Analysis of expression of flagella by Salmonella enterica serotype Typhimurium by monoclonal antibodies recognising both phase specific and common epitopes

Monoclonal antibodies specific for phase 1 ("i" antigen), phase 2 ("1,2" an tigen) and common epitopes of the flagellins of Salmonella enterica serotyp e Typhimurium were raised. Having confirmed their specificity, the monoclon al antibodies were used to develop semi-quantitative ELISAs in order to ass ess the relative expression of the two phases by strains of Typhimurium. Th e majority of Typhimurium strains representative of a wide cross-section of definitive types from animal and environmental sources preferentially expr essed phase 1 antigen in vitro. DT40 strains were unique in expressing phas e 2 preferentially. The ratio of phase 1 to phase 2 expressed by strains te nded to be constant for any one strain when strains were grown on a number of conventional laboratory media. However, the ratio of phases was shown to be modulated by incubation at 42 degreesC and buffering media at pH values , notably 4.5, other than neutral. Selenite broth and Rambach media repress ed flagellation. Crown Copyright (C) 2001 Published by Elsevier Science B.V . All rights reserved.