The eucaryotic NP-1 expression vector was transformed into the NR deficient mutant of c.

It is shown through accelerated aging tests that among all materials D1308, D1311 with null- LOX-1, LOX-2 and LOX-3 have the highest germination ratio and the lowest aging index ;

Objective:To find protective antigen(PA) defective mutants of anthrax toxin with the same function as PA but with low immunogenicity, different domains of PA were mutated.