Monoclonal antibodies (Mabs) have been useful for immunoscintigraphic applications in clinical diagnosis since they were introduced in the practice of nuclear medicine. The ior egf/r3 (Centis, Cuba) is a murine monoclonal antibody against epidermal growth factor receptor (EGF-R) and has been widely used in the radioimmunodiagnosis of tumors of epithelial origin. Labeled with 99mTc, its main application in Nuclear Medicine is the follow up, detection and evaluation of tumor recurrences. The objective of this work is to describe the preparation of a lyophilized formulation (kit) for radiolabeling the Mab ior egf/r3 with 99mTc for immunoscintigraphic applications. Radiolabeling efficiency, effects on immunoreactivity, image studies and stability of the formulation are reported. The study demonstrated that the kit formulation can be labeled with 99mTc at high yields and can be used to visualize in vivo human tumors of epithelial origin by immunoscintigraphy studies.
Anticorpos monoclonais (AcM) tem sido usado para aplicações imunocintilográficas no diagnóstico clínico desde sua introdução na prática da medicina nuclear. O ior egf/r3 (Centis, Cuba) é um anticorpo monoclonal murino contra o receptor do fator do crescimento epidérmico (EGF-R) e tem sido usado extensivamente no radioimunodiagnóstico de tumores de origem epitelial. Marcado com 99mTc sua maior aplicação em Medicina Nuclear é: acompanhamento, detecção e avaliação de recorrências tumorais. O objetivo deste trabalho é descrever a preparação da formulação liofilizada (kit) para radiomarcação do AcM ior egf/r3 com 99mTc para aplicações imunocintilográficas. A eficiência da radiomarcação, efeito sobre a imunorreatividade, estudos de imagem e estabilidade da formulação são relatados. O estudo demonstrou que a formulação do kit pode ser marcada com 99mTc com alto rendimento e pode ser usado para visualizar in vivo tumores humanos de origem epitelial por estudos imunocintilográficos

99mTc has ideal nuclear properties for organ imaging in nuclear medicine, and it is obtained from the 99Mo-99mTc generator. Four different types of generators are available: chromatographic that uses 99Mo from fission of uranium; MEK solvent extraction; Tc2O7 sublimation; gel chromatographic. This work presents the preparation of gel generators of molybdenum with cerium and characterization of the gels: mass ratio between molybdenum and cerium, structure, size of particles and elution percentage of 99mTc after irradiating the gels. Eight gels were prepared at the same temperature of 50 ºC with concentrations of NaOH of 2 and 4 mol/L, mass ratio of 0.31 and 0.38 and final pH of 3.5 and 4.5. The analysis of the results proved that these gels are not adequate for preparation of the generators of 99Mo-99mTc, since the elution percentages are low, when compared with the gel of molybdenum with zirconium.
O 99mTc é o radiofármaco mais utilizado em Medicina Nuclear. Ele é obtido do gerador de 99Mo-99mTc e existem quatro tipos diferentes de geradores: cromatográfico que utiliza 99Mo de fissão; extração por solvente com MKT; sublimação do heptaóxido de tecnécio; cromatográfico tipo gel. Este trabalho apresenta a preparação de geradores tipo gel de molibdênio com cério, a caracterização desses géis com relação à quantidade de molibdênio e de cério, sua estrutura, tamanho das partículas e porcentagem de eluição do 99mTc após o gel ser irradiado. Foram preparados oito géis na temperatura de 50ºC com concentração de NaOH de 2 e 4 mol/L, relação de massa de 0,31 e 0,38 e pH final de 3,5 e 4,5. A análise dos resultados comprovou que esses géis não são adequados para preparação dos geradores de 99Mo-99mTc, já que as porcentagens de eluição são baixas, quando comparadas com o gel de molibdênio com zircônio

52Background: Despite decades of employment of control programs, schistosomiasis 53 remains a global public health problem. To further reduce prevalence and intensity of 54 infection, or to achieve the goal of elimination in low-endemic areas, there need to be 55 better diagnostic tools to detect low intensity infections in low-endemic areas as Brazil. 56The rationale for development of new diagnostic tools is because in low-endemic 57 settings, the standard Kato-Katz diagnostic method loses its sensitivity and misses low 58 intensity infections. To develop new diagnostic tools, we employed a proteomics 59 approach search for biomarkers associated with schistosome-specific immune responses 60 to develop sensitive and specific new methods for immunodiagnosis. 61 62 Methods and findings: Immunoproteomic analysis was performed on an egg extract of 63 Schistosoma mansoni using pooled sera from infected or non-infected individuals from 64 a low-endemic area of Brazil. Cross reactivity with other helminth parasites was 65 determined using pooled sera from individuals infected with different parasitic 66helminths. Using this approach we identified 23 spots recognized by schistosome acute 67 and chronic sera samples. To identify immunoreactive spots that are likely glycan 68 epitopes, we compared immunoreactivity of spots treated by sodium metaperiodate 69 oxidation of egg extract. This treatment yielded 12/23 spots maintaining 70 immunoreactivity, suggesting they are protein epitopes. From these 12 spots, 11 spots 71 cross-reacted with sera from infection with other helminths and 10 spots cross-reacted 72 with the negative control group. Spot number 5 was exclusively immunoreactive with 73 sera from schistosome-infected groups in native and deglycosylated conditions and 74 corresponds to a Major Egg Antigen. We expressed the Major egg antigen as a 75 recombinant protein and showed by western blot a similar recognition pattern of that of 4 76 the native protein. IgG-ELISA gave a sensitivity of 87.10% and specificity of 89.09% 77 represented by area under ROC curve of 0.95. IgG-ELISA performed better than the 78 conventional K-K (2 slides) identifying 56/64 cases harboring 1-10 egg per gram of 79 feces that were undiagnosed by K-K parasitological technique.80 81 Conclusions: The serological proteome approach was able to identify a new diagnostic 82 candidate. The recombinant egg antigen provided good performance in IgG-ELISA to 83 detect individuals with extreme low-intensity infections (1 egg per gram of feces). 84 Therefore, the IgG-ELISA using this newly identified recombinant major egg antigen 85 can be a useful tool to be combined with other techniques in low-endemic areas to 86 determine the true prevalence of schistosome infection that is underestimated by Kato-87 Katz method. Further, to overcome the complexity of ELISA in the field, a second-88 generation of antibody-based rapid diagnostic tests (RDT) can be developed. 89 90 Recombinant Protein, Endemic Areas. 92 93 94 95 96 97 98 99 5 100 Author Summary 101 102 ...

Schistosomiasis mansoni is a serious problem of public health in the world and the improvement and development of new diagnostics tests is necessary to the control of disease. Our group performed a study in different areas in southeast of Brazil, with acute and chronic patients. The samples of serum and feces of patients were collected and submitted to Kato‐Katz and ELISA to diagnostic. Positive patients were treated with praziquantel and monitored after treatment. Western blotting analysis using cercariae, adult worms and eggs antigens was applied to these samples for screening of immunoreactive fractions. Some fractions were more immnunoreactive to specific phases and others decreased the intensity after treatment. Five fractions were selected to compose a diagnostic kit: two with 18 and 25 kDa to detected acute phase and one with 22 kDa to chronic phase, all of cercariae newly transformed antigens; one with 50 kDa to detected acute and chronic phase and two with 17 and 20 kDa to detected the post‐treatment phase, all of egg antigens. These fractions will be indentified and recombinant proteins produced to confection of an indirect diagnostic based in lateral flow methodology. This assay is fast, simple, requires less equipment, and is an accurate tool of screening for low resource‐regions. Grant Funding Source: Supported by Capes, CNPq, Fiocruz, PDTIS (Brazil), Fiotec, UFSJ

Control constraints of Schistosomiasis include the lack of diagnostic methods with high sensitivity. We develop a prospective study in southeast Brazil to standardize new sensitive and rapid diagnostic methods for Schistosoma mansoni infection. Currently, we are investigating 6 endemic areas (>1000 individuals with chronic infection) and 84 travelers infected in a freshwater pool (with acute infection). Sera, urine, feces and saliva samples were used for the standardization/validation of innovative methods, including acute, chronic and post‐treatment patients. Comparisons are performed with eggs in feces by 24 Kato‐Katz slides and 2 analysis of Saline Gradient and clinical symptoms. With our new point‐of‐care methods using a selected recombinant protein called CCAr e other markers, we were able to detect the disease early as 10 days post‐infection and more than 95% of positive cases from chronic and low endemicity areas were obtained. Plus, POC‐CCA® test was improved with a urine concentration step that turned its sensibility from 6% to 56%. Monoclonal antibody and recombinant protein technologies allowed a superior detection method when comparing it to the conventional methods. In conclusion, data showed 100% of sensitivity of chronic patients and 98% of acute patients.Support or Funding InformationFapemig, CNPq, FIOCRUZ, PDTIS (Brazil). Fulbright, NIH, University of Georgia (USA).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

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