A refined genome phage display methodology delineates the human antibody response in patients with Chagas disease.

Large-scale mapping of antigens and epitopes is pivotal for developing immunotherapies but challenging, especially for eukaryotic pathogens, owing to their large genomes. Here, we developed an integrated platform for genome phage display (gPhage) to show that unbiased libraries of the eukaryotic parasite Trypanosoma cruzi enable the identification of thousands of antigens recognized by serum samples from patients with Chagas disease. Because most of these antigens are hypothetical proteins, gPhage provides evidence of their expression during infection. We built and validated a comprehensive map of Chagas disease antibody response to show how linear and putative conformation epitopes, many rich in repetitive elements, allow the parasite to evade a buildup of neutralizing antibodies directed against protein domains that mediate infection pathogenesis. Thus, the gPhage platform is a reproducible and effective tool for rapid simultaneous identification of epitopes and antigens, not only in Chagas disease but perhaps also in globally emerging/reemerging acute pathogens.

Desempenho de testes sorológicos para sífilis, treponêmicos (ELISA) e não treponêmicos (VDRL e RPR), na triagem sorológica para doadores de sangue- confirmação dos resultados por meio de três testes treponêmicos (FTAABS, WB e TPHA) / Evaluation of serological tests for syphilis, treponemal (ELISA) and non-treponemal (VDRL and RPR), in blood donors serological screening: confirmation of results by three treponemal tests (FTAABS, WB and TPHA)

Este estudo constitui uma análise do desempenho do teste sorológico treponêmico ELISA Recombinante Wiener lab. e de seis testes não treponêmicos (Laborclin: VDRL Bras. RPR Bras e RPR TRUST: Wama: VDRL e RPR; Wiener:USR) na triagem sorológica de doadores de sangue. Os resultados repetidamente reagentes (RR) foram confirmados por meio de três testes treponêmicos: FTAabs (Wama), WB (in house) e TPHA (bioMérieux). Foram analisadas 2990 amostras de soro. O teste VDRL (USR), utilizado inicialmente na triagem sorológica, apresentou reatividade em 11 (0,4por cento) amostras, com títulos variando de 1/1 até 1/32. Nos demais testes não treponêmicos, observou-se reatividade em um número de amostras que variou de 4 a 14, num total de 20 (0,7por cento) amostras das 2990 analisadas. O teste treponêmico ELISA apresentou resultados RR em 42 (1,4por cento) das amostras analisadas, entre as quais 8 (0,3por cento) se mostraram reagentes a, pelo menos, um teste não treponêmico. Das 42 amostras RR pelo teste ELISA submetidas aos testes confirmatórios de FTA-abs, TPHA e WB, 9 (21,4por cento) foram negativas para os três testes, 8 (19,1por cento) foram positivas para WB e TPHA e negativas para o FTA-abs e 25 (59,5por cento) foram positivas para os três testes. A especificidade do teste ELISA atingiu 99,7por cento, considerando-se o WB e o TPHA como confirmatórios. As 12 amostras que apresentaram resultados não reagentes no teste ELISA, mas mostraram algum tipo de reatividade para os testes não treponêmicos, tiveram resultado negativo nos testes confirmatórios utilizados. Mesmo que o descarte de bolsas seja maior quando se utiliza teste treponêmico, essa conduta parece ser a mais segura na triagem sorológica de doadores de sangue.

High prevalence of GB virus C/hepatitis G virus RNA among Brazilian blood donors.

The aim of this study was to investigate the presence of the Hepatitis G Virus on a population of blood donors from S o Paulo, Brazil and to evaluate its association to sociodemographic variables. Two RT-PCR systems targeting the putative 5'NCR and NS3 regions were employed and the former has shown a higher sensitivity. The observed prevalence of HGV-RNA on 545 blood donors was 9.7% (CI 95% 7.4;12.5). Statistical analysis depicted an association with race/ethnicity, black and mulatto donors being more frequently infected; and also with years of education, less educated donors presenting higher prevalences. No association was observed with other sociodemographic parameters as age, gender, place of birth and of residence. DNA sequencing of nine randomly chosen isolates demonstrated the presence of genotypes 1, 2 and 3 among our population but clustering of these Brazilian isolates was not detected upon phylogenetic analysis.

High prevalence of GB Virus C/Hepatitis G Virus RNA among Brazilian blood donors

The aim of this study was to investigate the presence of the Hepatitis G Virus on a population of blood donors from São Paulo, Brazil and to evaluate its association to sociodemographic variables. Two RT-PCR systems targeting the putative 5'NCR and NS3 regions were employed and the former has shown a higher sensitivity. The observed prevalence of HGV-RNA on 545 blood donors was 9.7 percent (CI 95 percent 7.4;12.5). Statistical analysis depicted an association with race/ethnicity, black and mulatto donors being more frequently infected; and also with years of education, less educated donors presenting higher prevalences. No association was observed with other sociodemographic parameters as age, gender, place of birth and of residence. DNA sequencing of nine randomly chosen isolates demonstrated the presence of genotypes 1, 2 and 3 among our population but clustering of these Brazilian isolates was not detected upon phylogenetic analysis

Three cases of infection with hepatitis C virus genotype 5 among Brazilian hepatitis patients.

During the course of routine genotyping of hepatitis C virus isolates by 5' noncoding region sequencing, three samples were found to bear genotype 5-specific nucleotides. A serotyping method was subsequently applied and confirmed the finding. This is the first report of the occurrence of genotype 5 in Brazil.