抄録
Preformed soluble immune complexes (ICs) of various sizes were incubated with peritoneal macrophages (Mφs) and polymorphonuclear leukocytes (PMNs) from control and nephritic rats at 37°C for lhr to 24hr and the rate of ICs degradation was studied.
Immune complexes, being soluble in antigen excess of double, five and twenty times were made of either heterologous (rabbit) antibodies or homologous antibodies with 125I-labeled BSA.
In control cells, the degradation rate by either Mφs or PMNs reached the maximum when poorly soluble ICs of double antigen excess were used, and lower level at ICs of 5 times antigen excess. ICs of 20 times antigen excess were almost nondigestible and there was no difference with the control (BSA + normal rabbit sera) . Optimal cell number and antibody concentration were those of more than 5.0×106 cell/ml and the amount larger than 35.0μg/ml antibodies, respectively. As expected, addition of fresh autosera or guinea pig complement to the test tubes resulted a two-fold increase in the rate of the degradation.
When cells were tested from rats at various points in the course of glomerulonephritis, both Mφs and PMNs were shown to degradate ICs in the way as same as the control. There was no evience of less ICs digestibility among cells from rats with the severest glomerulonephritis. While, less degradation was shown with ICs made of homologous antibodies when Mφs and PMNs from the control rats were incubated with, further study is necessary.
These observations indicate that PMNs do digest large quantities of ICs through their Fc receptors just as same as Mφs in vitro. The results were the same when the source of PMNs not only from the control rats but also from rats with severe glomerulonephritis was used.
