The Env28 TCR transgenic line 6C2.16 was designed by Dr. Francis V. Chisari (The Scripps Research Institute). To generate the T cell clones, the H-2d mouse P815 mastocytoma target cell line was incubated with the major envelope polypeptide amino acids 21 to 40 from hepatitis B virus (HBV) envelope/surface antigen (HBsAg). The resulting Ld-restricted CD3+ CD4- CD8+ cytotoxic T lymphocytes (CTL) clone "6C2" was found to recognize an epitope located between residues 28-39 of HBsAg (ENV28; IPQSLDSWWTSL). The identity of the T cell receptor (TCR) Vα and Vβ chains on the surface of the "6C2" T cells was found to be Vα4.1 JαNEW and Vβ1.1 Jβ2.5. These TCR sequences were cloned into TCR cassette expression vectors (pTα and pTβ), and the resulting constructs (~15.0 kbp Tα ENV28 6C2 transgene and ~17.4 kbp Tβ ENV28 6C2 transgene) were co-microinjected into fertilized (BALB/cByJ x C57BL/6J)F2 oocytes. Founder mice were bred with BALB/cJ for germline transmission, and mice from line 16 (lineage 6C2.16) were selected. The Env28 TCR transgenic line 6C2.16 colony was backcrossed more than 12 generations with BALB/cJ inbred mice (H-2d). In 2015, albino males hemizygous for the transgene were sent to The Jackson Laboratory Repository. Upon arrival, males were used to cryopreserve sperm. To establish the living mouse colony, an aliquot of the frozen sperm is used to fertilize oocytes from BALB/cJ inbred females (Stock No. 000651).
Of note, the donating investigator reports that, at least once during backcrossing, a hemizygous female was bred to a BALB/cJ inbred male (thus the Y chromosome of the congenic strain is of BALB/cJ origin).
