Precursor frequency of antigen-specific T cells: effects of sensitization in vivo and in vitro

Cell Immunol. 1983 Jul 15;79(2):334-44. doi: 10.1016/0008-8749(83)90075-8.


Limiting dilution analysis (LDA) of primary lymphocyte cultures was used to determine the frequency of keyhole limpet hemocyanin (KLH)-specific precursors in the peripheral blood of unimmunized individuals. The KLH-specific precursor frequencies ranged from 1:150,000 to 1:340,000. In contrast, frequencies of KLH-specific cells in the blood from immune donors ranged from 1:25,000 to 1:42,000. LDA of KLH-stimulated primary cultures indicated that the frequency of KLH-specific cells increased with time in culture reaching a four- to fivefold expansion relative to the frequency obtained prior to culture. The data presented suggest that the enhanced kinetics of secondary T-cell responses observed after in vitro sensitization are due to a decrease in the proportion of lymphocytes which exhibit a suppressor phenotype.

MeSH terms

  • Adult
  • Antigens / administration & dosage*
  • Antigens / immunology
  • Cells, Cultured
  • Dose-Response Relationship, Immunologic
  • Epitopes / analysis*
  • Hematopoietic Stem Cells / immunology*
  • Hemocyanins*
  • Humans
  • Immunization
  • Kinetics
  • Leukocyte Count
  • Streptodornase and Streptokinase / immunology
  • T-Lymphocytes / immunology*


  • Antigens
  • Epitopes
  • Hemocyanins
  • Streptodornase and Streptokinase
  • keyhole-limpet hemocyanin