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. 2014 Mar 10;9(3):e90930. doi: 10.1371/journal.pone.0090930

Figure 4. Indirect immunofluorescence binding assay of BURK24 and BURK37.

Figure 4

Human lung adenocarcinoma A549 cells were seeded overnight onto 12×. (A) A549 cell infected with non-invasive E. coli cells followed by treatment with control serum from naive BALB/c mouse. (i) Phase contrast of A549 cells (ii) Absence of immunofluorescence indicating the failure of naive mouse serum to bind onto the non-invasive strain of E. coli. (B) A549 cells infected with Burkholderia pseudomallei NCTC 10274 followed by immunostaining using BURK24 as primary antibody and FITC conjugated anti-mouse immunoglobulin as secondary antibody. (iii) Phase contrast microscopic observation of A549 cells after immunostaining (iv) Fluorescence of the B. pseudomallei NCTC 10274 infected cell lines indicating the specific binding of BURK24 on live and intact bacteria. (C) A549 cell infected with B. pseudomallei NCTC 10274 followed by indirect immunofluorescence using BURK37. (v) A549 cells under phase contrast microscopic observation (vi) Fluorescence of the cell lines indicating the positive specific binding of BURK37 onto the bacterial cell surface as in case of BURK24. The results are representative of two independent experiments. Bar = 10 µm.