Non‐heritable change of a spirochaete's phenotype by decoration of the cell surface with exogenous lipoproteins

Abstract

Genetic transformation of Borrelia spp. is limited in development and has found application in only one species. For a non‐genetic approach for manipulating the phenotype of these spirochaetes, we determined whether exogenous recombinant lipoproteins would incorporate in the cell's outer membrane. Using unlabelled or 125I‐labelled Osp proteins, Osp‐specific monoclonal antibodies, proteinase K and formaldehyde as reagents, we found that decoration of spirochaetes had the following characteristics. (i) Purified recombinant OspA or OspD lipoproteins associated with Borrelia burgdorferi and B. hermsii cells that lacked abundant lipoproteins of their own. (ii) This decoration of the cells with exogenous OspA did not affect cell's viability. (iii) The decoration was concentration and temperature dependent and stable for at least 24 h. (iv) Like native OspA, the recombinant OspA decorating the cells was accessible to antibodies and proteases and could be cross‐linked to the integral outer membrane protein, P66. (v) Decoration of viable B. burgdorferi and B. hermsii with OspA rendered the cells susceptible to killing by OspA‐specific antiserum. Such non‐genetic alteration of the surface of a bacterium may be used to study functions and properties of lipoproteins in situ.

Cross-Species Surface Display of Functional Spirochetal Lipoproteins by Recombinant Borrelia burgdorferi

“…This may explain the partial protection of full-length Vsps and Vlps from proteases observed in this and a previous study (54). Together with the proposed "self-decoration" of membranes with previously released lipoproteins (12), it might also account for the so far paradoxical subsurface localization of Borrelia Osp proteins (21). Yet, pending further studies on spirochetal lipoprotein export, alternatives to the Lol pathway, such as a Klebsiella oxytoca pullulanase-like type II secretion system (42) or a completely novel mechanism, cannot be excluded.…”

“…Phage display of B. burgdorferi peptides has been used to identify candidate integrin-binding proteins (18). Using a nongenetic approach, Bunikis et al described the decoration of spirochetes with exogenous lipoproteins leading to a nonheritable change in phenotype in a variety of cultivatable Borrelia species (12).…”

Probing the Borrelia burgdorferi Surface Lipoprotein Secretion Pathway Using a Conditionally Folding Protein Domain

“…We recently demonstrated that OspA and Borrelia turicatae Vsp1, a structural homolog of B. burgdorferi OspC (35,61), are anchored in the surface leaflet of the spirochetal OM (17), i.e., they ultimately adopt an "outside anchor-outside protein," or "out-out," topology. This finding corroborated prior indirect evidence obtained with recombinant lipidated OspA and OspA-mRFP1 fusion proteins (13,50,51). The transbilayer crossing of the OM by borrelial surface lipoproteins may therefore be mechanistically similar to that of other lipidated bacterial cell envelope components.…”

An ecological approach to preventing human infection: Vaccinating wild mouse reservoirs intervenes in the Lyme disease cycle

“…During the course of the study, a new Borrelia species, provisionally classified as Borrelia miyamotoi (28), was discovered in I. scapularis (30). Remaining samples from flaB PCR-positive ticks were then reanalyzed for the presence of the new species by using p66 gene primers that discriminate between B. burgdorferi and B. miyamotoi (28,31). In 4 of 81 samples from control grids and 5 of 82 samples from vaccine grids, B. miyamotoi instead of B. burgdorferi was detected.…”