Demonstration and characterization of C3 receptors on rat glomerular epithelial cells.

Receptors for C3 have been demonstrated on the glomerular podocyte in humans. There is conflicting evidence regarding the presence of C3 receptors on rat glomerular cells. Even when shown to be present, the ligand specificity of the receptor has not been determined. Decapsulated rat glomeruli obtained from male Sprague-Dawley rats weighing 50 to 100 g were placed in enriched culture media. On days four to eight, cells of epithelial morphology were observed growing out of glomeruli. Receptors for C3 were detected by rosette formation of sheep erythrocytes (E) coated with antibody (A) and complement (EAC) around the glomerular epithelial cells in culture. The EACs were prepared by incubating antibody-coated sheep erythrocytes with C5-deficient mouse serum or with individual components of complement. Results indicate the presence of two types of C3 receptors on glomerular epithelial cells--CR1 for C3b and CR2 for C3d. The functional roles of these receptors remain to be elucidated.

Occurrence of infection with group B coxsackievirus in rheumatic and nonrheumatic Filipino children.

The pathogenesis of rheumatic fever has been linked to various immune mechanisms involving streptococcal antibodies and heart tissue antigens. Latent myocarditis due to group B coxsackievirus has also been considered as a possible conditioning factor. The validity of the role of infection with group B coxsackievirus in rheumatic fever was tested by determining the incidence of type-specific neutralizing antibodies in sera of Filipino children. Analysis of the results by means of a normal Z-test showed that the incidence in rheumatic children was not statistically significant in comparison to the incidence in asymptomatic children.