Disease relevance of vapC

• OBJECTIVE: To determine whether purified equine immunoglobulin specific for Rhodococcus equi virulence-associated proteins A and C (VapA and VapC) can confer passive protection against R. equi-induced pneumonia in foals [1].

High impact information on vapC

• Complementation analysis of the vap locus mutant showed that expression of vapA alone could restore full virulence, whereas expression of vapC, -D and -E could not [2].
• Notably, the CFS contained the previously characterized proteins VapC, VapD, and VapE, which are encoded by genes on the R. equi virulence plasmid [3].
• VapC, -D, and -E are secreted proteins coordinately regulated by temperature with VapA; the proteins are expressed when R. equi is cultured at 37 degrees C but not at 30 degrees C, a finding that is compatible with a role in virulence [4].
• The antibody response of the immunized foals confirmed that VapA and VapC are highly immunogenic [5].

Biological context of vapC

• Moreover, we identify three additional genes carried on the virulence plasmid, vapC, -D, and -E, that are tandemly arranged downstream of vapA [4].
• The antibody response to both VapA and VapC was similar in six adult horses and six naturally exposed but healthy foals, as well as in eight foals with R. equi pneumonia [6].

References