Schistosoma mansoni: identification of a 46KDa antigen of the schistosomular surface by monoclonal antibody

Um anticorpo monoclonal da subclasse IgG2a, designado C6G9, foi obtido pela imunizacao de camundongos BALB/c com antigenos de ovo de Schistosoma mansoni. Esse anticorpo monoclonal possibilitou a identificacao de um antigeno de peso molecular aproximado de 46 quilodaltons (KDa), cuja expressao foi avaliada atraves da reacao de imunofluorescencia indireta. O referido antigeno persistiu no tegumento do esquistossomulo em desenvolvimento pelo menos ate 96 horas pos-transformacao. O anticorpo monoclonal reagiu tambem com a superficie de cercarias, mas nao com a de vermes adultos. O C6G9, em presenca de complemento, foi tambem capaz de mediar niveis significativos de citoxicidade para esquistossomulos recem-transformados.

Comparison of the lowry and coomassie blue methods for the determination of protein concentration

The Lowry and Coomassie Blue methods were compared for precision when applied to Schistosoma mansoni proteins, using boving serum (BSA) as standard. The absorbance of five different concentrations was measured and the experiments were run in parallel to reduce bias in the comparison. thus, for a given technique all photometric data were obtained from reaction mixtures (BSA and test solutions) prepared and analyzed as simultaneously as possible. To interpret the results, polynomial functions of different degrees-up to the third - were calculated to fit the absorbance values to the respective protein concentrations of BSA or worm protein present in the reaction mixtures, and the standard errors of all slopes were also calculated. The protein concentration of worm extracts was calculeted by two m,ethods: 1) the ratio of the first-degree slopes of the polynomials applied to absorbance = f(x), with x being either mg BSA or ml worm extract, and 2) the utilization of the BSA function parameters to convert any worm absorbance value to protein concentration. The results obtained with the slope ratio were variable. However, the function method seemed to be reliable, especially when applied to Coomassie Blue data. When the results were derived from the BSA cubic function the concentration of soluble worm protein was calculated with a coefficient of variation of 1.20