title: Stimulation of the in vitro immune response by factors present in the human serum.
abstract: Two distinct factors which stimulate the recovery of plaque-forming cells in the vitro immune response have been found in human serum. One acts in the presence of fetuin and the other augments the recovery of plaque-forming cells in its absence. The molecular weight of the former is higher than 1 X 10(5). The two factors could be separated from each other by ammonium sulphate fractionation. Large differences were found in the amount of these factors in sera obtained from different human donors.
mesh_terms: D000645:Ammonium Sulfate / Q000494:pharmacology; D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000276:immunology; D000509:alpha-Fetoproteins / Q000494:pharmacology
chemical_list: D000509:alpha-Fetoproteins; D000645:Ammonium Sulfate