EFFECTS OF TRANSFER OF HYBRIDOMAS PRODUCING VARIOUS ISOTYPES OF IMMUNOGLOBULINS ON THE C1Q METABOLISM IN MICE

In order to elucidate possible effects of immunoglobulin on C1q metabo lism at the anabolic steps, serum C1q levels and C1q mRNA of peritonea l exudate cells (PEC) and spleen cells were measured in female BALB/c mice implanted intraperitoneally with complement-(C)-fixing IgG2b- or non-C-fixing class IgG3-producing hybridomas and/or with immunoglobuli n-non-productive myeloma cells (p3x63-Ag.8.653) (myeloma 653) (2 X 10( 6)/0.2 ml) or without any treatment as controls. In the IgG2b-hybridom a-treated mice, the serum C1q levels and C1q mRNA in PEC increased con spicuously as compared with those in the controls, but C1q mRNA in spl een cells was almost equal to that in the control mice, On the other h and, in the IgG3-hybridoma-treated mice, the serum C1q levels decrease d significantly, but the extent of such decrease and the level of C1q mRNA in their PEC were almost equivalent to those in the myeloma 653-i mplanted mice, The serum C1q levels and C1q mRNA in PEC fluctuated sim ilarly in mice injected intraperitoneally with highly purified IgG2b a nd/or IgG3 preparations, These results suggest some anabolic interacti on, as well as catabolic interaction, between the C-fixing class of im munoglobulin and C1q.