Fifteen blood samples were collected from healthy males and females (6 males &
9 females), average age (21-34 years) in heparinized sterile tubes. The extracellular
protease was extracted from a clinical isolate of Serratia marcescens that was
isolated from a patient suffering from urinary tract infection taken from the Central
Health Laboratory. The extracted protease was purified partial by two steps,
precipitation with 30-55% saturation of ammonium sulfate following with dialysis
and ion exchange chromatography DEAE-cellulose. The protease concentration was
0.15 mg/ml. Two concentration 0.258g/ml and 0.58/ml of protease were prepared
and applied in current study. Lymphocyte transformation test using whole blood was
used in order to study the effect of protease concentrations on human lymphocyte
transformation. The results show that these were highly significant differences (P <
0.05) between control samples and lymphocytes stimulating with
Phytohemagglutinin (PHA) and between control sample and 0.58g/ml protease,;
while there was no significant differences (P < 0.05) between control sample and
0.25 8g/ml protease concentration . That is mean that the higher concentrations of
protease have the same effect of PHA on human lymphocyte transformation and it is
better in effect on human lymphocyte transformation than the lowest concentration.