Reduced Frequency of Memory T Cells and Increased Th17 Responses in Patients with Active Tuberculosis

Phenotypic and functional alterations in Mycobacterium tuberculosis T cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, the ex vivo phenotype of CD4⁺ and CD8⁺ T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4⁺ CD45RO⁺ CD27⁺ T cells and an increased frequency of CD4⁺ CD45RO⁻ CD27⁺ T cells. ATB also had a higher frequency of circulating IL-17-producing CD4⁺ T cells than did LTBi after PPD stimulation, whereas LTBi had more IFN-γ-producing CD4⁺ T cells than did non-TBi. The phenotype of IFN-γ-producing cells at 24 h differs from the phenotype of IL-17-producing cells with no differences between LTBi and ATB. At 144 h, IFN-γ- and IL-17-producing cells were mainly CD45RO⁺ CD27⁺ T cells and they were more frequent in ATB. These results suggest that M. tuberculosis infection induces alterations in T cells which interfere with an adequate specific immune response.     

Regulation of neuroinflammation by B cells and plasma cells

The remarkable success of anti‐CD20 B cell depletion therapies in reducing the burden of multiple sclerosis (MS) disease has prompted significant interest in how B cells contribute to neuroinflammation. Most focus has been on identifying pathogenic CD20⁺ B cells. However, an increasing number of studies have also identified regulatory functions of B lineage cells, particularly the production of IL‐10, as being associated with disease remission in anti‐CD20–treated MS patients. Moreover, IL‐10–producing B cells have been linked to the attenuation of inflammation in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. In addition to IL‐10–producing B cells, antibody‐producing plasma cells (PCs) have also been implicated in suppressing neuroinflammation. This review will examine regulatory roles for B cells and PCs in MS and EAE. In addition, we speculate on the involvement of regulatory PCs and the cytokine BAFF in the context of anti‐CD20 treatment. Lastly, we explore how the microbiota could influence anti‐inflammatory B cell behavior. A better understanding of the contributions of different B cell subsets to the regulation of neuroinflammation, and factors that impact the development, maintenance, and migration of such subsets, will be important for rationalizing next‐generation B cell–directed therapies for the treatment of MS.     

Human rotavirus specific T cells: quantification by ELISPOT and expression of homing receptors on CD4+ T cells

Using an intracellular cytokine assay, we recently showed that the frequencies of rotavirus (RV)-specific CD4(+) and CD8(+) T cells secreting INFgamma, circulating in RV infected and healthy adults, are very low compared to the frequencies of circulating cytomegalovirus (CMV) reactive T cells in comparable individuals. In children with acute RV infection, these T cells were barely or not detectable. In the present study, an ELISPOT assay enabled detection of circulating RV-specific INFgamma-secreting cells in children with RV diarrhea but not in children with non-RV diarrhea without evidence of a previous RV infection. Using microbead-enriched CD4(+) and CD8(+) T cell subsets, IFNgamma-secreting RV-specific CD8(+) but not CD4(+) T cells were detected in recently infected children. Using the same approach, both CD4(+) and CD8(+) RV-specific T cells were detected in healthy adults. Furthermore, stimulation of purified subsets of PBMC that express lymphocyte homing receptors demonstrated that RV-specific INFgamma-secreting CD4(+) T cells from adult volunteers preferentially express the intestinal homing receptor alpha4beta7, but not the peripheral lymph node homing receptor L-selectin. In contrast, CMV-specific INFgamma-secreting CD4(+) T cells preferentially express L-selectin but not alpha4beta7. These results suggest that the expression of homing receptors on virus-specific T cells depends on the organ where these cells were originally stimulated and that their capacity to secrete INFgamma is independent of the expression of these homing receptors.     

High dimensional analysis reveals distinct NK cell subsets but conserved response to stimulation in umbilical cord blood and adult peripheral blood

Growing interest surrounds adoptive cellular therapies utilizing Natural Killer (NK) cells, which can be obtained from various sources, including umbilical cord blood (UCB) and adult peripheral blood (APB). Understanding NK cell receptor expression and diversity in such cellular sources will guide future therapeutic designs. We used a 20-color flow cytometry panel to compare unstimulated and cytokine-activated UCB and APB NK cells. Our analysis showed that UCB NK cells express slightly higher levels of the immune checkpoints PD-1, TIGIT, and CD96 compared to their APB counterparts. Unsupervised hierarchical clustering and dimensionality reduction analyses revealed enrichment in CD56^neg as well as mature NKp46^neg and CD56⁺CD16⁺ NK cell populations in UCB whereas CD57⁺ terminally differentiated NK cells with variable expression of KIRs and CD16 were found in APB. These populations were conserved following stimulation with IL-12, IL-15, and IL-18. Cytokine stimulation was associated with the downregulation of TIGIT and CD16 on multiple NK cell subsets in UCB and APB. Among UCB CD16⁻ NK cell populations, TIGIT⁺ NK cells produced more IFN-γ than their TIGIT⁻ counterparts. Our data demonstrate higher immune checkpoint expression on UCB NK cells compared to APB. However, the expression of TIGIT immune checkpoint is not indicative of NK cell exhaustion.     

Identification of two nonglycosylated polypeptides of Taenia solium recognized by immunoglobulins from patients with neurocysticercosis

An immunoprecipitation technique using biotin-labeled proteins of Taenia solium was developed to identify antigens recognized by immunoglobulins from patients with neurocysticercosis. Six major polypeptides of 100, 70, 50, 42, 35, and 24 kDa were recognized by cerebrospinal fluid from most serologically positive patients. All polypeptides except the 70- and 35-kDa antigens were retained on a lentil-lectin chromatography column and were recognized by lentil lectin in an overlay assay. The 70- and 35-kDa antigens were not labeled with biotin hydrazide, indicating that saccharide residues are not present in these two polypeptides. Furthermore, the 70- and 35-kDa antigens were recognized by antibodies of more than 86% of patients serologically positive for neurocysticercosis as opposed to none of the patients afflicted with other neuropathologies of the central nervous system. This finding indicates that immunodiagnosis of neurocysticercosis can be carried out with antigens different from those used in the standard enzyme-linked immunoelectrotransfer assay. Received: 28 September 1998 / Accepted 15 December 1998     

Depolymerisation and rearrangement of actin filaments during exocytosis in rat peritoneal mast cells: involvement of ryanodine-sensitive calcium stores

Cytoskeletal F-actin associated with synaptic vesicles and granules plays an important role during Ca²⁺-mediated exocytosis. In the present work, we have used amperometry and confocal fluorescence to study the role of internal Ca²⁺ in the rearrangement of F-actin (visualised with phalloidin-Alexa 546) during exocytosis in rat mast cells. The F-actin-depolymerising drug, latrunculin A, and the ryanodine receptor agonists ryanodine and caffeine that, per se did not induce exocytosis, enhanced the exocytotic responses elicited by compound 48/80 (C48/80). They also induced cortical actin depolymerisation in the presence or absence of external Ca²⁺. Degranulation induced by C48/80 was accompanied by the formation of a cytoplasmic F-actin network. Depletion of internal Ca²⁺ with cyclopiazonic acid inhibited latrunculin potentiation of C48/80-stimulated exocytosis and completely blocked the formation of the cytoplasmic F-actin network. This indicates that the mobilisation of Ca²⁺ from ryanodine-sensitive intracellular stores plays an important role in the depolymerisation of the cortical F-actin barrier and possibly in the formation of the internal F-actin network during exocytotic activation of peritoneal mast cells.     

Currant allergy and the Rosaceae-grass pollen allergy syndrome: a case report.

BACKGROUND: Despite the increasing use of currants in culinary recipes, currant allergy has rarely been reported. OBJECTIVES: To study a case of currant allergy and to explore cross-reactivity between grass pollen and Rosaceae family fruit allergens. METHODS: Skin prick tests to pollen and skin prick-to-prick tests with currants and peach were performed. Specific IgE levels were determined using the CAP method. We prepared a protein extract of 0.1 mg/mL in phosphate-buffered saline using red currant in the presence of protease inhibitors. Immunoblot inhibition studies were performed to explore cross-reactivity between grass pollen and currant allergens. RESULTS: Skin prick test results were positive to Dactylis, arizonic, and olive pollens. Results of skin prick-to-prick tests with fresh red and black currants were negative and positive, respectively, to peach. The specific IgE level was 5.7 KU/L to red currant and 2.92 KU/L to peach (CAP). Western blot analysis with red currant extract revealed specific IgE protein bands of 37 and 26 kDa. Preincubation of sera with extracts from red currant and peach inhibited both IgE bands, and preincubation with Dactylis pollen inhibited the 37-kDa band only. CONCLUSIONS: We report a case of allergy to grass pollen with an oral allergy syndrome involving several fruits from 2 different families of the Rosidae subclass confirmed by in vitro tests. Inhibition studies demonstrated cross-reactivity between different fruits (currant and raspberry) from the Rosidae subclass and were incomplete with grass pollen allergens.     

Effect of the COX-2 Selective Inhibitor L-745,337 on Inflammation and Organ Prostaglandin E2 (PGE2) Levels in Adjuvant Arthritic Rats

The anti-inflammatory activity of the cyclooxygenase-2 inhibitor, L745,337, was assessed in adjuvant arthritic rats (AA). The relationship between PGE₂ organ levels and drug activity or adverse effects was determined. Arthritic rats were orally treated for two weeks with L-745,337 (0.1, 1 and 5 mg/kg/day), indomethacin (1 mg/kg/day) or vehicle and paw swelling was determined. At the end of the study, samples from paw, stomach (wall and mucosa) and kidney were obtained from rats with or without treatment at high doses of L-745,337 or indomethacin and PGE₂ levels were determined. The L-745,337 anti-inflammatory effective-dose-50 was 0.4 mg/kg. Maximal anti-inflammation was obtained with L-745,337 or indomethacin at doses of 5 and 1 mg/kg respectively. L-745,337 showed anti-arthritic activity. No stomach ulcers appeared in either untreated or treated arthritic and healthy control rats. In AA rats, PGE₂ increased in paw, stomach wall, gastric mucosa and kidney. These levels were lower in all organs after both drugs but not below PGE₂ control levels.     

Analysis of the Cycilin D1/p16/pRb Pathway in Parathyroid Adenomas

Cyclin D1/p16/pRb pathway controlling G1→S cell cycle checkpoint is frequently altered in human tumors. Currently, scarce data are available for parathyroid tumors. We have studied 46 parathyroid adenomas (PTAs) and 12 normal parathyroid glands (PTGs) by immunohistochemistry with cyclin D1 (CD1), p16, pRb, and Ki-67 antibodies. We observed CD1 expression in 89%, p16 in 70%, and pRb in 100% of PTAs. Statistically significant differences with normal PTGs were found only concerning p16 expression (p<0.05). Proliferating rate (Ki-67) was always low, although significantly higher than in normal PTGs. Our findings demonstrate the presence of alterations in the CD1/p16/pRb pathway in PTAs, consisting in p16 overexpression apparently unrelated to pRb downregulation. On the other hand, we did not find significant differences in CD1 expression between PTAs and normal PTGs, suggesting CD1 overexpression could be a physiological event in parathyroid tissue.