A Novel Ribonucleoprotein Complex Defined by Monoclonal Antibodies to NIH 3T3 Cells Transfected with Human Pancreatic Adenocarcinoma DNA

Three monoclonal antibodies elicited to NIH 3T3 cells transfected with DNA from a human pancreatic adenocarcinoma cell line recognized a novel ribonucleoprotein complex. Minimally, this ribonucleoprotein complex contained a Mt 240,000 protein (by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and two RNA species with apparent sizes of 1.5 and 3.0 kilobases (by formaldehyde agarose gel electrophoresis). In addition to a cytoplasmic and nuclear subcellular localization, the RNA antigen was secreted from human tumor cell lines and NIH 3T3 cells transfected with pancreatic tumor DNA (inhibitable by monen-sin) and was apparently not a viral or Mycoplasma contaminant. The ribonucleoprotein antigen was detected in some normal tissues by im-munoperoxidase but was not found in or secreted from in vitro cultured normal human fibroblasts, nontransfected or spontaneously transformed NIH 3T3 cells, or normal peripheral blood leukocytes.