Developed is the highly sensitive and specific immuno-enzyme test-system, which is perspective for the detection of L. pneumophilia, serogroup 1. Isolated are the three hybrid cell lines that secrete monoclonal antibodies to specific epitopes of L. pneumophilia, serogroup 1 lipopolysaccharide antigen. Hyper immune rabbit sera, characterized by highly specific activity and specificity, are obtained using lipopolysaccharide antigen