Table 2. Retrovirus vaccine studies based on Fv1 incompatibility.

		Genotype
Year	Host strain	Fv1	Fv2	H2 a	Rfv3	Vaccine strainb	Challenge Strainb	Results	Ref.
1986	(B10.A × A.BY)F1	b/b	r/s	a/b	r/s	N-tropic FV complex	B-tropic FV complex	Protection from challenge independent of H2	[43]
	(B10.A × A/WySn)F1	b/b	r/s	a/a	r/s	N-tropic FV complex	B-tropic FV complex	Protection from challenge independent of H2	[43]
1998	(B10.A × A/WySn)F1	b/b	r/s	a/a	r/s	N-tropic F-MuLV helperc	B-tropic FV complex	Protection due to immunity, not receptor interference	[44]
1999	(B10.A × A.BY)F1	b/b	r/s	a/b	r/s	N-tropic F-MuLV helperc	B-tropic FV complex	T-cell protection transferrable to naïve host	[45], [46]
2004	B6 (adoptive transfer)	b/b	r/r	b/b	r/r	N-tropic F-MuLV helperc	B-tropic FV complex	Virus-specific antibodies are critical for protection	[47]
2013	129P2 Apobec3 KO	nr/nr	s/s	b/b	null	B-tropic FV complex	NB-tropic FV complex	Protection from challenge independent of Apobec3	This study

^a H2 dictates cell-mediated immune responses, with the b haplotype being more protective than a. ^bEntries designated as FV complex correspond to the classical FV stocks that contain F-MuLV helper virus, SFFV and LDV. ^cWithout SFFV, F-MuLV is nonpathogenic and does not cause splenomegaly.