Purification of the protein X of Streptococcus agalactiae with a monoclonal antibody

Lautrou, Y.

doi:10.1016/0378-1097(91)90584-w

Cited by 3 publications

(3 citation statements)

References 12 publications

(19 reference statements)

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“…Strain variation in the opsonization requirements of type II GBS, which has been reported previously (1), appears to be the result of a complex interplay of multiple surface antigens (13). Another possible contributing factor is that this II/X strain might have expressed low amounts of surface protein X and could have been consequently less affected by antibodies resulting from immunization than was strain 443.31, which produces large amounts of this protein (9).…”

Section: Discussionmentioning

confidence: 67%

“…Seventeen strains of S. agalactiae were used in this study either to assess the specificity of the antibody response of immunized cows or to evaluate the opsonic activity of sera (Table 1). Strain 443.31 was used to produce protein X (9). Before use, strains were subcultured in Todd-Hewitt broth (THB).…”

Section: Methodsmentioning

confidence: 99%

“…In the present study, we used purified protein X (9) to investigate its immunogenicity in cows. The effect of immunization on the opsonic activity of serum was also measured in order to assess the immunological significance of protein X.…”

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confidence: 99%

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Protein X of Streptococcus agalactiae induces opsonic antibodies in cows

et al. 1991

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Protein X of Streptococcus agalactiae is a surface protein frequently associated with strains isolated from cases of mastitis of dairy cows. By immunizing cows with purified protein X, we obtained an antibody response which was restricted to X-bearing strains of S. agalactiae in a whole-cell enzyme-linked immunosorbent assay. This response resulted in an increase in the opsonic activity of serum for strains bearing protein X, as assessed through the augmentation of the chemiluminescence response of phagocytosing polymorphonuclear cells and through an increased ingestion of bacteria, although the proportion of ingested bacteria which were killed (about 60%) remained unchanged. Protein X behaved as a target of opsonins and, as such, could be a protective antigen worth incorporating in a vaccine against S. agalactiae mastitis.

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Section: Discussionmentioning

confidence: 67%

Section: Methodsmentioning

confidence: 99%

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Protein X of Streptococcus agalactiae induces opsonic antibodies in cows

et al. 1991

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The kinetics of inflammation and phagocytosis during bovine mastitis induced by Streptococcus agalactiae bearing the protein X

Rainard

Lautrou

Sarradin

et al. 1991

Veterinary Research Communications

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The protein X of Streptococcus agalactiae is a surface antigen borne by a high proportion of strains isolated from bovine mastitis. We have tested the capacity of two strains of X-bearing Streptococcus agalactiae to induce mastitis in dairy cows. The reference X-strain (411.07) produced an intramammary infection with local clinical signs in the three inoculated quarters. Another X-bearing strain (443.31) of bovine origin produced infection in all 11 quarters inoculated with only 25 or 85 colony-forming units. In naive cows, strain 433.31 induced less exudation of plasma into the milk, shedding of bacteria, macroscopic alteration, and a lower somatic cell count (SCC) than did the reference strain. Only one quarter spontaneously eliminated the infection before antibiotic treatment 9 days after inoculation. The serum of all the cows contained naturally acquired or induced antibodies to the challenge strain (443.31) and possessed opsonic activity. Before inflammation occurred, the milk was almost devoid of antibody or opsonic activities. The early phase of infection was characterized by rapid multiplication of streptococci in the milk, followed by a sharp drop in bacterial counts concomitant with the onset of inflammation. Three cows immunized with protein X displayed higher SCC and bactericidal activity in milk from the inoculated quarter at the onset of inflammation than non-immunized cows. Two of the three immunized cows underwent an early and transient febrile episode and eliminated the infection.

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Surface Proteins ofStreptococcus agalactiaeand Related Proteins in Other Bacterial Pathogens

2005

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Streptococcus agalactiae (group B Streptococcus) is the major cause of invasive bacterial disease, including meningitis, in the neonatal period. Although prophylactic measures have contributed to a substantial reduction in the number of infections, development of a vaccine remains an important goal. While much work in this field has focused on the S. agalactiae polysaccharide capsule, which is an important virulence factor that elicits protective immunity, surface proteins have received increasing attention as potential virulence factors and vaccine components. Here, we summarize current knowledge about S. agalactiae surface proteins, with emphasis on proteins that have been characterized immunochemically and/or elicit protective immunity in animal models. These surface proteins have been implicated in interactions with human epithelial cells, binding to extracellular matrix components, and/or evasion of host immunity. Of note, several S. agalactiae surface proteins are related to surface proteins identified in other bacterial pathogens, emphasizing the general interest of the S. agalactiae proteins. Because some S. agalactiae surface proteins elicit protective immunity, they hold promise as components in a vaccine based only on proteins or as carriers in polysaccharide conjugate vaccines

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Purification of the protein X of Streptococcus agalactiae with a monoclonal antibody

Cited by 3 publications

References 12 publications

Protein X of Streptococcus agalactiae induces opsonic antibodies in cows

Protein X of Streptococcus agalactiae induces opsonic antibodies in cows

The kinetics of inflammation and phagocytosis during bovine mastitis induced by Streptococcus agalactiae bearing the protein X

Surface Proteins ofStreptococcus agalactiaeand Related Proteins in Other Bacterial Pathogens

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