Non-specific immunosuppressive effects of mouse spleen extracts in vitro

Cell-free extracts were prepared from the spleens of keyhole limpet haemocyanin (KLH)-primed, ovalbumin (OVA)-primed or unprimed mice, and were shown to suppress non-specifically the secondary antibody response to TNP1000KLH in vitro. Non-specific activity was retained on storage in liquid nitrogen and was not removed by dialysis. These findings are in contrast to those reported elsewhere where it was found that cell-free extracts from the spleens of KLH-primed mice specifically suppressed the IgG response to TNP1000KLH; this discrepancy may well lie in the initial immunological status of the mice used. Nevertheless it is concluded that proper account should be taken of non-specific suppressive effects when studying the activity of cell-free extracts in vitro.