Defective TCR expression in transgenic mice constructed using cDNA‐based α‐ and β‐chain genes under the control of heterologous regulatory elements

We describe the generation of ovalbumin (OVA)‐specific, MHC class II‐restricted αβ T cell receptor (TCR) transgenic mice. Initial attempts at generating these transgenic mice utilized heterologous regulatory elements to drive the expression of cDNA genes encoding the separate α‐ and β‐chains of the TCR. Unexpectedly, T cells bearing the transgenic αβ TCR failed to emerge from the thymus in these mice, although the transgenes did modify endogenous TCR expression. However, subsequent modification of the approach which enabled expression of the TCR β‐chain under the control of its natural regulatory elements generated mice whose peripheral T cells expressed the transgenic TCR and were capable of antigen‐dependent proliferation. These results show that successful generation of MHC class II‐restricted, OVA‐specific αβTCR transgenic mice was dependent upon combining cDNA‐ and genomic DNA‐based constructs for expression of the respective α‐ and β‐chains of the TCR.