The still elusive T cell receptor: on the possibility of a common V-gene pool for B- and T-cell-antigen receptor molecules.

The contention that VH constitutes a part of T-cell receptors for antigens was probed by purifying rabbit T cells and analysing these cells for non-immunoglobulin VH, i.e. VH not associated with L chain. A number of anti-VH antisera were employed for this purpose, the most important being goat antiserum, reacting with common a1 allotype determinants (allotype determinants expressed on free VH and H chain as well as on intact immunoglobulins), rat antibody against common non-allotype VH determinants (VH framework determinants expressed on VH and H chain as well as on intact immunoglobulins) and chicken antibody against unmasked non-allotype determinants (VH determinants accessible only in the absence of L chain). VH and L chain was quantified by radioimmunoassays on extracts and supernatants from unstimulated T cells as well as from T cells stimulated by concanavalin A and by allogeneic cells. Absolute depletion of Ig-containing and -producing cells was not achieved but in no case was an excess of VH over L chain observed. This indicated that all detected VH originated from cells of the B lineage. The cells were also cultured in the presence of labelled amino acids followed by analysis of detergent extracts and supernatants by immunoadsorption and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) fluorography. Again, no evidence for T-cell VH could be found. Affinity purified anit-VH antibody was used to label viable rabbit T cells through the use of secondary fluorescence-labelled anti-immunoglobulin antibody. No VH-specific labelling of T cells could be observed. Mixed lymphocyte cultures were carried out in the presence of affinity-purified anti-VH antibodies. No inhibition of the reaction could be discerned. The failure to detect T-cell VH is in agreement with the recent finding that the VH-genome in T cells is not rearranged in a functional manner similar to that in B cells.