C1 inactivator and C3b inactivator in peripheral lymph of normal men

The concentrations of C1 inactivator and C3b inactivator were measured in the peripheral lymph of leg of normal men and compared with the concentrations in serum. Both inactivators were found in lymph, however, in concentrations lower than in serum (lymph/serum ratio for C1INA 0.236, for C3bINA 0.238). The levels of C1INA proteins in lymph were higher than of C1q and C1s (p less than 0.05), and of C3bINA higher or equal to those of C3 and C3PA. This may indicate, that the relatively high concentrations of both inactivators in the extravascular space, as compared with complement component proteins, can play a role in the control of activation process of complement in the interstitium and also explain to some extent the observed low hemolytic activity of lymph C1 and C3.