NADase as a target molecule of in vivo suppression of the toxicity in the invasive M-1 group A Streptococcal isolates

Table 2 Virulence (Mortality) to mouse of GAS isolates with different NADase activity

NADase	Isolate	Mortality^a (Death/Trial)	NADase^b
Low activity	1529 KN01 MDYK MUY	29% (2/7) 33% (3/9) 67% (4/6) 17% (1/6)	3.37 ± 0.66 6.19 ± 0.52 2.95 ± 0.26 2.97 ± 0.95
High activity	GT01 FI01 CR01 IYAT	80% (12/15) 60% (6/10) 100% (12/12) 67% (4/6)	57.03 ± 3.65 59.40 ± 4.76 114.30 ± 8.67 87.25 ± 5.22
No activity^c	GT01Δnga SF370	0% (0/8) 17% (1/6)	0.49 ± 0.13 -0.44 ± 0.80

a, Mortality was determined on Day 11.
b, NADase activity (units) ± standard error are indicated. One unit of NADase activity is defined as the amount (μg) of β-NAD cleaved per hour per μl culture supernatant as described previously [15].
c, Strain SF370, which encodes an inactive form of Nga [15] was added as negative control.

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