Protein shift and antigenic variation in the S-layer of Campylobacter fetus subsp. venerealis during bovine infection accompanied by genomic rearrangement of sapA homologs

Abstract

Campylobacter fetus subsp. venerealis isolated from a case of human vaginosis was inoculated into the uterus of a C. fetus-negative heifer. Isolates obtained weekly from the vaginal mucus exhibited variations in highmolecular-mass-protein profiles from that of the original inoculum, which had a dominant 110-kDa S-layer protein. Immunoblots of the weekly isolates with monoclonal antibody probes against the 110-kDa S-layer protein and other C. fetus S-layer proteins demonstrated antigenic shifts. Genomic digests of the isolates probed with a 75-mer oligonucleotide of the conserved sapA region also indicated that antigenic variation of the S-layer is accompanied by DNA rearrangement.

Expression, secretion and antigenic variation of bacterial S‐layer proteins

“…Schematic representation of the S-protein genes (sapA) of C. fetus. The number of sapA homologues ranges from six to eight and seems to vary in time (Garcia et al, 1995). Only the position and orientation of sapA and sapA2 relative to the S-promoter are known.…”

The use of enzyme-linked immunosorbent assay and immunoblotting for the detection of Campylobacter fetus immunoglobulins in the cervico-vaginal mucus of female cattle

“…venerealis seems to be related to changes in SAP proteins, which migrate around 97 kDa, as suggested by several authors (Garcia et al 1995, GrogonoThomas et al 2000, Vargas et al 2002, Tu et al 2004, and that were strongly recognized in the immunoblotting assay performed. Therefore, these proteins may be an interesting alternative for testing, as they allow the identification of females with persistent C. fetus subsp.…”

“…In bovine isolates of Campylobacter fetus from bulls, cows and aborted fetus of brazilian herds, ten different patterns of SAP expression were demonstrated by identification of proteins with molecular mass of 97, 100, 127, and 149 kDa, obtained by an acid (glicin) method of extraction (Vargas et al 2002).Experiments using mouse and bovine models sugest that S-layer proteins is a dominant virulence factor enabling persistence in the genital tract (Garcia et al 1995) by inversion events resulting in expression of antigenically variant S-layers (Thompson 2002, Vargas et al 2002 .S-layer proteins conferes resistance to systemic defenses (Pei & Blaser 1990, Blaser & Pei 1993 preventing the binding of complement factor C3b to the C. fetus surface (Blaser 1988).…”

“…Several authors have used in the solid phase of the enzyme-linked immunosorbent assay acid extractable antigens (Blaser et al 1983, Dunn et al 1987, sonicated (Hewson 1985, Dunn et al 1987 or by distilled water extraction (Garcia et al 1995). These antigens can be classified as partially purified antigens, resulting in high sensitive and specific tests, as compared to non-purified antigens, which are less specific, or to highly purified antigens, which are less sensitive (Hirschl & Rotter 1990).…”

S-layer protein production by Corynebacterium strains is dependent on the carbon source

“…The half-life of mRNA has been found to be long : 10-15 min in Caulobacter crescentus (Fisher et al, 1988), 22 min in Aeromonas salmonicida (Chu et al, 1993), 15 min in Lactobacillus acidophilus (Boot et al, 1996a) and 14 min in Lactobacillus brevis (Kahala et al, 1997). Changes in the S-layer protein have been described in Campylobacter fetus (Garcia et al, 1995 ;Dwokin & Blaser 1996), Lactobacillus acidophilus ATCC 4356 (Boot et al, 1996b), Bacillus stearothermophilus (Sa! ra & Sleytr, 1994 ;Sa!…”