Peripheral blood neutrophil function in germfree and conventional rats

The superoxide anion production and the myeloperoxidase activity between polymorphonuclear cells (PMNs) from conventional and germfree rats were compared. Furthermore, the response to recombinant human granulocyte colony stimulating factor (G-CSF) between both groups of rats was also examined. Our present investigation showed that: (1) the basal superoxide anion production by PMNs in germfree rats (2.1 +/- 0.5 nmol/min/1 x 10(6) PMNs) is less than one fourth of that of conventional rats (9.5 +/- 2.9 nmol/min/1 x 10(6) PMNs). (2) the myeloperoxidase activity of PMNs from germfree rats (38.1 +/- 5.2 nmol/min/1 x 10(6) PMNs) is 1.7 times that of conventional rats (22.4 +/- 4.9 nmol/min/1 x 10(6) PMNs). (3) G-CSF administration increased the number of PMN, 12.4 times in the germfree rats compared with 3.9 times in the conventional rats. (4) the PMNs induced by G-CSF do not differ in the superoxide anion producing activity. However the myeloperoxidase activity decreased in the G-CSF induced PMNs of both groups of rats. From our data, the conventional rats could have a more effective killing activity than the germfree rats. Furthermore, germfree rats may be used as a powerful tool for assay of other biological substances relating to immune system and its regulation.