Human CD1a Research Articles

Depletion of Langerhans cells in the tongue from patients with advanced‐stage acquired immune deficiency syndrome: relation to opportunistic infections

To quantify and compare the expression of Langerhans cells (LCs) in the tongue mucosa of AIDS patients with different opportunistic infections, and from acquired immune deficiency syndrome (AIDS) and non-AIDS patients with normal tongues, using autopsy material. Human leucocyte antigen D-related (HLA-DR), CD1a and CD83 antibodies were used to identify and quantify LCs by immunohistochemistry in tongue tissue of 40 AIDS patients (10 with lingual candidiasis, 10 with lingual herpes, 10 with oral hairy leukoplakia and 10 with no lesions) and 23 tongues from human immunodeficiency virus (HIV)-negative control patients. Quantification was performed by means of conventional morphometry in four different regions (anterior, middle, posterior and lateral) of the tongue. The results were expressed as positive cells per area of epithelium. The AIDS patients presented a lower density of CD1a(+) cells (P < 0.001), HLA-DR (P < 0.003) and CD83 (P < 0.001) in all regions of the tongue compared to the non-AIDS control group. However, no differences in any of the markers were found when AIDS patients with different opportunistic infections were compared with AIDS patients without tongue infection. Advanced stage AIDS patients showed a depletion of LCs in the tongue mucosa. HIV infection induces cytopathic changes in LCs, contributing to their depletion regardless of the presence of oral infections.

Polymorphism of human CD1a, CD1d, and CD1e in exon 2 in Chinese Han and She ethnic populations

CD1 molecules are the major histocompatibility complex (MHC)-like glycoproteins specialized in capturing and presenting a variety of glycolipid to antigen-specific T-cells. There are five closely linked CD1 genes termed as CD1a, CD1b, CD1c, CD1d, and CD1e. CD1 gene features limited the polymorphism in exon 2 which encodes for the alpha1 domain. Few investigations on the allele frequencies of the CD1 genes have been reported to date; however, variation of CD1 allele frequency in different ethnics has been observed. In the current study, the CD1a, CD1d, and CD1e gene polymorphisms in exon 2 (alleles 01 and 02) in a group of normal Chinese Han and She individuals were analyzed. Similar allele prevalence was observed between the two populations. The CD1e allele frequency was 37.1% (allele 01); 62.9% (allele 02) and 39.3% (allele 01); 60.7% (allele 02) for Han and She populations, respectively. CD1e was the only polymorphic gene with a genotype frequency for Chinese Han (01/01, 11.0%; 01/02, 52.2%; 02/02, 36.8%) and She (01/01, 13.2%; 01/02, 52.1%; 02/02, 34.7%) individuals, respectively. No CD1a allele 01 and CD1d allele 02 were observed in either population. Our findings indicate that the polymorphism of CD1a, CD1d, and CD1e genes in exon 2 is very limited in the Chinese Han and She ethnics.

Chemokine Receptor CCR5 Mediates AlloImmune Responses in Graft-versus-Host Disease

Allogeneic bone marrow transplantation (BMT) is an effective therapy for hematologic malignancies. However graft-versus-host disease (GVHD) is a major limiting factor for a successful patient outcome. GVHD is a result of alloimmune responses of donor T lymphocytes attacking the recipient's cells and tissues. Chemokine receptor CCR5 plays a role in solid organ allograft rejection and mediates murine GVHD pathogenesis. Herein, we report that infiltrating lymphocytes in the skin of human acute GVHD (aGVHD) samples are predominantly CCR5(+) T cells. In addition, we characterized the features of the CCR5 expression on alloreactive T lymphocytes. We found that the CCR5(+) population exhibits the characteristics of the activated effector T cell phenotype. CCR5 expression is upregulated upon allogenic stimulation, and CCR5(+) cells are proliferating with coexpression of T cell activation markers. Furthermore, the activated T cells producing inflammatory cytokine tumor necrosis factor (TNF)alpha, interleukin (IL)-2, or interferon (IFN)-gamma, are positive for CCR5. Thus, CCR5 is a marker for GVHD effector cells and CCR5(+) T cells are active participants in the pathogenesis of human aGVHD.

Selective Transduction of Mature DC in Human Skin and Lymph Nodes by CD80/CD86-targeted Fiber-modified Adenovirus-5/3

In vivo targeting of dendritic cells (DC) represents an attractive alternative to currently apply ex vivo DC-based genetic tumor vaccination protocols. Finding the optimal vector for in vivo targeting of DC is important for such strategies. We, therefore, tested a panel of subgroup C/B chimeric and fiber-modified adenoviruses (Ads) for their relative capacity to transduce human DC. We made use of in vitro generated Langerhans cells, and of ex vivo human skin and melanoma-draining lymph node derived DC. Of the tested viruses the C/B-chimeric adenovirus serotype 5 (Ad5)/3 virus most efficiently transduced in vitro generated Langerhans cells. In addition, Ad5/3 preferentially targeted mature myeloid DC from human skin and draining lymph node and transduced them at significantly higher frequencies than Ad5. In addition, Ad5/3 was more specific for mature human skin-derived CD1a+ CD83+ DC than the previously reported DC-transducing C/B-chimeric vector Ad5/35, infecting less bystander cells. It was previously reported that Ad5/3 transduced human monocyte-derived DC by binding to the B7 molecules CD80 and CD86. High-efficiency transduction of mature skin-derived DC was similarly shown to be mediated through binding to CD80/CD86 and not to interfere with subsequent T-cell priming. We conclude that Ad5/3, in combination with DC-activating adjuvants, represents a promising therapeutic tool for the in vivo transduction of mature DC, and may be less likely to induce unwanted side effects such as immune tolerance through the infection of nonprofessional antigen-presenting cells.

Synthesis of Dideoxymycobactin Antigens Presented by CD1a Reveals T Cell Fine Specificity for Natural Lipopeptide Structures

Mycobacterium tuberculosis survival in cells requires mycobactin siderophores. Recently, the search for lipid antigens presented by the CD1a antigen-presenting protein led to the discovery of a mycobactin-like compound, dideoxymycobactin (DDM). Here we synthesize DDMs using solution phase and solid phase peptide synthesis chemistry. Comparison of synthetic standards to natural mycobacterial mycobactins by nuclear magnetic resonance and mass spectrometry allowed identification of an unexpected alpha-methyl serine unit in natural DDM. This finding further distinguishes these pre-siderophores as foreign compounds distinct from conventional peptides, and we provide evidence that this chemical variation influences the T cell response. One synthetic DDM recapitulated natural structures and potently stimulated T cells, making it suitable for patient studies of CD1a in infectious disease. DDM analogs differing in the stereochemistry of their butyrate or oxazoline moieties were not recognized by human T cells. Therefore, we conclude that T cells show precise specificity for both arms of the peptide, which are predicted to lie at the CD1a-T cell receptor interface.

An in vivo model of the human CD1 antigen presenting system (42.24)

Abstract CD1 molecules are a family of antigen presenting molecules that present lipids and glycolipids for recognition by specialized T cells. The CD1 system has been implicated in microbial infections, autoimmune and allergic disorders, and immunological control of tumors. However, our understanding of its role in human disease remains limited because animal models that resemble the human CD1 system are lacking. Here we report that a severely immune deficient mouse engrafted with human fetal tissues and hematopoietic stem cells develops an intact human CD1 antigen presenting system. Human CD1a, b, c, and d isoforms are highly expressed in the thymic organoid that develops in the engrafted mice, and histological analysis indicates the presence of CD1a+ APCs. Moreover, CD1+ APCs are expressed in peripheral tissues including the spleen and liver, and are capable of presenting bacterial glycolipids to human T cells specific for CD1a, b, or c. Staining with CD1d tetramers detected comparable percentages of human CD1d-restricted T cells in engrafted mice and human blood, and CD1d-restricted T cells isolated from the mice expressed a characteristic Vα24+/Vβ11+ TCR and recognized the glycolipid antigen α-GalCer. These results demonstrate the functional reconstitution of the human CD1 system in a mouse model.

Expression of blood dendritic cell antigens (BDCAs) by CD1a + human pulmonary cells

Myeloid and plasmacytoid dendritic cell (DC) subsets have been recently identified in the human lung based on their differential expression of Blood DC Antigens 1-3 (BDCAs). We investigated the expression of these antigens by isolated human pulmonary CD1a(+) DCs, namely Langerhan's cells. Using an in vitro cell culture system we successfully isolated a population of relatively pure (>70%) CD1a(+) cells from human lung tissue (n=5 subject samples) and stained these with antibodies against the myeloid DC markers BDCA1 (CD1c) and BDCA3 (CD303), the plasmacytoid DC marker BDCA2 (CD141), the Langerhan's cell marker Langerin and the maturation marker CD83. Among different subject samples, the isolated CD1a(+) cells showed variable expression of Langerin, BDCAs and CD83. Interestingly, in two subject samples, which contained >70% CD83(+) mature CD1a(+) cells, >50% of the cells were positive for all of the BDCAs. We conclude that isolated pulmonary CD1a(+) DCs in vitro have the capacity to express both myeloid and plasmacytoid BDCA markers and that rather than subset restriction in pulmonary DCs, a significant degree of flexibility/plasticity can be induced, albeit experimentally.

Dendritic cell populations in the eutopic and ectopic endometrium of women with endometriosis

Immune alterations may be involved in the pathogenesis and progression of endometriosis. Dendritic cells (DCs) are potent antigen presenting cells that are highly involved in the initiation of the immune response. The aim of this study was to investigate DC populations in the eutopic and ectopic endometrium of women with endometriosis compared with controls. Hysterectomy samples were obtained from premenopausal women with (n = 33) and without (n = 28) endometriosis. In addition, paired peritoneal endometriotic lesions and uterine curettings were collected from 32 women with endometriosis. Specimen sections were stained immunohistochemically using antibodies for monoclonal mouse antibodies directed against human CD1a and CD83, which are specific for immature and mature DCs, respectively. The mean density of endometrial CD1a+ DCs in the basal layer was significantly increased in women with endometriosis compared with controls during the proliferative phase only (P = 0.001). There was a highly significant decrease in the density of endometrial CD83+ DCs in women with endometriosis compared with controls in both layers of the endometrium across all phases of the menstrual cycle (P = 0.001). The density of CD1a+ DCs was significantly increased in peritoneal endometriotic lesions (P = 0.003) and in the surrounding peritoneum (P = 0.001) compared with paired uterine curettings and peritoneum distant from the lesion. Both CD1a+ and CD83+ DC populations were altered in the eutopic and ectopic endometrium of women with endometriosis compared with controls. Alterations in these cells, which play a crucial role in the coordination of the immune response, may be involved in pain generation and the pathogenesis of endometriosis.

EFALIZUMAB-INDUCED ISOLATED CEREBRAL LUPUS-LIKE SYNDROME

Drug-induced lupus erythematosus has been recognized as a side effect of more than 80 drugs since its first description in association with sulfadiazine in 1945.1 Novel bioengineered agents for treatment of autoimmune disorders can also induce lupus-like syndromes. This is especially described for tumor necrosis factor alpha (TNFα) antagonists.2,3 Efalizumab is an immunosuppressive recombinant humanized IgG1 kappa isotype monoclonal antibody that binds to human CD11a. It is indicated for the treatment of adult patients with chronic moderate to severe plaque type psoriasis.4 Although efalizumab was been used for treatment of refractory subacute cutaneous lupus erythematosus,5 this drug can also induce the cutaneous form of this disease.6 However, a cerebral lupus-like syndrome has not been reported in association with efalizumab. We report a 56-year-old man who was admitted to the hospital because of psychosyndrome and movement disorder. His wife reported a change of his character 2 weeks before. A few days previously he developed uncontrolled movements of all limbs, so that he could not walk alone. There was a history of a severe recalcitrant plaque type psoriasis, which was futilely treated …

Trans-species activation of human T cells by rhesus macaque CD1b molecules

Despite crucial importance of non-human primates as a model of human infectious diseases, group 1 CD1 genes and proteins have been poorly characterized in these species. Here, we isolated CD1A, CD1B, and CD1C cDNAs from rhesus macaque lymph nodes that encoded full-length CD1 proteins recognized specifically by monoclonal antibodies to human CD1a, CD1b, and CD1c molecules, respectively. The monkey group 1 CD1 isoforms contained amino acid residues and motifs known to be critical for intramolecular disulfide bond formation, N-linked glycosylation, and endosomal trafficking as in human group 1 CD1 molecules. Notably, monkey CD1b molecules were capable of presenting a mycobacterial glycolipid to human CD1b-restricted T cells, providing direct evidence for their antigen presentation function. This also detects for the first time a trans-species crossreaction mediated by group 1 CD1 molecules. Taken together, these results underscore substantial conservation of the group 1 CD1 system between humans and rhesus macaque monkeys.

Immunohistochemical Application of an Antibody Specific for Human CD1a to the Diagnosis of Canine Mast Cell Tumour

Canine mast cell tumours (MCTs) may be graded microscopically for prognostic purposes. Grade I (well-differentiated) and grade II (intermediate differentiation) tumours have an abundance of metachromatic granules within the cytoplasm; however, grade III (poorly differentiated) MCTs may be difficult to diagnose as they frequently have fewer discernable granules. Herein we report that a cross-reactive anti-human CD1a monoclonal antibody (clone O10) may be used in immunohistochemistry to identify canine MCTs of all grades. The antibody was applied to tissue sections from 48 canine MCTs of different histological grades. Serial sections from each tumour were stained with toluidine blue and safranin O to compare diagnostic sensitivity. All MCTs were labelled positively by the CD1a antibody, but histochemical staining was often equivocal and identification of mast cells was extremely difficult in some cases. This antibody did not label neoplastic cells in cases of canine histiocytoma, plasmacytoma or amelanotic melanoma; therefore, the reagent may be a valuable marker for the diagnosis of canine MCTs, especially those tumours of histological grade III.

Transcriptional profiling of human skin-resident Langerhans cells and CD1a+ dermal dendritic cells: differential activation states suggest distinct functions

In human skin, two main populations of dendritic cells (DC) can be discriminated: dermal DC (DDC) and epidermal Langerhans cells (LC). Although extensively studied, most of the knowledge about DDC and LC phenotype and function is obtained from studying DDC and LC cultured in vitro or DDC and LC migrated from skin explants. These studies have left the exact relationship between steady-state human LC and DDC unclear: in particular, whether CD1a+ DDC represent migrated LC or whether they constitute a separate subset. To gain further insight in the kinship between skin-resident CD1a+ DDC and LC, we analyzed CD1a+ DDC and LC, isolated from steady-state skin samples, by high-density microarray analysis. Results show that the CD1a+ DDC specifically express markers associated with DDC phenotype, such as the macrophage mannose receptor, DC-specific ICAM-grabbing nonintegrin, the scavenger receptor CD36, coagulation factor XIIIa, and chemokine receptor CCR5, whereas LC specifically express Langerin, membrane ATPase (CD39), and CCR6, all hallmarks of the LC lineage. In addition, under steady-state conditions, both DC subsets display a strikingly different activation status, indicative of distinct functional properties. CD1a+ DDC exhibit a more activated, proinflammatory, migratory, and T cell-stimulatory profile, as compared with LC, whereas LC mainly express molecules involved in cell adhesion and DC retention in the epidermis. In conclusion, transcriptional profiling is consistent with the notion that CD1a+ DDC and LC represent two distinct DC subsets but also that under steady-state conditions, CD1a+ DDC and epidermal LC represent opposites of the DC activation spectrum.

Cutting Edge: A Naturally Occurring Mutation in CD1e Impairs Lipid Antigen Presentation

The human CD1a-d proteins are plasma membrane molecules involved in the presentation of lipid Ags to T cells. In contrast, CD1e is an intracellular protein present in a soluble form in late endosomes or lysosomes and is essential for the processing of complex glycolipid Ags such as hexamannosylated phosphatidyl-myo-inositol, PIM(6). CD1e is formed by the association of beta(2)-microglobulin with an alpha-chain encoded by a polymorphic gene. We report here that one variant of CD1e with a proline at position 194, encoded by allele 4, does not assist PIM(6) presentation to CD1b-restricted specific T cells. The immunological incompetence of this CD1e variant is mainly due to inefficient assembly and poor transport of this molecule to late endosomal compartments. Although the allele 4 of CD1E is not frequent in the population, our findings suggest that homozygous individuals might display an altered immune response to complex glycolipid Ags.

Human FOXP3+ T regulatory cells suppress mouse T cell activation by targeting mouse dendritic cells via a human LFA‐1/mouse ICAM‐1 mediated interaction

We have developed a novel in vitro T suppressor cell assay in which the responders are mouse CD4+CD25‐ T cells (mCD4+) stimulated by mouse T‐depleted splenocytes and soluble anti‐mouse CD3, and the T suppressors are human CD4+FOXP3+CD25hi cells (nTreg) activated with plate‐bound anti‐human CD3/CD28. Human nTreg were almost as efficient as mouse nTreg in suppressing the responses of mCD4+ cells. Suppression was not abrogated by neutralizing human IL‐10 or TGFbeta, and was not observed when responders and suppressors were separated in a transwell. Cell contact between the human nTreg and the mouse cells was required as blocking human CD11a or CD18 completely abrogated suppression. Mouse mCD4+ cells deficient in ICAM‐1 were suppressible, suggesting that the nTreg targeted the mouse dendritic cells through the binding of human LFA‐1 with mouse ICAM‐1. Mouse nTreg could not suppress human CD4+ T cells most likely due to the fact that mouse LFA‐1 could not bind to human ICAM. Under suboptimal stimulatory conditions, hIL‐2 was required for activation of nTreg suppressor function. Since the human IL‐2R does not bind mouse IL‐2, IL‐2 consumption is ruled out as a mechanism of suppression. Our results indicate that one of the mechanisms of nTreg‐mediated suppression functions across species and that this cross‐species assay should prove to be a valuable tool for studying the mechanisms of action of human nTreg.

CD14+ antigen-presenting cells in human dermis are less mature than their CD1a+ counterparts

We recently demonstrated that three antigen-presenting cell (APC) subsets exist in the healthy human dermis, CD14(+) and CD1a(+) dermal APCs and migratory dermal Langerhans cells. Here, we extend these findings by defining CD208 as an exclusive marker of migratory dermal Langerhans cells, confirming that migratory dermal Langerhans cells (CD1a(high) CD207(+) CD208(+)) and CD1a(+) dermal APCs (CD1a(mid) CD207(-) CD208(-)) are two distinct APC populations. Using flow cytometry and multicolor fluorescence immunohistochemistry, we demonstrated that there were striking differences between CD1a(+) and CD14(+) dermal APCs in their expression of pattern recognition receptors and maturation markers. Expression of Toll-like receptor (TLR) 2, CD206 and CD209 was largely restricted to CD14(+) dermal APCs. Consistent with these observations, most CD14(+) dermal APCs expressed an immature phenotype when compared with CD1a(+) dermal APCs, which expressed high levels of the maturation marker CD83 on their cell surface. However, a subset of CD14(+) dermal APCs also expressed cell-surface CD83, associated with a loss of cell-surface TLR2, suggesting that they have the capacity to mature. CD14(+) dermal APCs are therefore the dominant cutaneous APC population capable of sensing ligands recognized by CD206, CD209 and TLR2 and subsequently may have the potential to mature. CD68 expression was largely restricted to a subset of CD14(+) dermal APCs, while both CD14(+) and CD1a(+) dermal APCs expressed CD11b and CD11c. These findings have important implications for understanding cutaneous immune responses in humans and for the optimization of vaccine delivery via the skin.

Overexpression of a hematopoietic transcriptional regulator EDAG induces myelopoiesis and suppresses lymphopoiesis in transgenic mice

Erythroid differentiation-associated gene (EDAG) is a hematopoietic tissue-specific gene that is highly expressed in the earliest CD34+ lin- bone marrow (BM) cells and involved in the proliferation and differentiation of hematopoietic cells. To investigate the role of EDAG in hematopoiesis, we established an EDAG transgenic mouse model driven by human CD11a promoter. The transgenic mice showed increased mortality with severe organ infiltration by neutrophils, and the homeostasis of hematopoiesis was broken. The myelopoiesis was enhanced with expansion of myeloid cells in BM, increased peripheral granulocytes and extramedullary myelopoiesis in spleen. In contrast to myeloid cells, the lymphoid commitment was severely impaired with the B lymphopoiesis blocked at the transition from pro/pre-B I to pre-B II stage in BM and T thymocytes development blocked at the most immature stage (DN I). Moreover, we showed that EDAG was a transcriptional regulator which had transactivation activity and regulated the expression of several key transcription factors such as PU.1 and Pax5 in transgenic hematopoietic stem cells. These data suggested that EDAG was a key transcriptional regulator in maintaining the homeostasis of hematopoietic lineage commitment.

CD8 Raft Localization Is Induced by Its Assembly into CD8αβ Heterodimers, Not CD8αα Homodimers

The coreceptor CD8 is expressed as a CD8alphabeta heterodimer on major histocompatibility complex class I-restricted TCRalphabeta T cells, and as a CD8alphaalpha homodimer on subsets of memory T cells, intraepithelial lymphocytes, natural killer cells, and dendritic cells. Although the role of CD8alphaalpha is not well understood, it is increasingly clear that this protein is not a functional homologue of CD8alphabeta. On major histocompatibility complex class I-restricted T cells, CD8alphabeta is a more efficient TCR coreceptor than CD8alphaalpha. This property has for the mouse protein been attributed to the recruitment of CD8alphabeta into lipid rafts, which is dependent on CD8beta palmitoylation. Here, these divergent distributions of CD8alphabeta and CD8alphaalpha are demonstrated for the human CD8 proteins as well. However, although palmitoylation of both CD8alpha and CD8beta chains was detected, this modification did not contribute to raft localization. In contrast, arginines in the cytoplasmic domain are crucial for raft localization of CD8betabeta. Most strikingly, the assembly of a non-raft localized CD8beta chain with a non-raft localized CD8alpha chain resulted in raft-localized CD8alphabeta heterodimers. Using chimeric CD8 proteins, this property of the heterodimer was found to be determined by the assembly of CD8alpha and CD8beta extracellular regions. The presence of two CD8alpha extracellular regions, on the other hand, appears to preclude raft localization. Thus, heterodimer formation and raft association are intimately linked for CD8alphabeta. These results emphasize that lipid raft localization is a key feature of human CD8alphabeta that clearly distinguishes it from CD8alphaalpha.

CD1a and CD1e Allele Frequencies in an Italian Population from the Abruzzo Region

CD1 is a small family comprising 5 MHC-like genes located on chromosome 1 and encoding glycoproteins termed CD1a, CD1b, CD1c, CD1d and CD1e. They are expressed mainly on the surface of dendritic cells, monocytes and some thymocytes and are specialized in presenting lipid antigens to T lymphocytes. The structure is similar to that of MHC class I molecules with 3 globular domains and the Beta2-microglobulin. It has been shown that all five human CD1 genes exhibit a limited number of polymorphisms in the alpha1 domain whose effects are still unknown. CD1e results to be the most polymorphic isoform with six CD1e alleles (01, 02 in exon 2 and 03, 04, 05, 06 in ex3) described to date. At this moment, few investigations on the allele frequencies of the CD1 genes have been reported and all additional information improves our knowledge on this new class of antigen-presenting molecules. In order to study possible allelic variations of exon 2 of human CD1a and CD1e genes, we analyzed, by a sensitive technique, the sequence-based typing (SBT), 114 DNA samples from unrelated healthy Italian individuals from the Abruzzo region. Our experimental findings indicate that the allele frequency distribution of both CD1a and CD1e genes is in accordance with that observed in other geographic areas and did not identify any new allele, thus confirming a very low polymorphism.

Characterization of antigen‐presenting cells in human apical periodontitis lesions by flow cytometry and immunocytochemistry

To analyse phenotypic characteristics of antigen-presenting cells (APC), isolated from human periapical lesions by flow cytometry and immunocytochemistry. Sixteen periapical lesions were digested for 15 min with 0.05% collagenase. Mononuclear cells, separated from other inflammatory cells by density centrifugation, were processed for flow cytometry and/or immunocytochemistry. Single and double immunostainings were performed using monoclonal antibodies specific for human CD45, CD3, CD19, CD14, HLA-DR, CD1a, CD83 and CD123. Antigen-presenting cells (HLA-DR(+) cells) represented 32.9 +/- 17.8% of total mononuclear cells. Amongst them, B cells (HLA-DR(+) CD19(+)) were the predominant APC population, followed by activated macrophages (HLA-DR(+) CD14(+)), dendritic cells (DC) (HLA-DR(+) CD14(-) CD19(-) CD3(-)) and activated T cells (HLA-DR(+) CD3(+)). Based on the predominance of T cells (CD3(+)) or B cells and plasma cells (CD19(+) and CD19(lo), respectively) amongst mononuclear cell infiltrates, lesions were divided into T- and B-types. The percentage of DC in T-type lesions (27.1 +/- 6.8% of total HLA-DR(+) cells) was higher, compared with B-type lesions (10.3 +/- 5.2%) (P < 0.01). Within the DC population, the percentages of CD1a (Langerhans cell type) and CD123 (probably plasmacytoid DC type) did not differ significantly between the groups (P > 0.05). However, the percentage of mature DC (CD83(+)) was significantly higher in T-type periapical lesions (P < 0.05). Flow cytometry and immunocytochemistry are suitable methods for phenotypic analysis of APC after their isolation from human periapical lesions. APC, that were phenotypically heterogeneous, constituted a significant component of infiltrating cells. Lesions with the predominance of T cells were characterized by a higher proportion of mature DC (HLA-DR(+)CD83(+) cells) than lesions with predominance of B cells/plasma cells.

The Bovine CD1 Family Contains Group 1 CD1 Proteins, but No Functional CD1d

The CD1 family of proteins presents lipid Ags to T cells. Human CD1a, CD1b, and CD1c have been shown in humans to present mycobacterial lipid Ags. Cattle, like humans, are a natural host of several mycobacterial pathogens. In this study, we describe the CD1 family of genes in cattle (Bos taurus) and provide evidence that B. taurus expresses CD1a, CD1e, and multiple CD1b molecules, but no CD1c and CD1d molecules. In mice and humans, CD1d is known to present Ag to NKT cells, a T cell lineage that is characterized by a limited TCR repertoire, capable of rapidly secreting large amounts of IFN-gamma and IL-4. In cattle, two CD1D pseudogenes were found and no intact CD1D genes. Consistent with this, we found complete lack of reactivity to a potent, cross-reactive Ag for NKT cells in mice and humans, alpha-galactosylceramide. Our data suggest the absence of NKT cells in cattle. It remains open whether other cells with the NKT-like phenotype and functions are present in this species. With its functional CD1A and CD1B genes, B. taurus is well equipped to present Ags to CD1-restricted T cells other than NKT cells. Cattle can be used as a model to study group 1 CD1-restricted T cell immunity, including its role in the defense against mycobacterial infections that occur naturally in this species.