Ultrastructural localization and protective activity of a high-molecular-weight antigen isolated from Legionella pneumophila

Abstract
Immunoperoxidase labeling showed that the F-1 antigen of Legionella pneumophila is located on the bacterial cell surface. Protection against lethal intraperitoneal challenge with serogroup 1 L. pneumophila was induced in guinea pigs by heat-killed cells and F-1 antigen from serogroup 1, but not by heat-killed cells or F-1 antigens from serogroup 2, 3, or 4.