Abstract

Haemophilus influenzae type b (H.i.b) has been investigated with respect to phenotypic and genetic variations resulting in differential susceptibility to bactericidal antibody. Previous studies had shown that after growth in infected rats or in dialysate of rat serum, H.i.b strain Eag became more resistant to the bactericidal activity of antisomatic antibody. We now report that a similar phenotypic shift occurs when strain Eag is incubated with dialysate of human serum, that the increased resistance is to antibodies against determinants in the lipopolysaccharide not for the somatic antigens generally, and that most strains of H.i.b undergo the shift.

Authors

Porter Anderson, Alan Flesher, Stephen Shaw, A. Lynn Harding, David H. Smith

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