Antibody response and opsonization afer pneumococcal vaccination in splenectomized children and healthy persons.

A significant rise in antibody against pneumococcal types 3, 6A and 25 after pneumococcal vaccination could be demonstrated in 26 of 30 individuals (87%) using an enzyme-linked immunosorbent assay. Similar geometric mean antibody fold increases were found in splenectomized children, non-splenectomized children and healthy adults for types 6A and 25. Splenectomized children exhibited a somewhat lower, but not statistically significant, geometric mean antibody fold increase against type 3 (p = 0.10), as compared to non-splenectomized children. For the whole group a negative correlation could be demonstrated between prevaccination antibody concentration and antibody fold increase after vaccination. After vaccination an enhanced serum opsonic activity against type 3 was found by granulocyte glucose-l-14C oxidation for the whole group of 30 patients (p less than 0.05) but nine individual patients (30%) failed to exhibit an increase. No differences between the three patient groups were demonstrable. Changes in serum opsonic activity could not be detected by a pneumococcal bactericidal assay.