Antigen-specific suppression of cultured lymphocytes from patients with neurocysticercosis

ATaenia crassicepsfactor induces apoptosis of spleen CD4+T cells and TFG-β andFoxp3gene expression in mice

This study was undertaken to determine whether a parasite substance produces structural pathology in the mouse spleen. A low-molecular-weightTaenia crassicepsmetacestode factor (MF) isolated from the peritoneal fluid of female mice infected withT. crassicepsmetacestodes induced pathological and immunological changes in mouse spleen cellsin vivo.Electron microscopy and confocal microscopy revealed severe changes in the spleen histoarchitecture ofT. crassiceps-infected and MF-treated mice. Apoptotic degenerated spleen cells were observed in the white and red pulps and were more conspicuous in the white pulp of the spleen from theT. crassiceps-infected mice than in that of the MF-treated mice. Flow cytometry analysis revealed that the numbers of spleen CD4+T cells were significantly lower in both experimental groups than in control mice. Theex vivoexpression of transforming growth factor (TGF)-β and factor Foxp3 were significantly higher in splenocytes of the experimental mice than the basal expression observed in the control cells. These findings may have potential applications for a better understanding of the host–parasite relationship in human neurocysticercosis.

Neurocysticercosis: local and systemic immune-inflammatory features related to severity

Neurocysticercosis (NC) is caused by the establishment of Taenia solium cysticerci in the central nervous system. Previous studies have established that neuroinflammation plays a key role in the severity of the disease. However, the relationship between peripheral and local immune response remains inconclusive. This work studies the peripheral and local immune-inflammatory features and their relationships, toward the identification of potential peripheral immunologic features related to severity. A panel of cytokines was measured in paired cerebrospinal fluid (CSF) and in the supernatant of antigen-specific stimulated peripheral blood mononuclear cells samples (SN) in a total of 31 untreated inflammatory and non-inflammatory NC patients. Increased clinical and radiologic severity was associated with an increased cerebrospinal fluid cell count. A peripheral proliferative depression that negatively correlates with CSF cellularity and TNFα and that positively correlates with SN IL5 was observed in severe NC patients. These results provide evidences to support the systemic proliferative response as a biomarker to monitor the level of neuroinflammation, of possible value in the patients' follow-up during treatment.

Immune response to different fractions of Taenia solium cyst fluid antigens in patients with neurocysticercosis

The immunopathogenesis of neurocysticercosis (NCC) largely remains unknown. We analyzed the immune response to different fractions of Taenia solium cyst fluid antigens in patients with NCC. Lymphocytes were separated from 48 patients with NCC-related active epilepsy and 30 healthy controls. T. solium (isolated from pig muscles) antigens (crude lysate, CL; cyst wall, CW and cyst fluid, CF) at 20 μg/well concentrations were used to stimulate the cells in a lymphocyte transformation test (LTT). Only CF antigen stimulated cell proliferation significantly greater than control (p<0.001), hence cyst fluid antigens were further studied. The CF antigens were electro-blotted on nitrocellulose membrane (NC), cut at 0.5 cm distance and particulate antigens were prepared. A total of 12 fractions, designated F1 to F12 according to molecular weight were tested in-vitro for LTT. After 72 h of stimulation by the different fractions, Th1 (IL-1β, TNF-α, IL-2) and Th2 (IL-4, IL-10) cytokine responses were determined in culture supernatants by ELISA. Low molecular weight fractions F1 through F4 (Mol. wt.<25 kDa) were found to be potent inducers of cytokines. Fractions F1, F3 and F4 induced the production of Th1 (IL-1β, TNF-α, IL-2), whereas F2 induced the production of Th2 (IL-4 and IL-10) cytokine. The study shows that the low molecular weight fractions of CF antigens are immuno-dominant. Most of these fractions (F1, F3, F4) induce strong Th1 immune response except F2 which induces Th2 response. Further studies are needed to identify the different antigens present in these fractions to determine the molecules responsible for the immune response.

Mechanisms regulating monocyte CXCL8 secretion in neurocysticercosis and the effect of antiparasitic therapy

Neurocysticercosis (NCC) due to infection with Taenia solium is a major cause of epilepsy worldwide. Larval degeneration, which may follow antiparasitic treatment, results in clinical symptoms due to inflammatory cell influx. Mechanisms regulating this are not well understood, but chemokines have a key role. Stimulation of human monocytes by cyst Ags from NCC-infected pigs showed that scolex and membrane Ags drive CXCL8 and CCL2 secretion. Antiparasitic treatment of pigs increased CXCL8 in response to brain, but not muscle, cyst Ags. Cyst-fluid Ags did not elicit monocyte chemokine secretion, inhibited LPS-induced CXCL8 by up to 89%, but did not alter CCL2 secretion. This effect was inhibited by anti-IL-10 Abs. Plasma CXCL8, TNF-α, IL-10, eotaxin, IL-1, IL-1ra, soluble IL-1R-II, and soluble TNFR-I and -II levels were evaluated in 167 NCC patients. Patients had lower plasma CXCL8 and TNF-α concentrations than control subjects. In summary, larval Ags from brain and muscle cysts differentially regulate chemokine secretion. Cyst-fluid inhibits CXCL8, and this is blocked by anti-IL-10 Abs. CXCL8 concentrations are decreased in patient plasma. Following anti-parasitic therapy, scolex and membrane Ags are exposed, and cyst fluid is decreased, leading to inflammatory cell influx. Taken together, the cellular, porcine, and human data may explain, in part, why NCC is usually asymptomatic but may cause proinflammatory symptoms, particularly following treatment.

The immune response in Taenia solium cysticercosis: protection and injury

This article reviews current knowledge on the innate and acquired immune responses in human Taenia solium neurocysticercosis, highlighting the conditions that appear to be favourable for the survival or destruction of the parasite and for the benefit or injury to its host.

A depressed peripheral cellular immune response is related to symptomatic neurocysticercosis

Human neurocysticercosis can cause mild or severe neurological symptoms or be completely asymptomatic. This heterogeneity may depend on host factors such as gender, age and immune-inflammatory response. The present study describes the specific peripheral immune response related to the different forms of neurocysticercosis in the adult population of both sexes. Asymptomatic cases (n = 26) mainly presented single calcified cysticerci in brain parenchyma or in the subarachnoid space of the sulci with a predominantly TH2 response (IL-4, IL-5, IL-13), high levels of IL-12 in supernatants of specifically stimulated peripheral blood mononuclear cells, and low plasma levels of all specific IgG subclasses. Symptomatic patients (n = 26) constituted a heterogeneous group, and had single or multiple cysticerci in vesicular, colloidal, calcified or mixed stages. This group showed parasites located in the subarachnoid space of the base and/or in the sulci, in the ventricular cavities, in parenchyma or in mixed locations. Symptomatic patients showed a depressed specific cellular immune response and increased levels of all specific IgG subclasses. This evidence supports the existence of two clear different immune profiles according to neurocysticercosis that is asymptomatic or symptomatic.

Cysticercosis immunodiagnosis using 18- and 14-kilodalton proteins from Taenia crassiceps cysticercus antigens obtained by immunoaffinity chromatography

Monoclonal antibodies (MAb) against Taenia crassiceps and Taenia solium cysticerci were produced and showed cross-reactivity with a 14-kDa protein from T. solium and with 18- and 14-kDa proteins from T. crassiceps. These MAbs and antibodies from cerebrospinal fluid (CSF) as well as serum samples from patients with neurocysticercosis (NC) reacted with 18- and 14-kDa T. crassiceps proteins purified by immunoaffinity chromatography using a Sepharose column coupled with MAbs (anti-excretory/secretory or anti-vesicular fluid antigens). Immunoaffinity-purified 18- and 14-kDa proteins were used in the design of a diagnostic enzyme-linked immunosorbent assay (ELISA) to detect antibodies in 23 CSF and 20 serum samples from patients with NC, showing 100% sensitivity. The test specificity was determined using 42 noninflammatory CSF samples and 70 inflammatory CSF samples from patients with other neurological disorders (OND), showing 100% and 99.1% (confidence interval, 97.3% to 100%) specificity, respectively. A false-positive CSF sample result in the OND group was from a human immunodeficiency virus-positive patient with meningoencephalitis. By using serum samples from 194 healthy individuals, the specificity was 100%. Analysis of an additional 16 serum samples from individuals with other parasitic diseases (13 with intestinal parasitosis and 3 with schistosomiasis) showed negative results. Three (10%) serum samples from patients with hydatidosis were positive in our ELISA and in ELISA with T. solium cysticerci antigens. Two of them were also positive by immunoblotting. The use of 18- and 14-kDa T. crassiceps immunoaffinity-purified proteins for detection of anti-cysticercus antibodies in CSF and/or serum samples using an ELISA system showed a good performance and high specificity for serum samples, dispensing with the use of confirmatory tests, such as immunoblotting, for checking specificity.

The implantation of Taenia solium metacestodes in mice induces down-modulation of T-cell proliferation and cytokine production

The purpose of this study was to determine the effect of the implantation of Taenia solium metacestodes and the treatment with suppressive metacestode factor (F1) on the ability of spleen cells from Balb/c mice to produce cytokines. Cytokine production was estimated 12 days following the implantation or 4 days after the last dose of F1 (five doses) by RT-PCR and flow cytometry analyses. Spleen cells were obtained from metacestode-implanted, F1-treated and control mice. They were stimulated with concanavalin A (ConA) ex vivo and used for RT-PCR studies and for CD25 expression and intracellular cytokine production estimations using specific monoclonal antibodies labeled with phycoerithrin or fluorescein. Results of the RT-PCR showed that all cells expressed IFN-gamma, IL-2 and IL-4 mRNAs. IL-10 mRNA was not expressed in any case. Flow cytometry analyses showed that both spleen CD4+ and CD8+ cells from metacestode-implanted or treated-F1 mice expressed significantly diminished percentages of CD25 when compared with control cells (P<0.05). The estimation of intracellular cytokines showed that the production of IL-2 and IL-4 in CD8+ cells, and of IFN-gamma in CD4+ cells from mice implanted with metacestodes was significantly impaired when compared with the values from control cells (P<0.05).

Cellular immune response of patients with neurocysticercosis (inflammatory and non-inflammatory phases)

The cellular immune response in neurocysticercosis (NC) was studied in 22 patients, 11 (50%) of them in the inflammatory phase of the disease, by means of immunophenotyping of cells in cerebrospinal fluid (CSF) and peripheral blood (PB), lymphoproliferation assay with Taenia solium total saline extract (Tso) and Taenia crassiceps vesicular fluid (Tcra) as stimuli, and by determining the cytokine production profile in the cell culture supernatant. A higher mean percentage of CD19+ and CD56+ cells was observed in the CSF samples from inflammatory (16.8 and 11.3%) and non-inflammatory NC-patients (14.1 and 8.4%) when compared with the control group (CG, 7.6 and 5.4%). The CSF samples from inflammatory NC-patients also showed a higher percentage of HCAM (19.1%) and ICAM (44.9%) adhesion molecules when compared to CG (3.1 and 4.8%). The inflammatory phase showed predominance of CD8+ cells (CSF 26.6% and PB 36.2%) when compared with non-inflammatory phase (CSF 21.5% and PB 29.0%). All cell populations identified in the CSF from NC-patients showed cell activation (CD69+). The cell populations identified in PB showed higher expression of CD69 during the inflammatory phase, while only CD4+ cells presented no cell activation during the non-inflammatory phase. The antigen-specific lymphoproliferation assay showed mean positive results (stimulation index, SI > or = 2.5) only for cells from inflammatory NC-patients (Tcra 3.2 and Tso 5.4), but less intense than the CG (Tcra 5.7 and Tso 8.9). The cytokine production profile when using Tso antigen as stimuli showed differences between NC-patients with inflammatory (production of IL-4/IL-12/TNF-alpha/ICAM/VCAM) and non-inflammatory phase (production of IL-6/IL-10/IL-12/TNF-alpha/ICAM/VCAM). A prevalence of Th2 profile was observed in nine (69%) of the 13 (62% of total) NC-patients presenting positive SI. Cells from inflammatory NC-patients showed a predominance of a Th1 response upon in vitro stimulation, while those from non-inflammatory NC-patients showed a mixed Th1/Th2 pattern.