FIG. 1.

Susceptibilities of different mouse strains to intranasal Shigella infection. Age- and sex-matched groups of 4 to 10 mice were infected with serial 10-fold dilutions of wild-type S. flexneri 2457T in saline or with saline alone as described in Materials and Methods. C57BL/6 anti-asialo-GM₁ are mice depleted of NK cells as described in the text. Reported lethal doses represent the Shigella inoculum that caused ≥90% mortality.