The Transgenic LCMV-P14 T Cell Receptor transgenic mouse was made by Dr. Hanspeter Pircher and colleagues in 1989 at the Department of Experimental Pathology in Zurich, Switzerland. The transgenic line was generated by coinjection of the P14 Tcrα and Tcrβ gene constructs into (C57BL/6 x DBA/2)F2 fertilized eggs. The male founder 327 who had 10-20 copies of both transgenes integrated onto the same chromosome was crossed to a C57BL/6 female. The line was subsequently backcrossed to C57BL/6 up to N10 and then intracrossed to establish a homozygous line. These mice were brought to Taconic in May of 1997 by Dr. B.J. Fowlkes and embryo transfer-derived into the NIAID colony. In 1998 this strain was crossed twice to homozygous Rag2 knockout mice which were backcrossed 12 generations to C57BL/10 (N12). That Rag2 strain had been developed at Taconic by Dr. Ron Schwartz of NIAID from the 129S6 founder mice created in 1992 in the laboratory of Dr. Fred Alt by Dr. Y Shinkai. The mice were again made homozygous for the transgene by intracrossing followed by selection using test crosses to outbred mice and typing for high levels of expression of the Vβ 8.1 transgene and the absence of B220+ cells in order to generate line 4113. Line 4113 was then backcrossed six additional generations to the C57BL/10-Rag2^tm1Fwa line to generate line 4356. Line 4356 was crossed to model RAGN12 to generate model 14983.