Monoclonal Antibody Reactivity as a Virulence Marker for Legionella pneumophila Serogroup 1 Strains

Abstract

Using a panel of nine monoclonal antibodies, we subgrouped 85 environmental and 129 clinical Legionella pneumophila serogroup 1 isolates from Paris, France. Patients were unlikely to be epidemiologically linked either with each other or with the 44 sampled environmental sites (14 air conditioning systems and 30 buildings) that were selected at random in the Paris area. According to their monoclonal antibody patterns, isolates belonged to 14 subgroups. Monoclonal antibody 2 recognized 121 (93.8%) of 129 clinical isolates and 30 (35.3%) of 85 environmental isolates (P less than 10(-9)). Of the eight patients infected with L. pneumophila not recognized with monoclonal antibody 2, seven were immunocompromised; only 46.3% of the 121 patients infected with L. pneumophila reactive with monoclonal antibody 2 were immunocompromised (P = .02). We conclude that monoclonal antibody 2 can be used as a marker for the more virulent strains of L. pneumophila serogroup 1.

Legionella pneumophilaserogroup 1 population in Italy by monoclonal subtyping

“…This study confirms previous findings that L. pneumophila serogroup 1 isolates with the Pontiac (Oxford panel) or MAb-2 (international panel) reacting antigen marker are more virulent than the other subgroups [20][21][22] in that they are more commonly isolated from cases of Legionnaires' disease. In this study all of the strains isolated from patients were of the Pontiac subgroup, as were a high proportion of environmental isolates associated with outbreaks.…”

“…A number of monoclonal antibody subtyping schemes have been developed for epidemiological studies [6,7,11,12]. These have also been useful in identifying possible correlations between antigenic subgroups and virulence [17,[20][21][22].…”

Molecular characterization of a virulence-associated epitope on the lipopolysaccharide ofLegionella pneumophilaserogroup 1

“…A substantial antigenic diversity in serogroup 1 has been discovered using MAbs [6][7][8][9], and the standard subgrouping scheme based on the reaction patterns of seven selected MAbs has been proposed by Joly and colleagues [10]. As proven statistically in representative studies, an epitope recognized by MAb 2 of this panel is more frequently expressed on clinical than on environmental isolates and is thus associated with the virulence potential of Legionella [11][12][13]. The basis of this phenomenon is unknown.…”

Differential nitric oxide (NO) production by macrophages from mice and guinea pigs infected with virulent and avirulent Legionella pneumophila serogroup 1

“…Virulent and avirulent Leg. pneumophila are recognized differently by specific MoAbs [30]. One such antibody is directed against an antigenic determinant of Leg.…”