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50% neutralization titers against tier 1 virusesa
Data are from the Central Immunology Laboratory. The titers are colored according to the following color scale: yellow, 50% neutralization titers of 30 to 100; orange, 50% neutralization titers of 100 to 1,000; red, 50% neutralization titers of >1,000.
b Animal died of unrelated causes between week 12 and week 18.
