Affinity of human carcinoma cell nuclei for polyinosinic acid demonstrated by monoclonal antibodies.

The anti-nuclear cross reactivity of the monoclonal anti-actin antibodies M 372/809 was studied in some detail. The reactivity against a number of nuclear constituents was examined in the ELISA test and the capacities of these constituents to block the M 372/809 anti-nuclear and anti-actin reactions were evaluated in indirect immunofluorescence tests against tissue sections and monolayer cultures of fibroblasts and Vero cells. The repetitive polynucleotides polyinosinic and polyguanylic acid and their deoxyanalogues, actin and vimentin, were found to have the antigenic epitope.

Growth-activity related variation of a nuclear antigen in monolayer-culture cells quantitated by immunofluorometry and microspectrophotometry.

Antibodies of the hybridoma clone M 372/809 react with a nuclear antigen in growing cells. Using immunofluorometry and microspectrophotometry, the antigen was found to accumulate to a maximum coincident with the marked early increase in nuclear protein contents. The following DNA increase appeared when the intensity of the reaction with M 372/809 antibodies was decreasing.

Autoantibodies to the basal cells of squamous epithelium react with thymic epithelial cells.

Sera from carriers of hepatitis B surface antigen (17 out of 21), which reacted in immunofluorescence with the basal cell layer (BCL) of squamous epithelium, were also shown to react with a thymic stellate epithelial cell (SEC) characterized by long, dendritic-like cytoplasmic processes. Absorption of the autoantibodies against BCL of squamous epithelium (BCL-Ab) with a thymic homogenate abolished the reactivity with BCL and SEC, demonstrating that the same antigenic determinant was recognized in both cells. In the human thymus, SEC were present both in the cortex and in the medulla.

Reactivity of sera from patients with liver disease with glutaraldehyde-treated erythrocytes: role for false positive results in hemagglutination tests.

The use of glutaraldehyde as a coupling reagent in the passive hemagglutination test (HA) has gained wide application, especially for the coating of red blood cells (RBC) with glutaraldehyde-polymerized human serum albumin (pHSA), for studies of the albumin receptor on hepatitis B surface antigen (HBsAg) or for the detection of anti-albumin antibodies (AAA). Here we report a previously unrecognized reactivity with glutaraldehyde-treated RBC mainly with sera from patients with liver disease. The highest incidences of this reaction were found in patients with acute viral hepatitis A and B, namely 44 of 50 (88%) and 31 of 50 (62%) respectively.

Monoclonal antibodies to epitopes shared by actin and vimentin obtained by paramyxovirus immunization.

Three hybridoma clones producing IgM antibodies against actin were obtained from mice immunized with purified virions of paramyxoviruses. When tested on growing lung fibroblasts, ascites fluids of all clones stained in immunofluorescence cytoplasmic bundles of microfilaments, but also fibrillar networks. On colchicine-treated cells, perinuclear coils were seen in addition to microfilament bundles.