Protective effect of implanted autologous splenic tissue in splenectomized rats exposed to i.v. Streptococcus pneumoniae.

The protective effect of splenic implantation or hemisplenectomy on the survival rate was studied in 34 Wistar rats inoculated intravenously with 8.5 x 10(6) CFU Streptococcus pneumoniae type 25, 4 months prior to the bacterial challenge, different surgical procedures were performed, dividing the animals into 5 equally large groups: (1) sham operation, (2) hemisplenectomy, (3) splenectomy with a 100% reimplantation, (4) splenectomy with a 50% reimplantation, and (5) splenectomy without reimplantation. The observation period after the bacterial inoculation was 13 d. Differences in mean survival rates were found: (1) 13 d, (2) 10.6 d, (3) 7.1 d, (4) 5.6 d, and (5) 3.1 d. The increasing survival rates correlated with increasing weights of the residual splenic tissue. This animal study indicates that residual splenic tissue may account for a lesser tendency to infection.