Search PubMed⌕ Search

Biomedical subjects

S Avrameas

Publications and source records attributed to S Avrameas.

At least 181 records · Page 10Linked to original sources
PubMed1975

Immunocytological methods for the identification and localization of antigens.

Immunocytologic techniques allow the study of antigenic cellular constituents by optical or electron microscopy, Antibodies labelled with tracers such as fluorochromes, enzymes, radioactive isotopes, or large electron-dense molecules form the basis of these techniques. The immunochemical procedures involved in the preparation of such conjugates are well defined. Satisfactory results, however, also depend upon the proper preparation and processing of the tissue or cell suspension being studied.

Animals↗
PubMed1975

Synthesis of antibody and immunoglobulins without detectable antibody function in cells responding to horseradish peroxidase.

The kinetics of immunoglobulin-synthesizing cells (IFC) and antibody-forming cells (AFC) are compared in the popliteal nodes of mice challenged, in the hind footpads, with horseradish peroxidase (PO) in Freund's complete adjuvant. A rise in the number of IFC without antibody function precedes the appearance of AFC. IFC reach peak numbers 7 days before AFC. Control experiments show that the majority of IFC without antibody function are responding to PO and not to adjuvant. Kinetic and radioautographic data suggest that IFC arise by division and differentiation; however, the doubling time of AFC is too rapid to be accounted for by cell division alone. Double staining techniques revealed the presence of immunoglobulin and antibody in different compartments of the same cell in 5 to 15% of the AFC. It is postulated that some AFC are recruited, possibly from cells already synthesizing immunoglobulin determinants.

Animals↗
PubMed1974

Similar idiotypes in antibody-forming cells and in cells synthesizing immunoglobulins without detectable antibody function.

The occurrence of immunoglobulins with and without antibody specificity and with and without idiotypic specificity was studied, by use of enzyme-labeled antigen and antibodies, in lymph node cells of rabbits immunized with horse-radish peroxidase and hen ovalbumin. Some cells, containing immunoglobulins without detectable antibody function, were shown to contain idiotypes similar to those found in antibody-producing cells.

Alkaline Phosphatase↗
PubMed1974

Plasma membrane and internalized immunoglobulins of lymph node cells studied with conjugates of antibody or its Fab fragments with horseradish peroxidase.

Normal rat and mouse lymphoid cells were incubated at 0 degrees -4 degrees C for 1 h with purified rabbit or sheep antirat (mouse) immunoglobulin (Ig)-horseradish peroxidase (PO) conjugates or with Fab fragments of antibody coupled with peroxidase. Cells were subsequently washed and incubated in fresh medium, without labeled antibody or Fab fragments for 5-30 min at 20 degrees or 37 degrees C. With the use of the diaminobenzidine (DAB) method, distribution of peroxidase was studied in the light and electron microscopes. Fab fragments of antirat Ig antibody were iodinated with (125)I and subsequently coupled with horseradish PO. Plasma membrane and internalized immunoglobulins were detected by electron microscope autoradiography and peroxidase cytochemistry. Single- (Fab-PO), and double- ([(125)I]Fab-PO) labeled lymphoid cells showed identical patterns of surface or internal distribution of immunoglobulins. In the electron microscope, Fab-PO conjugates at 0 degrees -4 degrees C resulted in a diffuse specific staining of the plasmalemma of lymphocytes and plasma cells. Most of the small dark lymphocytes (T cells?) did not show plasma membrane Ig. Macrophages did not show plasmalemma staining, but displayed nonspecific cytoplasmic staining after incubation at 20 degrees or 37 degrees C with antibody or Fab-PO conjugates. Lymphocytes and plasma cells, after incubation with antibody-PO conjugates at 0 degrees -4 degrees C, had patchy deposits of oxidized DAB on their plasma membranes. Macrophages, similarly treated, had no plasmalemmal staining. Patch and cap formation on the plasma membrane of lymphocytes and plasma cells was seen regularly after antibody-PO incubation at 37 degrees C. Internalization patterns were different in lymphocytes and plasma cells. In lymphocytes, peroxidase staining was observed in small round or oval vesicles clustered at one pole of the cell (30 min at 37 degrees C). In plasma cells, peroxidase staining was seen in clusters of tubules resembling the Golgi apparatus. Internalization of plasma membrane IgG was less pronounced after antibody-PO labeling as compared to Fab-PO labeling.

Animals↗