FIG. 2.

Design for the initial inoculation with SIVmac251 (10⁵ TCID₅₀ per ml) and the serial IV (A) and serial IVAG (B) passage experiments. For passage 1, plasma was collected from one IV-inoculated (22673) and one IVAG-inoculated (21743) monkey at 2 weeks p.i., then introduced IV or IVAG to one or two naive monkeys. This process was repeated for passage 2. Symbols (+) and (−) indicate whether each monkey became infected with SIV, as determined by virus isolation.