Prevalence of Sarcocystis neurona and Neospora spp. infection in horses from Brazil based on presence of serum antibodies to parasite surface antigen

Sera from 961 horses from Brazil were tested for antibodies against the major surface antigens SnSAG4 and NhSAG1 to determine the seroprevalence of Sarcocystis neurona and Neospora hughesi, respectively. Antibodies against SnSAG4 were detected in 669 (69.6%) of the horses, while antibodies against NhSAG1 were detected in only 24 (2.5%) of the horses. These serologic results suggest that there is a high concentration of S. neurona in the environment of Brazil, which results in marked exposure of horses to this parasite. Additionally, the data further confirm that infection with Neospora spp. is relatively uncommon in horses. (c) 2005 Elsevier B.V. All tights reserved.

Immunodiagnosis of swine cysticercosis by indirect ELISA employing a heterologous antigen from Taenia crassiceps metacestode

C. Larralde et al. (1990, Arch. Pathol. Lab. Med., 114:926-928) demonstrated that heterologous antigen from the laboratory-adapted murine Taenia crassiceps metacestode may substitute those from Taenia solium in the immunodiagnosis of human cysticercosis by the indirect enzyme-linked immunosorbent assay (IE). ?This antigen is easily obtained at a laboratory level and solves the problem of T. solium cysticerci collection from naturally or experimentally infected swine. In this study an IE employing a heterologous antigen from the T. crassiceps metacestode was evaluated for the immunodiagnosis of swine cysticercosis. Sera from 300 swine free of T. solium cysticerci by post-mortem examination were employed to determine two IE cut- off values: 1) Mean ELISA values + 2 standard deviations (2 sigma cut-off) and 2) - Mean ELISA values + 3 standard deviations (3 sigma cut-off). The specificity of IE was 97% with the 2 sigma cut-off and 100% with the 3 sigma cut-off. When applied to ten sera from swine infected by cysticerci of T. solium by post-mortem examination, the sensitivity of IE was 100% independent of the cut off.

DETECTION OF CELLULAR-IMMUNITY WITH THE SOLUBLE-ANTIGEN OF THE FUNGUS SPOROTHRIX-SCHENCKII IN THE SYSTEMIC FORM OF THE DISEASE

Sporothrix schenckii is the etiologic agent of sporotrichosis, a mycosis of world-wide distribution more commonly occurring in tropical regions. The immunological mechanisms involved in the prevention and control of sporotrichosis are not fully understood but apparently include both the humoral and cellular responses. In the present investigation, cellular immunity was evaluated by in vivo and in vitro tests in mice infected with yeast-like forms of S. schenckii. The disease developed systemically and cellular immunity was evaluated for a period of 10 weeks. The soluble antigen utilized in the tests was prepared from yeast form of the fungus through the sonication (20 min: 10 sonications at 50 W at 2-min intervals). Delayed hypersensitivity and lymphocyte transformation tests showed that the cellular immune response was depressed between the 4th and 6th week of infection when the animals were challenged with the soluble fungal antigen. This depression frequently indicates worsening of the disease, with greater involvement of the host. This is a promising field of research for a better understanding of the pathogeny of this mycosis.

Estimation of growth fraction in fine needle aspirates from non-Hodgkin's lymphoma using anti-proliferating cell nuclear antigen - Correlation with the Kiel classification

OBJECTIVE: This study was undertaken to assess whether fine needle aspirates from non-Hodgkins lymphoma (NHL) could be used for growth fraction analysis with proliferating cell nuclear antigen (PCNA) staining and if there was a relationship between the growth fraction and cytomorphologic classification according to the Kiel classification.STUDY DESIGN: the study group consisted of 40 patients with NHL diagnosed by fine needle aspiration (FNA) cytology. The cytologic classification of the lymphomas was made by two cytopathologists on May-Grunwald-Giemsa-stained slides using the Kiel classification. There were 27 cases of low and 13 of high grade lymphoma. The estimation of the growth fraction was made by PCNA immunoreactivity. The PCNA index was quantitated in smears by counting an average of 1,000 cells, and the count teas correlated with the cytomorphologic classification.RESULTS: There was It strong correlation between the PCNA index and lymphoma grading. High grade lymphomas exhibited a mean PCNA positivity of 74.0%, which was significantly higher (P <.001) than that of low grade lymphomas (17.6%).CONCLUSION: Our study showed that PCNA evalua tion is suitable for smears obtained by FNA on NHL, correlates with increasing grades of lymphoma according to the Kiel classification and may offer a method of monitoring treatment of lymphoma.

Differential regulation of the release of tumor necrosis factor-alpha and of eicosanoids by mast cells in rat airways after antigen challenge

Background: Rat trachea display a differential topographical distribution of connective tissue mast cells (CTMC) and mucosal mast cells (MMC) that may imply regional differences in the release of allergic mediators such as tumor necrosis factor-alpha (TNF-alpha) and eicosanoids.Aim: To evaluate the role of CTMC and MMC for release of TNF-alpha and eicosanoids after allergenic challenge in distinct segments of rat trachea.Materials and methods: Proximal trachea ( PT) and distal trachea (DT) from ovalbumin (OVA)-sensitized rats, treated or not with compound 48/80 ( 48/80) or dexamethasone, were incubated in culture medium. After OVA challenge, aliquots were collected to study release of TNF-alpha and eicosanoids.Results: Release of TNF-alpha by PT upon OVA challenge peaked at 90 min and decayed at 6 and 24 h. Release from DT peaked at 30-90 min and decayed 6 and 24 h later. When CTMC were depleted with 48/80, OVA challenge exacerbated the TNF-alpha release by PT at all time intervals, while DT exacerbated TNF-alpha levels 6 and 24 h later only. Dexamethasone reduced TNF-alpha production after 90 min of OVA challenge in PT and at 3 and 6h in DT. OVA challenge increased prostaglandin D-2 in DT and leukotriene B-4 in both segments but did not modify prostaglandin E-2 and leukotriene C-4 release.Conclusion: OVA challenge induces TNF-alpha release from MMC, which is negatively regulated by CTMC. The profile of TNF-alpha and eicosanoids depends on the time after OVA challenge and of the tracheal segment considered.

Spectrum of carcinoembryonic antigen immunoreactivity from isolated ductal hyperplasias to atypical hyperplasias associated with infiltrating ductal breast cancer

Aims - To study the immunohistochemical expression of carcinoembryonic antigen (CEA) in ductal hyperplasia of the breast and to investigate its putative relation with atypia and co-existing infiltrating ductal carcinoma.Methods - Paraffin wax embedded tissue from 37 cases of isolated ductal hyperplasia (five with atypia and 32 without atypia) and 25 cases of ductal hyperplasia associated infiltrating ductal carcinoma (IDC) (seven with atypia and 18 without atypia) was stained with a monoclonal anti-CEA antibody using a standard avidin biotin immunoperoxidase method.Results - CEA immunoreactivity was observed in eight (12.8%) ductal hyperplasia cases. The percentage of CEA positivity in ductal hyperplasia cases with atypia (33.3%) was substantially higher than that observed in cases of ductal hyperplasia without atypia (8.0%). Six cases of ductal hyperplasia associated IDC reacted with CEA; in these six cases the neoplastic cells of the co-existing carcinoma were also CEA positive. The percentage of CEA immunoreactivity in ductal hyperplasia associated IDC was higher than that observed in isolated ductal hyperplasia (24.0 v 5.4%). The percentage of CEA immunoreactivity in atypical ductal hyperplasia associated IDC was similar to that observed in IDC alone (42.9 v 40.0%).Conclusions-The presence of CEA immunoreactivity has been confirmed in benign proliferative breast lesions. The prevalence of such immunoreactivity increases from 3.1% in isolated, nonatypical ductal hyperplasia to 42.9% in atypical ductal hyperplasia associated IDC. This finding and the similarity of the frequency of CEA positivity in atypical ductal hyperplasia associated IDC and in IDC alone suggests that there is a pathogenetic link between ductal hyperplasia and some types of breast cancer.

The proliferating cell nuclear antigen index in breast carcinomas does not correlate with mitotic index and estrogen receptor immunoreactivity

To investigate the expression of a marker of cell proliferation (PCNA/Cyclin) and its putative relationship with histological grading, mitotic index and estrogen receptor immunoreactivity, we studied twenty-seven cases of invasive breast carcinoma in formalin-fixed, paraffin-embedded tissue sections. The PCNA and estrogen receptor were detected by the PC10 and H222 monoclonal antibodies respectively, using an avidin-biotin-pernxidase method. The median value of PCNA index was 20.9% with a range from 1.4 to 84.2%. We did not find any significant relationship between PCNA index anti the histological grading, mitotic index and estrogen receptor immunoreactivity. We conclude that PCNA detected by the monoclonal antibody PC10 in formalin-fixed material looks at present unrealiable as a proliferation marker in breast carcinoma.

Sequence, evolution and ligand binding properties of mammalian Duffy antigen/receptor for chemokines

The Duffy antigen/receptor for chemokine, DARC, acts as a widely expressed promiscuous chemokine receptor and as the erythrocyte receptor for Plasmodium vivax. To gain insight into the evolution and structure/function relations of DARC, we analyzed the binding of anti-human Fy monoclonal antibodies (mAbs) and human chemokines to red blood cells (RBCs) from 11 nonhuman primates and two nonprimate mammals, and we elucidated the structures of the DARC genes from gorilla, gibbon, baboon, marmoset, tamarin, night monkey and cattle. CXCL-8 and CCL-5 chemokine binding analysis indicated that the promiscuous binding profile characteristic of DARC is conserved across species. Among three mAbs that detected the Fy6 epitope by flow cytometric analysis of human and chimpanzee RBCs, only one reacted with night monkey and squirrel monkey. Only chimpanzee RBCs bound a significant amount of the anti-Fy3 mAb. Fy3 was also poorly detected on RBCs from gorilla, baboon and rhesus monkey, but not from new world monkeys. Alignment of DARC homologous sequences allowed us to construct a phylogenetic tree in which all branchings were in accordance with current knowledge of primate phylogeny. Although DARC was expected to be under strong internal and external selection pressure, in order to maintain chemokine binding and avoid Plasmodium vivax binding, respectively, our present study did not provide arguments in favor of a selection pressure on the extracellular domains involved in ligand specificity. The amino acid variability of DARC-like polypeptides was found to be well correlated with the hydrophylicity indexes, with the highest divergence on the amino-terminal extracellular domain. Analysis of the deduced amino acid sequences highlighted the conservation of some amino acid residues, which should prove to be critical for the structural and functional properties of DARC.

Plasmodium vivax infection among Duffy antigen-negative individuals from the Brazilian Amazon region: an exception?

We present evidence for Plasmodium vivax infection among Duffy blood group-negative inhabitants of Brazil. The P. vivax identification was determined by both genotypic and non-genotypic screening tests. The Duffy blood group was genotyped by PCR/RFLP and phenotyped using a microtyping kit. We detected two homozygous FY*B-33 carriers infected by P vivax, whose circumsporozoite protein genotypes were VK210 and/or P. vivax-like. Additional efforts are necessary in order to clarify the evidence that P. vivax is being transmitted among Duffy blood group-negative patients from the Brazilian Amazon region. (C) 2007 Published by Elsevier Ltd on behalf of Royal Society of Tropical Medicine and Hygiene.

Fungicidal activity of human monocyte-derived multinucleated giant cells induced in vitro by Paracoccidioides brasiliensis antigen

Multinucleated giant cells (MGC) are characteristic cells in granulomatous disorders such as paracoccidioidomycosis (PCM) and also are formed in vitro from peripheral blood mononuclear cells by several stimuli. In this study, the authors investigated in vitro formation of MGC derived from monocytes of healthy individuals, stimulated with Paracoccidioides brasiliensis antigen (PbAg), compared with other stimuli such as IFN-gamma and supernatant of Con-A-stimulated peripheral blood mononuclear cells (CM-ConA). Besides, the fungicidal activity of monocytes and monocyte-derived MGC challenged with P. brasiliensis were compared, at a ratio of one fungus per 50 monocytes. Results demonstrated that PbAg, IFN-gamma, and CM-ConA stimuli were able to induce MGC generation, with fusion indices significantly higher than control cultures. Striking results were observed when MGC induced by PbAg and IFN-gamma presented higher fungicidal activity than monocytes, submitted to the same stimuli, showing a better capacity of these cells to kill P. brasiliensis. In summary, the results suggest that PbAg is able to induce MGC generation, and these cells presented higher fungicidal activity against P. brasiliensis than monocytes.