experiments in which heat-treated ( 56 degrees c for 30 min , or 50 degrees c for 20 min ) serum was used , and analysis of activation of complement by lipopolysaccharides ( lps ) from each shigella sp. , suggested that lps composition , especially the o antigen polysaccharide chains , contributes to the differences among shigella spp . in susceptibility to human serum .
C0023810
lps
C0069180
o antigen