TABLE 1.

The summary of the results of laboratory infection experiments

				Resistance profiles of genotypic combinations
Experiment	N	MHC	HA	BD	BK	BQ	DK	DQ	KQ
1. 1°, single LT2 (♂)	61	*	NS	—	—	—	NS	R	NS
2. 1°, single LT2 (♂ and ♀)	68	* (♀)	NS	R	—	R	—	R	—
3. 1° LT2 + 2° mix (♂ and ♀) (LT2, PMAC45/M525)	96	***	NS	NS	—	R	—	R	—
4. 1° M525 + 2° mix (♂ and ♀) (M525/PMAC51/χ4665)	98	*	NS	D	NS	NS	NS	D	NS

“MHC” denotes MHC effect on resistance and “HA” denotes heterozygote advantage (the average of all heterozygous genotypes vs. the average of all homozygous ones). Resistance profiles of genotypic combinations were tested by comparing the mean Salmonella loads of each heterozygous genotype separately against the means of the corresponding homozygotes (i.e., BD vs. BB and BD vs. DD) with independent samples t-tests. *P < 0.05; ***P < 0.001; NS, nonsignificant. Resistance: D, dominant; R, recessive; —, not tested.