Cloning and expression in Escherichia coli of LKP pilus genes from a nontypeable Haemophilus influenzae strain.

Nontypeable Haemophilus influenzae HF0295, isolated by aspiration from the middle ear of a patient with otitis media, expresses long, thick, and hemagglutinating pili of a single serotype (LKP1) on its surface. An intact pilus vaccine consisting of the LKP1 serotype protected chinchillas against experimental otitis media (C. C. Brinton, Jr., M. J. Carter, D. B. Derber, S. Kar, J. A. Kramarik, A. C. C. To, S. C. M. To, and S. W. Wood, Pediatr. Infect. Dis. J. 8:554-561, 1989; R. B. Karasic, D. J. Beste, S. C. M. To, W. J. Doyle, S. W. Wood, M. J. Carter, A. C. C. To, K. Tanpowpong, C. D. Bluestone, and C. C. Brinton, Jr., Pediatr. Infect. Dis. J. 8:562-565, 1989). The genes encoding LKP1 pili were cloned from a genomic library of the clinical strain as a 12.5-kilobase insert on a plasmid vector and inserted into Escherichia coli K-12. Transposon mutagenesis and deletion constructs mapped the pilus-coding region within a 7-kilobase region of insert DNA. The recombinant bacteria were found by electron microscopy to express pili morphologically similar to LKP1 pili. Purified pilus rods from the recombinant and its parental strain were composed of a single detectable protein with an apparent molecular weight of 27,500. Antibodies raised against LKP1 pili purified from H. influenzae immunologically reacted with pili from the recombinant bacteria. Pili from both strains also adhered to human erythrocytes and buccal cells with the same specificity.

F41 antigen among porcine enterotoxigenic Escherichia coli strains lacking K88, K99, and 987P pili.

Colonial morphological variations among enterotoxigenic Escherichia coli which lack K88, K99, and 987P (3P-) were shown to be correlated with expression of several surface antigens, i.e., type 1 pili, F41 pili, and somatic and capsular antigens. Such correlations were established by electron microscopy, serology, and hemagglutination of cells derived from these specific colonial types. Identification of F41 produced by the 3P- enterotoxigenic E. coli strains was made by immunodiffusion in agarose gel, immunofluorescence microscopy, subunit molecular weight determination in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and hemagglutination of F41-piliated 3P- cells and purified F41 pili. Two of the 3P- enterotoxigenic E. coli strains were also shown to be virulent in conventional neonatal pigs and calves. Intense immunofluorescence staining by reference F41 serum of ileal villi of 3P- -infected animals indicated that F41 was expressed during the disease process.

Type 1 pili (F1) of porcine enterotoxigenic Escherichia coli: vaccine trial and tests for production in the small intestine during disease.

This study was performed to determine whether the F1 (type 1) pili of a porcine strain of enterotoxigenic Escherichia coli are protective antigens and whether they are produced in the pig small intestine during disease caused by an enterotoxigenic E. coli. Reciprocal cross-absorption experiments with antisera prepared against F1 pili purified from enterotoxigenic E. coli 431 (O101:K30,99:H-:F1) and P14 (O149:K91,88ac:8H+:F1) demonstrated that the F1 antigens of the two strains were closely related or identical. Pregnant swine vaccinated with a vaccine prepared from strain P14 (F1+) responded with a significant increase in antibody against F1 in their serum and colostrum. However, the vaccinated dams did not significantly protect their suckling pigs against fatal challenge with strain 431. There was no evidence of F1 pilus production in the strain 431-infected pigs, as determined by immunofluorescent staining of ileal sections, direct electron microscopic examination of bacteria from ilea, and titration of serum agglutinins in convalescent pigs. It was concluded that strain 431 did not produce F1 in the small intestine during disease and that F1 was not a protective antigen in this system.

Prevention of colibacillosis in neonatal swine with a 4-pilus E coli bacterin.

Of 12 pregnant swine (vaccinates) given a 4-pilus enterotoxigenic E coli (ETEC) bacterin (K88, K99, 987P, F41), all developed comparable or significantly higher serum and colostral antibody levels than those of 8 pregnant swine (controls) given a 3-pilus ETEC bacterin (K88, K99, 987P). When piglets were challenged with an ETEC strain bearing the F41 antigen, those from vaccinates had significantly lower mortality, less scours, less severe clinical signs and better weight gain than those from controls.

Enterotoxigenic Escherichia coli strains that express K88 and 987P pilus antigens.

Two enterotoxigenic Escherichia coli strains from different sources expressed K88 and 987P pilus antigens.