Influenza is a lipid-enveloped, pleomorphic virus. We combine electron cryotomography and analysis of images of frozen-hydrated virions to determine the structural organization of filamentous influenza A virus. Influenza A/Udorn/72 virions are capsule-shaped or filamentous particles of highly uniform diameter. We show that the matrix layer adjacent to the membrane is an ordered helix of the M1 ...

Bordetella pertussis, the causative agent of whooping cough, adheres to human monocytes/macrophages by means of a bacterial surface-associated protein, filamentous hemagglutinin (FHA) and the leukocyte integrin, complement receptor 3 (CR3, alpha M beta 2, CD11b/CD18). We show that an FHA Arg-Gly-Asp site induces enhanced B. pertussis binding to monocytes, and that this enhancement is blocked by...

Bordetella pertussis, the causative agent of whooping cough, adheres to human monocytes/macrophages by means of a bacterial surface-associated protein, filamentous hemagglutinin (FHA) and the leukocyte integrin, complement receptor 3 (CR3, ~xmfl2, CDllb/CD18). We show that an FHA Arg-Gly-Asp site induces enhanced R pertussis binding to monocytes, and that this enhancement is blocked by antibodi...

Leukocytosis-promoting factor (LPF) was purified from the supernatant of a 5-day liquid culture of Bordetella pertussis strains Tohama and no. 134. The preparations appeared to be filamentous molecules (2 by 40 nm) and contained histamine-sensitizing and hemagglutinin activities in addition to leukocytosis-promoting activity. Active protection tests in mice demonstrated strong protective activi...