An alternative pathway of T-cell activation: a functional role for the 50 kd T11 sheep erythrocyte receptor protein

Cell. 1984 Apr;36(4):897-906. doi: 10.1016/0092-8674(84)90039-4.


A series of seven monoclonal antibodies was produced against the T-lineage-specific 50 kd T11 sheep erythrocyte rosette (SRBC) receptor protein in order to define the function of the molecule. Three distinct epitopes were detected: T11(1), the SRBC binding site expressed on all T lymphocytes and thymocytes; T11(2), an epitope unrelated to the SRBC binding site but with a similar distribution; and T11(3), a neo-epitope expressed only upon T-cell activation. Simultaneous triggering of T11(2) and T11(3) epitopes by monoclonal antibodies induces T lymphocytes to proliferate and mediate their functional programs in the absence of antigen and/or antigen-presenting cells. This antigen-independent mode of triggering is distinct from that involving the T3-Ti antigen receptor complex and represents an alternate pathway of T-cell activation. Given that T11 is the earliest T-lineage surface glycoprotein to appear in thymic ontogeny and is thus expressed before T3-Ti, the former may be involved in clonal expansion and/or differentiation during early development.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, Surface / analysis
  • Cells, Cultured
  • Child
  • Child, Preschool
  • Clone Cells
  • Erythrocytes / immunology*
  • Humans
  • Infant
  • Interleukin-2 / analysis
  • Lymphocyte Activation*
  • Receptors, Antigen / immunology*
  • Receptors, Antigen / isolation & purification
  • Rosette Formation
  • Sheep
  • T-Lymphocytes / immunology*
  • T-Lymphocytes, Helper-Inducer / immunology
  • Thymus Gland / immunology


  • Antigens, Surface
  • Interleukin-2
  • Receptors, Antigen