Characterization of the suppressor factor produced in the spleen of dengue virus-infected mice.

The presence of a suppressor factor (SF) has been demonstrated in the homogenate of the spleen of dengue type 2 virus (DV)-infected mice which an adoptive intravenous (i. v.) transfer-suppressed DV-specific IgM-PFC in the spleen of recipient mice. The SF has been separated by prolonged agarose-gel electrophoresis from the DV-infected mice spleen homogenate. SF is highly potent, heat-labile, trypsin-resistant and unstable at acidic and alkaline pH. It is a low molecular weight substance which is dialysable and is not sedimented on ultracentrifugation.