Optimization of antigen presentation to T cell hybridomas by purified Ia molecules in planar membranes. Ia molecule polymorphism determines the antigenic fine specificity of the response to cytochrome c peptides.

ABSTRACT

Ia molecule (Ek,b betaEk alpha or Ak betaAk alpha)-containing planar membranes were constructed with cholesterol and a 91 molar ratio of the phospholipids dipalmitoyl phosphatidylcholine and dilinoleoyl phosphatidylcholine. This lipid composition was found to be optimal for the stimulation of T cell hybridomas of different specificities. Use of this system allowed the detection of weak responses not measurable when other artificial membranes were used. Activation of the cytochrome c, Ek,b betaEk alpha-reactive hybridoma 2B4.11 using such membranes resulted in responses comparable to those found using antigen-presenting cells (APC); that is, similar amounts of IL-2 were produced at the same concentrations of antigenic peptides. Presentation of moth and pigeon cytochrome c peptides by Ek betaEk alpha- or Eb betaEk alpha-reconstituted membranes resulted in 2B4.11 response patterns similar to those previously described using B10.A or B10.A(5R) APC. These data conclusively demonstrate that differential stimulation by moth and pigeon cytochrome c peptides depends solely on structural differences in the E betaE alpha molecules used for antigen presentation.