Table 2.

Immunization of Balb/c Mice with Affinity-purified Recombinant NspA Protein Confers Protection against Subsequent Challenge with N. meningitidis Strain 608B

		Number of living mice after the bacterial challenge*
Groups		24 h		72 h		% Survival
10 μg of purified  NspA protein		20/20		16/20		80
20 μg of purified  NspA protein		9/10		8/10		80
20 μg of BSA		6/10		2/10		20
20 μg of concentrated  E. coli supernatant		7/10		2/10		20
Phosphate buffered  saline		8/10		0/10		0

^*The mice were challenged with 1 ml of a suspension containing 1,000 CFU of N. meningitidis strain 608B, 4% mucin (Sigma), and 1.6% hemoglobin (Oxoid).