Work

Pathogenesis of Campylobacter fetus infections. Failure of encapsulated Campylobacter fetus to bind C3b explains serum and phagocytosis resistance.

Year: 1988

Type: article

Abstract: Campylobacter fetus ssp.fetus strains causing systemic infec- tions in humans are highly resistant to normal and immune serum, which is due to the presence of high molecular weight (100,000, 127,000, or 149,000) surface (S-layer) proteins.Using serum-resistant parental strains (8240 LP and 23D) containing the 100,000-mol wt protein and serum-sensitive mutants (8240 HP and 23B) differing only in that they lack the 100,000-mol wt protein capsule, we examined complement binding and activation, and opsono-phagocytosis by polymor- phonuclear leukocytes.C3 consumption was similar for all four strains but C3 was not efficiently bound to 82-40 LP or 23D even in the presence of immune serum, and the small amount of C3 bound was predominently the hemolytically inactive iC3b fragment.Consumption and binding of C5 and C9 was significantly greater for the unencapsulated than the encapsulated strains.Opsonization of 8240 HP with heat-inactivated nor- mal human serum caused > 99% killing by human PMN.Simi- lar opsonization of 82-40 LP showed no kill, but use of immune serum restored killing.Findings in a PMN chemiluminescence assay showed parallel results.Association of 32P-labeled 82-40 HP with PMN in the presence of HINHS was 19-fold that for the 8240 LP, and electron microscopy illustrated that the difference was in uptake rather than in binding.These results indicate that presence of the 100,000-mol wt protein capsule on the surface of C. fetus leads to impaired C3b binding, thus explaining serum resistance and defective opsonization in NHS, mechanisms that explain the capacity of this enteric organism to cause systemic infections.previous work we have found that C. fetus isolates from humans are resistant to the bactericidal activity present in normal human or rabbit serum, that this resistance usually is high grade, and cannot be overcome by immune serum (6).Serum resistance is strongly associated with the presence of high molecular weight surface proteins on C. fetus strains (7).Recently, we identified two different laboratory-passaged

Source: Journal of Clinical Investigation

DOI: 10.1172/jci113474

Authors: M J Blaser, P F Smith, J E Repine, K A Joiner

Institutions: United States Department of Veterans Affairs, Veterans Health Administration, Denver VA Medical Center, University of Colorado Anschutz

Language: English

Topic: Salmonella and Campylobacter epidemiology

Subfield: Food Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: bronze

Funder: Johns Hopkins University