Correction: An impedimetric immunosensor for diagnosis of Brazilian spotted fever in blood plasma.

Correction for 'An impedimetric immunosensor for diagnosis of Brazilian spotted fever in blood plasma' by Marx Osório Araújo Pereira et al., Anal. Methods, 2024, https://doi.org/10.1039/d3ay01308a.

An impedimetric immunosensor for diagnosis of Brazilian spotted fever in blood plasma.

Brazilian spotted fever (BSF) is a serious disease of medical importance due to its rapid evolution and high lethality. The effectiveness of the treatment mainly depends on the rapid diagnosis, which is currently performed by indirect immunofluorescence and PCR tests, which require high costs and laboratory structure. In order to propose an alternative methodology, we sought to develop an impedimetric immunosensor (IM) based on the immobilization of specific IgY antibodies for IgG anti Rickettsia rickettsii, using blood plasma from capybara (Hydrochoerus hydrochaeris), for characterization, validation and applications of the ready IM. IM selectivity was observed when comparing capybara reagent IgG (IgGcr) readings with non-reagent IgG (IgGnr). A reagent IgG calibration curve was obtained, from which the limits of detection (LOD) and quantification (LOQ) of 1.3 ng mL-1 and 4.4 ng mL-1 were calculated, respectively. The accuracy tests showed that different concentrations of IgGcr showed a maximum deviation of 20.0%, with CI between 90.00% and 95.00%. Intermediate precision tests showed a relative standard deviation of 2.09% for researcher 1 and 2.61% for researcher 2, and the F test showed no significant difference between the recovery values found between the two analysts, since Fcal 1.56 < 5.05 and P-value 0.48 > 0, 05. Therefore, an impedimetric immunosensor was developed to detect anti BSF IgG in capybara blood plasma, which greatly contributes to the improvement of diagnostic tests, cost reduction and ease of execution.

The Recombinant Protein Based on Trypanosoma cruzi P21 Interacts With CXCR4 Receptor and Abrogates the Invasive Phenotype of Human Breast Cancer Cells.

Trypanosoma cruzi P21 is a protein secreted by the parasite that plays biological roles directly involved in the progression of Chagas disease. The recombinant protein (rP21) demonstrates biological properties, such as binding to CXCR4 receptors in macrophages, chemotactic activity of immune cells, and inhibiting angiogenesis. This study aimed to verify the effects of rP21 interaction with CXCR4 from non-tumoral cells (MCF-10A) and triple-negative breast cancer cells (MDA-MB-231). Our data showed that the MDA-MB-231 cells expressed higher levels of CXCR4 than did the non-tumor cell lines. Besides, cytotoxicity assays using different concentrations of rP21 showed that the recombinant protein was non-toxic and was able to bind to the cell membranes of both cell lineages. In addition, rP21 reduced the migration and invasion of MDA-MB-231 cells by the downregulation of MMP-9 gene expression. In addition, treatment with rP21 blocked the cell cycle, arresting it in the G1 phase, mainly in MDA-MB-231 cells. Finally, rP21 prevents the chemotaxis and proliferation induced by CXCL12. Our data showed that rP21 binds to the CXCR4 receptors in both cells, downregulates CXCR4 gene expression, and decreases the receptors in the cytoplasm of MDA-MB-231 cells, suggesting CXCR4 internalization. This internalization may explain the desensitization of the receptors in these cells. Thus, rP21 prevents migration, invasion, and progression in MDA-MB-231 cells.

Egg yolk immunoglobulin Y as a promising tool to detect immune complexes in neurocysticercosis serum samples.

BACKGROUND: Neurocysticercosis (NCC) is a neglected tropical disease and its diagnosis is still a challenge due to non-specific manifestations. Neuroimaging techniques are used in the diagnosis of NCC, however, due to the high cost of these methods and the advantages presented in the use of immunological tests, such as ease of performance and satisfactory results, immunoassays are commonly used to detect antibodies against Taenia sp. antigens. The aim of the present study was to produce, characterize and apply specific polyclonal immunoglobulin Y (IgY) anti-Taenia crassiceps extracted from egg yolk of hens immunized with T. crassiceps metacestodes. METHODS: Indirect enzyme-linked immunosorbent assay (ELISA), avidity ELISA, immunoblotting and indirect immunofluorescence tests were performed for characterization of IgY antibodies. Diagnostic performance was verified by ELISA for immune complex detection testing 90 serum samples. RESULTS: Values of sensitivity, specificity, positive and negative likelihood ratios (LR+/LR-) and area under the curve (AUC) were calculated and presented the following results: sensitivity 83.3%, specificity 96.7%, AUC 0.966, LR+ 25.0 and LR- 0.17. CONCLUSIONS: Results of this pioneering and innovative study demonstrate that anti-T. crassiceps IgY antibodies present potential applicability and can be used as an efficient tool in human NCC serodiagnosis.

Serological evidence of Toxoplasma gondii infection in Melanosuchus niger (Spix, 1825) and Caimam crocodilus (Linnaeus, 1758).

Toxoplasma gondii is a protozoan with worldwide prevalence, known to affect a large variety of warm-blooded hosts. However, its ability to induce long-lasting infections in cold-blooded animals remains unclear. The most likely source of infection is through consumption of meat containing tissue cysts or by ingestion of food or water contaminated with oocysts. The current global climate change trend and the progressive degradation of natural habitats are prone to alter the distribution of ectotherm populations over a short period of time, which may favor contact between these animals and the protozoan. In association, alligator meat is considered a delicacy in many regions and its consumption has been previously related to a diversity of foodborne diseases. In that sense, we proposed in this study to search for specific antibodies against T. gondii in serum samples of two common species of alligators from the Brazilian fauna (Melanosuchus niger and Caimam crocodilus). We obtained the serum samples from 84 alligators from the Araguaia region, which were tested by agglutination assays that do not require species-specific secondary antibodies (Modified Agglutination Test - MAT; Indirect Hemagglutination Assay - IHA). From the 84 samples tested, eight (9.5%) were positive by MAT. From those, seven (87.5% of MAT+, 8.3% of the total) were also positive by IHA, reassuring a probable exposure of these animals to the parasite. Direct parasite detection in muscle fragments of one serologically reactive alligator did not yield positive results. Our results provide serological evidence that Brazilian alligators may be exposed to T. gondii and further studies should be performed to elucidate whether alligators are natural hosts of this ubiquitous protozoan parasite.

Antiparasitic effects induced by polyclonal IgY antibodies anti-phospholipase A2 from Bothrops pauloensis venom.

Activities of phospholipases (PLAs) have been linked to pathogenesis in various microorganisms, and implicated in cell invasion and so the interest in these enzymes as potential targets that could contribute to the control of parasite survival and proliferation. Chicken eggs immunized with BnSP-7, a Lys49 phospholipase A2 (PLA2) homologue from Bothrops pauloensis snake venom, represent an excellent source of polyclonal antibodies with potential inhibitory activity on parasite PLAs. Herein, we report the production, characterization and anti-parasitic effect of IgY antibodies from egg yolks of hens immunized with BnSP-7. Produced antibodies presented increasing avidity and affinity for antigenic toxin epitopes throughout immunization, attaining a plateau after 4weeks. Pooled egg yolks-purified anti-BnSP-7 IgY antibodies were able to specifically recognize different PLA2s from Bothrops pauloensis and Bothrops jararacussu venom. Antibodies also neutralized BnSP-7 cytotoxic activity in C2C12 cells. Also, the antibodies recognized targets in Leishmania (Leishmania) amazonensis and Toxoplasma gondii extracts by ELISA and immunofluorescence assays. Anti-BnSP-7 IgY antibodies were cytotoxic to T. gondii tachyzoite and L. (L.) amazonensis promastigotes, and were able to decrease proliferation of both parasites treated before infection. These data suggest that the anti-BnSP-7 IgY is an important tool for discovering new parasite targets and blocking parasitic effects.

Core biopsy no diagnóstico das lesões mamárias impalpáveis na categoria mamográfica BI-RADS® 5 / Core biopsy in nonpalpable BI-RADS® 5 breast lesions

INTRODUÇÃO E OBJETIVOS: Determinar a associação entre alterações mamográficas classificadas na categoria BI-RADS® 5 (lesões altamente suspeitas de malignidade) e diagnóstico histopatológico em material obtido por core biopsy estereotáxica e estabelecer o valor preditivo positivo dessa categoria mamográfica para o diagnóstico de câncer. MÉTODOS: Por meio de estudo retrospectivo, transversal, analítico, de comparação entre métodos diagnósticos, foram analisadas 70 core biopsies de lesões mamárias impalpáveis, classificadas como BI-RADS® 5, de 70 pacientes, atendidas em serviços privados de Anatomia Patológica e Radiologia em Recife, Brasil, entre 2001 e 2006. RESULTADOS: Foram mais acometidos: sexo feminino (97,1 por cento), mama esquerda (60 por cento) e quadrante superior externo (62,9 por cento). Os nódulos irregulares espiculados constituíram 70 por cento da amostra e as microcalcificações estavam presentes em 44,3 por cento. O número médio de fragmentos obtidos foi 6 ± 2. Os diagnósticos histopatológicos foram: carcinoma (59 casos; 84,3 por cento); lesões benignas (sete casos; 10 por cento) e hiperplasia ductal atípica ou lesão suspeita de malignidade (quatro casos; 5,7 por cento). Os nódulos irregulares espiculados corresponderam significantemente a carcinoma invasivo (p = 0,005). O carcinoma ductal in situ (CDIS) padrão comedônico puro associou-se mais frequentemente às microcalcificações na histologia. Os valores preditivos positivos foram: 84,3 por cento para a categoria mamográfica BI-RADS® 5 como um todo; 100 por cento para nódulo irregular espiculado com microcalcificações; 87,8 por cento para nódulo irregular espiculado com ou sem microcalcificações; 84,2 por cento para nódulo irregular espiculado sem microcalcificações; e 75 por cento para microcalcificações sem nódulos. CONCLUSÃO: Lesões mamárias impalpáveis da categoria mamográfica BI-RADS® 5 são de alto valor preditivo para carcinoma, particularmente os nódulos irregulares ...

INTRODUCTION AND OBJECTIVES: To determine the association between mammographic alterations classified as BI-RADS® 5 category (lesions highly suggestive of malignancy) and the corresponding histopathological diagnoses of samples obtained by stereotactic core biopsy; to establish the positive predictive value of this mammographic category for the diagnosis of cancer. METHODS: By means of retrospective cross sectional analytical study comparing diagnostic methods, we investigated seventy stereotactic core biopsies of nonpalpable breast lesions classified as BI-RADS® 5 from 70 patients seen at private Anatomic Pathology and Radiology services in Recife (Pernambuco state, Brazil) from 2001 to 2006. RESULTS: Female patients (97.1 percent) were predominantly affected. The left breast (60 percent) and upper outer quadrant (62.9 percent) were more commonly involved. Irregular spiculated nodules corresponded to 70 percent of the cases, and microcalcifications to 44.3 percent. The mean number of core fragments was 6 ± 2. The histopathological diagnoses were: carcinoma (59 cases; 84.3 percent), benign lesions (seven cases; 10 percent) and atypical ductal hyperplasia or lesion suspected of malignancy (four cases; 5.7 percent). Invasive carcinoma was significantly associated with irregular spiculated nodules (p = 0.005). Pure comedo DCIS was more frequently associated with microcalcifications on histology. The positive predictive values were: 84.3 percent for BI-RADS® 5 category as a whole, 100 percent for irregular spiculated nodules with microcalcifications, 87.8 percent for irregular spiculated nodules with or without calcifications, 84.2 percent for irregular spiculated nodules without microcalcifications and 75 percent for microcalcifications without nodes. CONCLUSION: Breast lesions classified as BI-RADS® 5 have a high positive predictive value for carcinoma, particularly irregular spiculated nodules with microcalcifications.

Specific IgA and IgG antibodies in paired serum and breast milk samples in human strongyloidiasis.

Strongyloidiasis, caused by the nematode Strongyloides stercoralis, is one of the major worldwide parasitic infections in humans. Breastfeeding may offer a potential protection against this infection. Feces, serum and milk samples were obtained from 90 lactating women from Clinical Hospital of Universidade Federal de Uberlândia, Brazil. The fecal samples were collected for parasitological diagnosis and the serum and milk samples were examined for specific S. stercoralis IgA and IgG antibodies using the indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). Fecal examination showed that the rate of prevalence of S. stercoralis infection in the lactating women was 4.4%. IFAT manifested a 16.7% positivity rate for specific IgA antibody in serum and a 28.9% rate in milk samples; specific IgG was 41.1% in serum and 25.5% in milk samples. According to ELISA the positivity rate for specific IgA antibody was 21.1% in serum and 42.2% in milk samples; specific IgG was 40% in serum and 18.9% in milk samples. In serum samples, these immunological tests showed a concurrence of 91.1% and 94.4%, respectively, in detecting specific IgA and IgG antibodies. In milk samples, they showed a concurrence of 70% and 78.9%, respectively, in detecting specific IgA and IgG antibodies. There was a statistically significant difference between concordant and discordant results of immunological tests (P<0.0001). IFAT and ELISA highly concurred in their detection of specific S. stercoralis IgA and IgG antibodies in serum and in milk samples reconfirming prior studies that the serological method is a complement to the direct diagnosis of the parasite, and suggesting that immunological methods using milk samples can also be helpful. Furthermore, in endemic areas, infants may acquire antibodies to S. stercoralis from breast milk, possibly, contributing to the enhancement of specific mucosal immunity against this parasite.