Sera of 22 individuals were examined for immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody to autologous cultured tumor cells. Reactive native IgM was detected by immune adherence in four, and IgG by Protein A hemadsorption in five, sera. Direct and absorption testing of these reactive sera against a range of normal and neoplastic cells revealed one each with specificity for a highly r...

Mechanisms by which macrophages discriminate between "mature-self" and "senescent-self" were investigated using the human red blood cell (RBC) system as a model. Conditions simulating those encountered in situ were adhered to as closely as possible by using short term culture techniques and incubating with autologous macrophages and immunoglobulins (Ig). It was found that RBC aged in vitro were...

Clostridium botulinum serotype A produces a neurotoxin composed of a 100-kDa heavy chain and a 50-kDa light chain linked by a disulfide bond. This neurotoxin is part of a ca. 900-kDa complex, formed by noncovalent association with a single nontoxin, nonhemagglutinin subunit and a family of hemagglutinating proteins. Previous work has suggested, although never conclusively demonstrated, that neu...

It is widely accepted that the serum of healthy individuals contains natural antibodies only against those blood group A or B antigens that are not expressed on the individual’s red blood cells. The mechanisms involved in tolerance to autologous blood group antigens remain unclear. In the present study, we show that IgM and IgG antibodies reactive with autologous blood group antigens are presen...

Serial studies were performed in two patients with cyclic thrombocytopenia to investigate the pathogenesis of this disorder. Mean life span of autologous platelets when platelet levels were declining was subnormal (2.4 and 0.8 days), and megakaryocytes were abundant in the bone marrow during thrombocytopenia. Megakaryocyte colony-stimulating activity could not be detected in the serum of either...

It is widely accepted that the serum of healthy individuals contains natural antibodies only against those blood group A or B antigens that are not expressed on the individual's red blood cells. The mechanisms involved in tolerance to autologous blood group antigens remain unclear. In the present study, we show that IgM and IgG antibodies reactive with autologous blood group antigens are presen...

Transfection of tumor cells with the gene encoding the costimulatory molecule B7-1 (CD80), the ligand for CD28 and cytotoxic T lymphocye antigen-4 on T cells, has been shown to result in potent T-cell-mediated antitumor immunity. As an alternative approach, this study analyzed the costimulatory capacity of a human B7-1 immunoglobulin G (IgG) fusion protein targeted to the cell membrane of human...

We have evaluated senescence related changes in canine red blood cells (RBCs) using the biotinylation system, where RBCs are labeled in vivo with biotin at the beginning of their life span, and retrieved from circulation on immobilized avidin at the end of their life span. This approach avoids the controversial use of density gradient centrifugation to collect presumably old RBCs. Furthermore, ...

Autologous immunoglobulin was detected on the cell surface of tumor cells freshly isolated from cancerous kidneys of patients with renal cell carcinoma by flow cytometry after staining with murine anti-human IgG monoclonal antibodies. Cells isolated in parallel from macroscopically normal regions of the tumorous kidneys were not specifically stained with the anti-human IgG reagents. In further ...