Fimbria-specific antibodies detach Escherichia coli from human cells

Genetic control of serum antibody responses of inbred mice to type 1 and type 2 fimbriae from Actinomyces viscosus T14V

Antibodies reactive with type 1 and type 2 fimbriae from Actinomyces viscosus T14V specifically inhibit the adherence of A. viscosus T14V to salivary pellicle-coated tooth surfaces and other bacteria, and these antibodies are thought to modulate colonization by this microorganism. These studies were done to determine whether previously noted differences in the antibody responses of inbred mice to type 1 and type 2 fimbriae might be under genetic control. The serum immunoglobulin G (IgG) and IgM antibody responses of inbred, F1 hybrid, and H-2 congenic mice, immunized with A. viscosus T14V cells, were analyzed by enzyme-linked immunosorbent assays for antibodies reactive with A. viscosus T14V whole-cell type 1 and type 2 fimbriae. The results confirmed earlier findings and indicated striking variations in the amounts of IgG anti-type 1 (23-fold) and anti-type 2 (48-fold) fimbria antibodies elicited. The responses of the 17 inbred strains tested showed a relatively continuous distribution from high to low, as well as marked differences in the responses of H-2 and Igh-C identical strain pairs. An analysis of the responses of F1 hybrid and H-2 congenic mice indicated dominance of the low-responder gene(s) and control by H-2-linked genes. Antisera from two high-responder strains inhibited in vitro bacterial adherence to a much greater degree than antisera from a low-responding strain. These data suggest polygenic control of the magnitude of the IgG anti-type 1 and anti-type 2 fimbria antibody responses by H-2-linked genes as well as background genes not associated with H-2 or Igh-C loci.

Transport of nutrients into the renal brush border membrane vesicles as marker in evaluating the role of antipili antibodies in modulation of ascending pyelonephritis in rats

The uptake of D-glucose, L-aspartate, L-lysine and L-proline was investigated in renal brush border membrane (BBM) vesicles prepared from control, infected or passively-immunized-infected rats. Except L-aspartate, a progressive decrease in the uptake of these nutrients in both infected and immunized-infected groups during the course of infection was observed, but the changes were less apparent in immunized-infected rats than in non-immunized ones. The uptake of L-aspartate was increased in vesicles from early stages of infection but decreased in those from later stages. Also in L-aspartate uptake, the changes were smaller in immunized animals. The uptake of nutrients was detectable earlier than were histopathological alterations of both kidneys. The observations demonstrated that uptake of D-glucose and amino acids in the kidneys is disturbed prior to appearance of histopathological lesions and thus can be used for early detection of the disease. The data also demonstrate that antipili antibodies afford partial protection against ascending pyelonephritis.

Examination of strains of lactobacilli for properties that may influence bacterial interference in the urinary tract

Lactobacilli strains vary in their ability to interfere with colonization of uroepithelial cells by pathogenic organisms. Bacterial size, adherence capability, competitive exclusion and inhibition of pathogenic growth were examined in selected strains of lactobacilli to assess their relative importance. We tested adherence to uroepithelial cells of 34 lactobacillus isolates originating from the urogenital tract, dairy sources and chickens, and 1 lactobacillus strain isolated from a commercially available preparation. The ability to adhere differed greatly among the 34 strains, with a range of 8 to 74 bacteria per cell, and the commercial strain attached poorly with a mean of 15 bacteria per cell. Eleven strains of lactobacilli were selected and found to differ in length and width dimensions. These strains were found to exclude competitively with varying efficiency 6 strains of uropathogens from adhering to uroepithelial cells. The effective ability of Lactobacillus casei GR-1 to exclude the uropathogens confirmed previous findings and other strains (GR-2, GR-3 and A-60) gave a similar range of exclusion. The lactobacillus isolates varied greatly in their ability to inhibit the growth of 11 uropathogens under the conditions of an agar overlay inhibition assay. A combination score was allocated to each of the 11 lactobacillus strains based on size, adherence, exclusion and inhibition. Lactobacillus casei GR-1 attained the highest score while the commercial strain attained the lowest score. The results of this study identified 4 properties that should be examined to select lactobacillus strains before embarking upon bacterial interference studies to prevent urinary tract and other infections in humans.

Modulation of Actinomyces viscosus colonization of mouse teeth in vivo by immunization with fimbrial adhesins

Experiments were performed to determine whether immunization of mice with fimbrial adhesins isolated from Actinomyces viscosus T14V could modulate infection of tooth surfaces in animals challenged with the homologous strain. Saliva and sera from animals immunized in the submandibular gland region contained elevated levels of fimbria-specific immunoglobulin A (IgA) and IgG, whereas saliva and sera from sham-immunized animals did not. There was a statistically significant inverse correlation between the presence of fimbria-specific antibodies in saliva and serum and the levels of bacterial colonization on molar tooth surfaces. These results suggest that fimbrial adhesins may effectively modulate infection of tooth surfaces by periodontopathic bacteria.

Antibodies that bind to fimbriae block adhesion of Streptococcus sanguis to saliva-coated hydroxyapatite

Antibodies raised against a fimbriated, adhesive strain of Streptococcus sanguis (FW213) were found to block the adhesion of this organism to saliva-coated hydroxyapatite. Antibodies were made specific for adhesion antigens by adsorption with isogenic, nonadhesive mutants (for rabbit polyclonal adsorbed antibody) or selection based on nonreactivity with two nonadhesive mutants (for monoclonal antibody). Rabbit antibody raised against isogenic, nonfimbriated nonadhesive mutants served as a control for antibodies present, but not related to fimbriation. Adsorbed antibody and monoclonal antibody were shown to be specific for fimbriae (antigen 1), since both antibodies could be seen by immune electron microscopy to bind 3.6-nm fimbriae, reacted only with the fimbriated parent and not the mutants in a whole bacterial cell enzyme-linked immunosorbent assay, and could immunoprecipitate fimbriae from fimbrial extracts of FW213. Antibodies isolated from preimmune and mutant sera did not react with fimbriae in any of the above assays. Only adsorbed antibody and monoclonal antibody were capable of blocking the adhesion of FW213 to saliva-coated hydroxyapatite. Adsorbed antibody, purified to immunoglobulin G (IgG), was an effective inhibitor of adhesion without causing interfering cellular aggregation. Monoclonal IgG, papain-cleaved to Fab fragments to prohibit cell-to-cell cross-linking, was also a potent inhibitor of S. sanguis FW213 adhesion. Both IgG from mutant sera and Fab fragments from normal mouse IgG could not be shown to block adhesion. These data further support the hypothesis that S. sanguis fimbriae are involved in adhesion.

Enterotoxigenic Escherichia coli infections in newborn calves: a review

Diarrhea caused by enterotoxigenic Escherichia coli is an infectious bacterial disease of calves that occurs during the first few days of life. The Escherichia coli that cause the disease possess special attributes of virulence that allow them to colonize the small intestine and produce an enterotoxin that causes hypersecretion of fluid into the intestinal lumen. These enterotoxigenic Escherichia coli are shed into the environment by infected animals in the herd and are ingested by newborn calves soon after birth. There is some natural immunity to enterotoxigenic Escherichia coli; however, it often fails to protect calves born and raised under modern husbandry conditions. Hence, methods have been developed to stimulate protective immunity by vaccination of the dam. The protective antibodies are transferred passively to calves through the colostrum.