Differences in inflammatory responses in human adult whole blood to live pneumococcal serotypes 3, 7F, 9V and 23F were investigated. Using flow cytometry and ELISA, oxidative burst, expression of activation markers CD11b/CD18, and in-vitro production of tumour necrosis factor-α, interleukin-6 (IL-6) and interleukin-8 were measured. There was no significant difference between the serotypes regarding any of the variables investigated, although there was a trend towards higher concentrations of IL-6 induced by serotypes 9V and 23F. In the present experimental model, the serotypes of Streptococcus pneumoniae shown previously to cause different degrees of inflammation were found to cause a similar inflammatory response in human whole blood.
