Antigenically stable 35 kDa outer membrane protein ofSalmonella

Abstract

Outer membrane protein (OMP) extracts from Salmonella species representing seven serogroups were examined by SDS-PAGE followed by immunoblotting. Two major proteins with apparent molecular weight of 24 and 35 kDa were identified. The latter protein was present only in Salmonella. Immunoblotting with a monoclonal antibody (MAb) 1D6 (IgA) demonstrated the 35 kDa OMP contains an antigen common for all tested Salmonella species with the exception of atypical species such as S. arizona. The type of growth media had no effect on the antigenicity of 35 kDa protein. However, the electrophoretic appearance of the 35 kDa protein was influenced by heat-treatment. Analysis of OMP extracts by SDS-PAGE and immunoblotting without heat-treatment revealed that MAb 1D6 bound several isoforms of this protein, a major form at 28 kDa and about eight minor forms in the range between 34 and 40 kDa. None of these forms contained carbohydrate moieties that may be responsible for the polymorphic appearance of the protein. These forms were converted to a single form by heat-treatment at 100°C indicating that the 35 kDa OMP is most likely a heat-modifiable protein. Furthermore, extended heattreatment (121°C, 15 min) did not affect the antigenicity of the 35 kDa OMP. Electron microscopy studies revealed that the 35 kDa OMP is exposed on a surface of the bacterial cells, although the frequency of epitopes recognized by the Mab 1D6 was low as can be inferred from the low number of gold particles attached to the cells.

Characterization of surface proteins of Cronobacter muytjensii using monoclonal antibodies and MALDI-TOF Mass spectrometry

“…The specificity of the monoclonal antibodies was further tested using SDS-PAGE and immunoblotting. The SDS-PAGE protein profiles for the OMPs observed in this study were similar to those of OMPs described by other researchers for other members of the Enterobacteriaceae [38,39]. Overall, most of the isolates contained OMP proteins with MW ranged from 34-55 kDa (Figure 2 upper panel) with majority of the isolates exhibiting proteins in the range of 36-49 kDa with the 49 kDa protein appeared in all Cronobacter species (Figure 2 upper panel).…”

Antigenic Variations Between Different Salmonella Serotypes Isolated From Chickens

“…Nearly similar results were obtained by El-Reedy et al (2007) who identified about 12 different protein bands ranging from 22-289 KD by SDS-PAGE analysis of 12 different salmonella serotypes isolated from poultry. Also there were common protein bands at 15, 26 and 35 KD identified in all isolated Salmonella serovars which agreed with the results obtained by Ames (1973), Sarasombath et al (1988) and Joradat and Zawistowski (1998) who detected the presence of 35 KD protein band in all examined salmonellae. On the other hand, S. cerro was characterized by 3 deeply stained protein bands at 120, 60.15 and 26 KD.…”

Comparative Outer Membrane Protein Analysis of High and Low-Invasive Strains of Cronobacter malonaticus

“…SDS-PAGE revealed that the band of size ~29kDa, which was shared by the four highly invasive C. malonaticus strains, was flagellin (FliC) (Figure 4 , Table 4 ). The flagellin (FliC) is a major protein of bacterial flagella, which has been shown to have a crucial role in adhesion and invasion of pathogenic bacteria (Hofstra et al, 1980 ; Jaradat and Zawistowski, 1998 ; Haiko and Westerlund-Wikström, 2013 ). The same protein band of 29kD was previously detected and identified as flagelin in five different Cronobacter species using anti-flagella antibody coupled with mass spectrophotometry (Cruz-Córdova et al, 2012 ).…”