title: The cells of origin of lymphocyte clones grown by limiting dilution.
abstract: A high proportion of the mononuclear cells separated from peripheral blood by Ficoll-Hypaque centrifugation show extensive proliferation when cloned at limiting dilution. The nature of clone-forming cells ( CFCs ) and the cells generated during clone formation were studied by cytotoxicity with antibody and complement and by immunofluorescence. Cytotoxicity prior to cloning with OKT3 plus OKT11 eliminated 99.34% of clones, indicating that virtually all CFCs are T-lymphocytes, and cytotoxicity with OKT4 or OKT8 indicated that helper and suppressor subclasses each contribute approximately half of the CFCs . Immunofluorescence of cells proliferating in clones confirmed that all clones were T-lymphocytes and showed that 47% were OKT4 positive and 47% were OKT8 positive; 6% were negative with both OKT4 and OKT8. The results indicate that in the nearly optimal conditions for proliferation provided by limiting dilution, clones arise entirely from T-lymphocytes and clone formation is a property of a variety of lymphocyte subclasses.
mesh_terms: D000911:Antibodies, Monoclonal; D002999:Clone Cells / Q000502:physiology*; D003165:Complement System Proteins / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D005455:Fluorescent Antibody Technique; D006801:Humans; D008214:Lymphocytes / Q000166:cytology*; D008722:Methods
chemical_list: D000911:Antibodies, Monoclonal; D003165:Complement System Proteins