subdivided according to their CD2/CD8alphaalpha phenotype, and 2) CD4(+) gammadelta thymocytes that are always CD1(+)CD2(+)CD8alphabeta(+) and have no counterpart in the periphery. In this study, we have analyzed gammadelta thymocyte subsets with respect to behavior during cultivation, cell cycle status, and lymphocyte-specific transcripts. The group of CD4(-) gammadelta thymocytes gives rise to all gammadelta T cells found in the periphery. Proliferating CD2(+)CD8(-)CD1(+)CD45RC(-) gammadelta thymocytes are a common precursor of this group. These precursors differentiate into CD2(+)CD8alphaalpha(+), CD2(+)CD8(-), and CD2(-)CD8(-) gammadelta T cell subsets, which subsequently mature by loss of CD1 and by eventual gain of CD45RC expression. In contrast, the group of CD4(+) gammadelta thymocytes represents transient and independent subsets that are never exported from thymus as TCRgammadelta(+) T cells. In accordance with the following findings, we propose that CD4(+)CD8alphabeta(+) gammadelta thymocytes extinguish their TCRgammadelta expression and differentiate along the alphabeta T cell lineage program: 1) CD4(+) gammadelta thymocytes are actively dividing; 2) CD4(+) gammadelta thymocytes do not die, although their numbers decreased with prolonged cultivation; 3) CD4(+) gammadelta thymocytes express transcripts for RAG-1, TdT, and TCRbeta; and 4) CD4(+) gammadelta thymocytes are able to alter their phenotype to TCRalphabeta(+) thymocytes under appropriate culture conditions.

Animals↗

PubMed2006

Development of the neonatal B and T cell repertoire in swine: implications for comparative and veterinary immunology.

Birth in all higher vertebrates is at the center of the critical window of development in which newborns transition from dependence on innate immunity to dependence on their own adaptive immunity, with passive maternal immunity bridging this transition. Therefore we have studied immunological development through fetal and early neonatal life. In swine, B cells appear earlier in fetal development than T cells. B cell development begins in the yolk sac at the 20th day of gestation (DG20), progresses to fetal liver at DG30 and after DG45 continues in bone marrow. The first wave of developing T cells is gammadelta cells expressing a monomorphic Vdelta rearrangement. Thereafter, alphabeta T cells predominate and at birth, at least 19 TRBV subgroups are expressed, 17 of which appear highly homologous with those in humans. In contrast to the T cell repertoire and unlike humans and mice, the porcine pre-immune VH (IGHV-D-J) repertoire is highly restricted, depending primarily on CDR3 for diversity. The V-KAPPA (IGKV-J) repertoire and apparently also the V-LAMBDA (IGLV-J) repertoire, are also restricted. Diversification of the pre-immune B cell repertoire of swine and the ability to respond to both T-dependent and T-independent antigen depends on colonization of the gut after birth in which colonizing bacteria stimulate with Toll-like receptor ligands, especially bacterial DNA. This may explain the link between repertoire diversification and the anatomical location of primary lymphoid tissue like the ileal Peyers patches. Improper development of adaptive immunity can be caused by infectious agents like the porcine reproductive and respiratory syndrome virus that causes immune dysregulation resulting in immunological injury and autoimmunity.

Allergy and Immunology↗

PubMed2006

Celiac disease.

Celiac disease is a chronic intestinal disease caused by intolerance to gluten. It is characterized by immune-mediated enteropathy, associated with maldigestion and malabsorption of most nutrients and vitamins. In predisposed individuals, the ingestion of gluten-containing food such as wheat and rye induces a flat jejunal mucosa with infiltration of lymphocytes. The main symptoms are: stomach pain, gas, and bloating, diarrhea, weight loss, anemia, edema, bone or joint pain. Prevalence for clinically overt celiac disease varies from 1:270 in Finland to 1:5000 in North America. Since celiac disease can be asymptomatic, most subjects are not diagnosed or they can present with atypical symptoms. Furthermore, severe inflammation of the small bowel can be present without any gastrointestinal symptoms. The diagnosis should be made early since celiac disease causes growth retardation in untreated children and atypical symptoms like infertility or neurological symptoms. Diagnosis requires endoscopy with jejunal biopsy. In addition, tissue-transglutaminase antibodies are important to confirm the diagnosis since there are other diseases which can mimic celiac disease. The exact cause of celiac disease is unknown but is thought to be primarily immune mediated (tissue-transglutaminase autoantigen); often the disease is inherited. Management consists in life long withdrawal of dietary gluten, which leads to significant clinical and histological improvement. However, complete normalization of histology can take years.

Adult↗

PubMed2005

Lymphocyte development in fetal piglets: facts and surprises.

The developing porcine fetus offers an excellent opportunity for the study of lymphocyte development. Studies on B cell, alphabeta T cells and gammadelta T cells in the last decade have expanded our knowledge of lymphocyte development in pigs. These studies have revealed several interesting differences between swine, mice and humans. For example, porcine peripheral lymphocytes include CD4+CD8+ alphabeta T cells and an abundance of gammadelta T cells that may even prevail over the alphabeta population. There are numerous CD2- gammadelta T cells in the blood and a large number of CD8alphaalpha-bearing cells that include NK cells, conventional gammadelta and alphabeta T cells. All porcine B lymphocytes are CD25(lo) and sIgM+ B cells may differ in the expression of CD2 antigen. Unlike mice, porcine B cells appear approximately 2 weeks before T cells and progenitors undergo VDJH rearrangement at 20th day of gestation (DG20) in the yolk sac and DG30 in the fetal liver before consummating high level lymphogenesis in the bone marrow after DG45. Early B cells show an unexpectedly high proportion of in-frame rearrangements, undergo switch recombination in thymus on DG60 and use N-region insertion from the time of the earliest VDJ rearrangement. The genomic repertoire of VH, DH and JH genes is small compared to mice and humans and swine appear to depend on junctional diversity for the majority of their repertoire. The limited VH repertoire of swine contrasts sharply with the porcine TCRbeta repertoire, which is extensive, extraordinarily conserved and nearly identical to that in humans. Therefore, swine present an example of two highly related receptor systems that have diverged in the same species.

Animals↗

PubMed2005

Epithelial defence by gamma delta T cells.

Gamma delta T cells constitute a separate lineage of T lymphocytes which differ from conventional alpha beta T cells with regard to T cell receptor (TCR) repertoire and tissue localization. In murine skin, gamma delta T cells expressing a canonical V gamma5 TCR are abundant and contribute as so-called dendritic epidermal T cells to local immune surveillance. In humans, major subsets of gammadelta T cells are recognized on the basis of their TCR V delta usage. While V delta2 cells dominate in the peripheral blood, V delta1 cells are preferentially localized in mucosal tissue including the intestinal epithelia. In this article we summarize basic features of intraepithelial gamma delta T cells and discuss their possible role in epithelial defence.

Animals↗

PubMed2005

Development of gammadelta thymocyte subsets during prenatal and postnatal ontogeny.

In this report, we describe 12 subpopulations of porcine gammadelta thymocytes based on their expression of CD1, CD2, CD4, CD8- isoforms and CD45RC. Our data suggest that gammadelta thymocytes can be divided into two major families: (a) one large family of CD4-gammadelta thymocytes that could be further subdivided according to the CD2/CD8alphaalpha phenotype and (b) a small family of CD4+ gammadelta thymocytes bearing CD8alphabeta and possessing certain unusual features in comparison with other gammadelta thymocytes. Maturation of gammadelta thymocytes within the CD4- family begins with proliferation of the CD2+ CD8- CD1+ CD45RC- gammadelta common precursor. This developmental stage is followed by diversification into the CD2+ CD8alphaalpha+, CD2+ CD8- and CD2- CD8- subsets. Their further maturation is accompanied by a loss of expression of CD1 and by increased expression of CD45RC. Therefore, individual subsets develop from CD1+ CD45RC- through CD1- CD45RC- into CD1- CD45RC+ cells. On the other hand, gammadelta thymocytes within the CD4+ family bear exclusively CD8alphabeta, always express CD1, but may coexpress CD45RC. These cells have no counterpart in the periphery. Our observations suggest that all peripheral CD8+ gammadelta T cells express CD8alphaalpha and that two subsets of these cells differing in major histocompatibility complex II expression, occur. We propose that one subset acquires CD8alphaalpha in the thymus while the second acquires CD8alphaalpha as a result of stimulation in the periphery.

Animals↗

PubMed2005

gammadelta T cells link innate and adaptive immune responses.

While most T cells use a CD3-associated alpha/beta T cell receptor as antigen recognition structure, a second population of T cells expresses the alternative gamma/delta T cell receptor. gamma/delta T cells are a minor population in the peripheral blood but constitute a major population among intestinal intraepithelial lymphocytes. Most gamma/delta T cells recognize ligands which are fundamentally different from the short peptides that are seen by alpha/beta T cells in the context of MHC class I or class II molecules. Thus, human Vdelta2 T cells recognize small bacterial phosphoantigens, alkylamines and synthetic aminobisphosphonates, whereas Vdelta1 T cells recognize stress-inducible MHC-related molecules MICA/B as well as several other ligands. At the functional level, gamma/delta T cells rapidly produce a variety of cytokines and usually exert potent cytotoxic activity, also towards many tumor cells. In this article, we discuss the role of gamma/delta T cells as a bridge between the innate and the adaptive immune system, based on the interpretation that gamma/delta T cells use their T cell receptor as a pattern recognition receptor. Our increasing understanding of the ligand recognition and activation mechanisms of gamma/delta T cells also opens new perspectives for the development of gamma/delta T cell-based immunotherapies.

Adaptation, Physiological↗

PubMed2004

Prenatal development of the porcine TCR delta repertoire: dominant expression of an invariant T cell receptor Vdelta3-Jdelta3 chain.

The prenatal development of the porcine gamma/delta TCR repertoire was studied by complementarity-determining region 3 (CDR3) spectratyping and sequencing of TRDV1-DV5 transcripts. Specimens from the small and large intestine, spleen, thymus, liver, bone marrow and PBMC from fetal piglets between 38 and 114 days of gestation (DG) were examined. The TCR delta repertoire was highly restricted early in gestation (DG38-DG57) and an invariant TRDV3 transcript, lacking the N/D region, was found in different fetuses throughout gestation and dominated the TRDV3 repertoires of all organs at mid gestation ( approximately DG55). Near the end of gestation, this invariant TRDV3 transcript was absent from the thymus but was still present, in a less dominant manner, in the intestine and spleen. The average CDR3 length of all Vdelta subgroups increased with ontogeny, suggesting an increase in activity of TdT. Thus, the persistence of fetal gamma/delta T cells expressing an invariant TRDV3 chain throughout development is especially surprising since TdT is active early in gestation in swine. We speculate that these gamma/delta T cells might have been selectively expanded by (self)-ligands and may have an important function throughout fetal development.

Amino Acid Sequence↗

PubMed2003

Proliferating intestinal gamma/delta T cells recirculate rapidly and are a major source of the gamma/delta T cell pool in the peripheral blood.

The proliferation, recirculation and repertoire of gut-derived gamma/delta T cells were studied in pigs in vivo. Proliferating gamma/delta T cells (detected by BrdU labeling) are present in all intestinal compartments. In the gut lymph approximately 0.5% of all gamma/delta T cells were proliferating. These gut-derived BrdU(+) gamma/delta T cells re-enter the intestinal tissues, and re-appear in the intestinal lymph far more often than other cells: about 22% of i.v.-injected BrdU(+) gamma/delta T cells were recovered again from the intestinal lymph within 72 h (compare with BrdU(+) B cells 2%, and other BrdU(+) T cells 10%). The contribution of the gut to the migrating gamma/delta T cell pool in the blood became obvious: the proportion of BrdU(+) gamma/delta T cells was three-times larger in control versus cannulated pigs. In 9-month-old pigs, clonally expanded T cells were identified in the intestine by complementarity-determining region 3 spectratyping of TCR-delta transcripts. Such expansions were not visible in the blood or intestinal lymph. The distribution of gamma/delta T cells within the intestinal tract is likely to depend to a large degree on the proliferation and the migratory properties of these cells which are different to those of alpha/beta T cells and B lymphocytes.

Animals↗

PubMed2003

Herpes simplex virus type 2-associated eosinophilic cellulitis (Wells' syndrome).

Eosinophilic cellulitis (Wells' syndrome) is a recurrent inflammatory dermatosis characterized by massive infiltration of eosinophils into the skin. Drugs and pathogens have been recognized causes of eosinophilic cellulitis. We report the repeated association of eosinophilic cellulitis with herpes simplex virus type 2 infections. Antiviral therapy led to a complete remission of eosinophilic cellulitis, indicating that causative treatment of underlying diseases can be effective in controlling eosinophilic cellulitis.

Antiviral Agents↗

PubMed2003

Compartmentalization gamma/delta T cells and their putative role in mucosal immunity.

gamma/delta T cells are an enigmatic group of cells and their functions still remain unknown. The epithelial-associated gamma/delta T cells, which are abundant at mucosal surfaces, are ideally situated to contribute to the initial stages of the immune response. Recent evidence suggests that they recognize stress-induced self-antigens which would enable a homogeneous population of gamma/delta T cells to monitor multiple insults to the epithelium. This could explain the observed oligoclonality and homogeneous distribution of cells carrying identical TCR within mucosal surfaces. However, the analysis of the TCR delta repertoire from different mucosal surfaces indicated that gamma/delta T cells are highly compartmentalized. Thus, gamma/delta T cells are not one homogeneous group of cells which recognize the same (stress-induced) self-antigens, but consist of different subsets that are likely to have distinct functions. It is possible that gamma/delta T cells interact with antigens that are specific for that organ or recognize foreign antigens which are limited to that site. In addition it was shown that gamma/delta T cells can have opposite functions and be proinflammatory or promote epithelial healing. This review focuses on the distribution and repertoire of mucosal gamma/delta T cells and discusses what is currently known about the functions of these cells. Furthermore, their potential role in inflammatory bowel disease is examined.

Animals↗

PubMed2002

Development and compartmentalization of the porcine TCR delta repertoire at mucosal and extraintestinal sites: the pig as a model for analyzing the effects of age and microbial factors.

gammadelta T cells are an important component of the mucosal immune system. Previously, we have shown that the TCR delta repertoire in human intestine is polyclonal at birth and becomes increasingly restricted with age. In this study, we expand those studies to the pig which allows more extensive experiments including several organs. Tissues from different mucosal sites like the stomach, duodenum, ileum, Peyer's patches, jejunum, and colon, and also extraintestinal sites like the lung, spleen, thymus and mesenteric lymph nodes, were obtained from conventionally reared pigs aged 2 wk to 5.5 years. In addition, tissues were also obtained from 10-wk-old specified pathogen- and germ-free pigs. TCRDV1-DV5 transcripts were amplified by RT-PCR after which complementarity-determining region 3 spectratyping was performed. Individual bands were excised from the gels and directly sequenced. The intestinal TCR delta repertoire showed increasing restriction with age and was highly oligoclonal in the adult 2- to 5.5-year-old pigs. In old pigs, we observed a striking compartmentalization. Different TCR delta repertoires were present between the lungs and the intestinal mucosa but also within different parts of the gastrointestinal tract. However, occasionally we observed identical TCR delta transcripts in the intestine and the lungs and shared clones could be detected also along the entire gastrointestinal tract. Thus, subsets of gammadelta T cells are likely to transport immunological information between different compartments of the immune system. Furthermore, these data support the hypothesis that in each mucosal site, different Ags are responsible for selecting and maintaining the gammadelta TCR over time.

Aging↗

PubMed2002

Regional variation of the alphabeta T cell repertoire in the colon of healthy individuals and patients with Crohn's disease.

Clonally expanded T cells might be involved in the pathogenesis of Crohn's disease (CD). To test the impact of CD on the regional distribution of expanded T cells, this study analyzed the T cell receptor beta (TCRB) repertoire within colonic biopsy specimens from 12 CD patients and 6 noninflammatory controls by TCR spectratyping. Migration characteristics of dominant CDR3 bands from different sites of the normal mucosa suggested focal, segmental, or ubiquitous spreading of individual expanded clones. Similar patterns were observed when inflamed and noninflamed areas of the colon of CD patients were compared, suggesting that regional expansion of T cells was more closely related to anatomic proximity than to local inflammatory activity. CDR3-sequence analysis of TCRBV12+ T cells, which were selectively expanded in the inflamed colon of 3 CD patients, failed to reveal a public CDR3 motif. Our data indicate the existence of distinct patterns of regional T cell expansions in the normal gut mucosa, which are not significantly disrupted by chronic intestinal inflammation. This does not exclude a pathogenic role of expanded T cells in CD through more subtle changes, but emphasizes the need to distinguish them from a discontinuous distribution of clonally expanded T cells in normal colon.

Adolescent↗

PubMed2002

Distinct TCR delta repertoires are present in the cutaneous lesions and inflamed duodenum of patients with dermatitis herpetiformis.

Intraepithelial gammadelta T cells are increased in the inflamed small bowel and are also found in increased numbers in cutaneous lesions from patients with dermatitis herpetiformis (DH). Thus, these cells might play an important role in the pathogenesis of the disease. We investigated the T-cell receptor (TCR) delta repertoire in involved and non-involved skin and compared it with the TCR delta repertoire of the inflamed duodenum and peripheral blood of the same patients. An identical TCR delta repertoire in the small bowel and in the cutaneous lesions would suggest a migration of antigen-specific gammadelta T cells from the intestine to the skin which cross-react with cutaneous antigens. T-cell receptor DV1-DV3 transcripts were amplified by reverse transcriptase (RT)-PCR and analyzed by complementarity determining region 3 (CDR3) size spectratyping and nucleotide sequencing. Our results indicate that the cutaneous TCR delta repertoires were oligoclonal and identical dominant gammadelta T-cell clones were present in the involved and non-involved skin. Furthermore, the TCR delta repertoire of the skin was distinct from that in the small bowel. The peripheral blood exhibited a restricted TCR delta repertoire, which differed from that in the intestine and skin. Thus, cutaneous gammadelta T cells are not specifically expanded within the involved skin and are unlikely to be derived from the inflamed duodenum.

Amino Acid Sequence↗

PubMed2002

T cell receptor delta repertoire in inflamed and noninflamed colon of patients with IBD analyzed by CDR3 spectratyping.

Gamma/delta T cells might play an important role in autoimmune conditions like inflammatory bowel disease (IBD). In the present study, we characterized the T cell receptor (TCR)-delta repertoire by complementarity determining region 3 (CDR3) spectratyping in the inflamed and noninflamed mucosa and in the peripheral blood of subjects with Crohn's disease and ulcerative colitis. In contrast to previously published data about alpha/beta T cells, we rarely found oligoclonal expansions of gamma/delta T cells specific only for the inflamed mucosa. The same dominant gamma/delta T cell expansions were also present in the noninflamed colon. Furthermore, the peripheral gamma/delta TCR repertoire was oligoclonal but clearly distinct from that in the inflamed intestine. Thus our results do not support a role for antigen-specific gamma/delta T cells in IBD, and dominant gamma/delta T cells of the peripheral blood are not likely to be derived from the inflamed gut. However, in several patients, the TCR-delta-repertoire was highly diversified, whereas in others we observed a loss of dominant gamma/delta T cell clones when inflamed and noninflamed mucosa were compared. In conclusion, those changes indicate that gamma/delta T cells might play an important role in a subset of patients with IBD.

Amino Acid Sequence↗