Chemical composition and biological activity of lipopolysaccharides prepared from type strains of Campylobacter jejuni and Campolybacter coli

Lipopolysaccharides (LPS) were extracted from seven type strains of Campylobacter jejuni and one type strain of Campylobacter coli with 45 per cent aqueous phenol. The sugar components present in all LPS were glucose, galactose, L-glycero-D-manno-heptose, 2-keto-3-deoxy-octulosonic acid and glucosamine. All but one LPS contained galactosamine, and two strains contained in addition mannose. The fatty acids present were 3-hydroxy-tetradecanoic acid, n-hexadecanoic acid and trace amounts of n-tetradecanoic acid. The LPS preparations examined showed anti-complementary effect, and were able to gelatinize Limulus amoebocyte lysate. LPS of the C.jejuni strain tested (NCTC 11168) was found to be lethal for mice and to produce the local Shwartzman reaction in rabbits.

Structural and antigenic heterogeneity of lipopolysaccharides of Campylobacter jejuni and Campylobacter coli

The techniques of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, silver staining, and immunoblotting were used to analyze the lipopolysaccharide (LPS) structure of 20 strains of Campylobacter jejuni and 4 strains of Campylobacter coli belonging to more than 22 thermostable serotypes. The LPSs of all strains examined were shown to be of a low-molecular-weight type, and these low-molecular-weight LPSs conferred heat-stable serospecificity. High-molecular-weight banding observed with both in vivo LPS in proteinase K digests of whole cell lysates and purified LPS was shown to be due to the ready ability of Campylobacter lipopolysaccharide to form aggregates rather than to the presence of O polysaccharide chains. Purified LPSs from two strains of C. jejuni were also subjected to gross chemical analysis. The high-lipid A to low-neutral sugar ratio of both LPSs was typical of LPSs lacking O polysaccharide chains.

Campylobacter microagglutination tests of swine with proliferative enteritis

A microagglutination test was developed to determine campylobacter titers in swine with proliferative enteritis. Formalinized whole cell antigens from 24 Campylobacter isolates, including C hyointestinalis (CHI), C sputorum ss mucosalis (CSM), C jejuni/coli (CJC), C fetus ss fetus (CFF), and C fecalis (CF), were tested with 9 rabbit antisera prepared against each of 3 strains of CHI, CSM, and CJC. The CHI appeared to be antigenically homogeneous. All 6 isolates of CHI agglutinated with homologous antisera at high dilutions and did not react with CSM antisera. Five of 6 isolates of CSM agglutinated with homologous antisera, whereas 1 isolate did not. Seven strains of CJC autoagglutinated in saline solution and various antisera. One of 3 CJC antisera, however, cross-reacted with CHI and CSM antigens at high dilutions. The antigens from 5 strains of CFF and CF did not react with CHI, CSM, and CJC antisera. A survey of sera from 1,052 adult pigs from production herds indicated that the majority had high titers to CHI and CSM (mean, in log2: CHI = 5.57, CSM = 6.05). Similar titers were found in weaned pigs from 3 herds with the disease and 2 of 3 herds without the disease. Pigs with confirmed lesions of proliferative enteritis, however, had low titers (mean in log2: CHI = 2.44, CSM = 3.11). Agglutinating antibodies to CHI and CSM were transmitted from farrowing gilts to neonatal pigs via colostrum. The acquired antibodies decayed to low levels in pigs at 4 weeks of age (mean in log2: CHI = 1.09, CSM = 1.27).

Human serum antibody response to Campylobacter jejuni infection as measured in an enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay was adapted to measure immunoglobulin A (IgA), IgG, and IgM classes of human serum antibody to Campylobacter jejuni. Sera were tested from healthy controls, from ill persons at various intervals after exposure to an epidemiologically implicated vehicle for Campylobacter sp. enteritis, from persons exposed to these same vehicles who remained well, and from persons who chronically drank raw milk. The major antigens in the C. jejuni acid-washed antigen preparations from three different strains all migrated at about 30,000 and 63,000. Persons with Campylobacter enteritis developed rising serum IgA, IgG, and IgM antibodies during the second week after infection; IgG and IgM elevations persisted longer than did IgA. Exposed persons who remained well showed similar, but lower, antibody rises. Chronic raw milk drinkers had elevated IgG levels, but not IgM or IgA levels, whether or not they were acutely exposed to an implicated vehicle.

Molecular identification of surface protein antigens of Campylobacter jejuni

The technique of immunoblotting was used to identify the surface protein antigens of Campylobacter jejuni. Polyclonal antisera were raised in rabbits to formalinized cells of a typical human fecal isolate, C. jejuni VC74. Surface components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Fractions analyzed included whole cell lysates, sarcosinate-extracted outer membranes, released outer membrane blebs (fragments), isolated flagella, 0.2 M glycine-hydrochloride (pH 2.2) extract, saline extract, and material released by osmotic shocking. The ability of the antisera to recognize corresponding antigens on other strains of thermophilic campylobacters and Campylobacter fetus was also determined. The results demonstrated that heat-labile antigenic specificity was conferred on C. jejuni VC74 by an outer membrane protein with an approximate molecular weight of 92,500. Both the major outer membrane protein and the flagella were immunogenic but did not confer either strain or species serospecificity on the strains tested. Another major antigen on thermophilic campylobacter cells was a surface protein with an approximate molecular weight of 31,000. This common antigen was preferentially removed by glycine extraction but was not detectable in outer membrane prepared by sarcosinate extraction.

Swine dysentery: protection against experimental challenge following single dose parenteral immunisation with inactivated Treponema hyodysenteriae

Groups of five pigs were vaccinated at three to four weeks old with either formolised Treponema hyodysenteriae in oil adjuvant alone, formolised T hyodysenteriae in oil adjuvant plus formolised Campylobacter coli in oil adjuvant, or sterile medium in oil adjuvant (as a control). Each group was challenged four weeks after vaccination by oral dosing on two consecutive occasions with pure cultures of the homologous strain of T hyodysenteriae plus direct contact with two pigs exhibiting severe swine dysentery. The disease was observed in two of five pigs immunised with T hyodysenteriae alone, three of five pigs immunised with T hyodysenteriae plus C coli and all five controls; haemorrhagic diarrhoea was exhibited only by the control group. Each pig immunised with T hyodysenteriae (alone or with C coli) recovered spontaneously, whereas four controls died. Vaccination with T hyodysenteriae also markedly reduced the severity and duration of clinical signs and of weight loss. No differences were observed in response to challenge between pigs immunised with T hyodysenteriae alone and pigs immunised with T hyodysenteriae plus C coli.

[Serologic demonstration of antibodies against Campylobacter jejuni/coli in man]

Antibody response to Campylobacter jejuni/coli infections in man was studied by microagglutination assay against homologues organisms isolated from patients and by complement fixation test against a commercially available group-specific antigen of C. jejuni/coli. Titers of agglutinating antibodies raise within 1-2 weeks post infectionem (p.i.) to an extent of about 320 (reciprocal titer) and persist about 3-4 months. CF-antibody titers raise only to about 40 but they persist for a long time. Because of the low titers in the CF-test and because of a missing seroconversion the CF-test is not suitable for the diagnosis of an acute infection. On the other hand the persisting CF-antibodies allow the diagnosis of reactive arthritis caused by C. jejuni/coli, particularly if the causative bacteria could not be cultivated.

Diffusion-in-gel enzyme-linked immunosorbent assay for routine detection of IgG and IgM antibodies to Campylobacter jejuni

A diagnostic serologic test for antibodies to Campylobacter jejuni is presented. A diffusion-in-gel enzyme-linked immunosorbent assay with a surface antigen pool from two C jejuni strains was used. In testing serum samples for antibodies to C jejuni this system possessed high specificity, reliability, sensitivity, and capacity. It is easy to perform and there is no demand for expensive equipment. IgG and IgM antibodies can be quantitated separately, which allows for discrimination between individuals with acute infections and those with antibodies remaining after recovery. One serum sample is often sufficient to obtain such information. Seven groups of individuals were investigated. Serum samples from a total of 159 patients in three different groups and from 306 healthy individuals in four different groups were tested.

Occurrence of plasmid DNA in serologically defined strains of Campylobacter jejuni and Campylobacter coli

Forty Campylobacter jejuni and 17 Campylobacter coli strains that constitute the set of reference strains for our serotyping scheme were each examined for the presence of plasmid DNA. Agarose gel electrophoresis of alkaline-extracted DNA showed the occurrence of 29 bands in 11 C. jejuni strains and 40 bands in C. coli strains. Plasmids ranged in size from 1.6 to 70 megadaltons. Most strains that carried plasmids had between 2 and 6 of them; however, one strain had 14 plasmids, and two strains contained only 1 plasmid each. Repeated electrophoresis demonstrated that all plasmid profiles were stable. A different plasmid profile was seen for each of the 19 plasmid-carrying strains, but it was clear that plasmids of the same or similar molecular weight could be found in different strains. On the basis of these findings, we are persuaded that plasmid profiles determined by a rapid procedure for DNA extraction will play a significant role in resolving complexities among strains that are difficult to serotype and could be useful in epidemiological studies in which the implicated isolates are plasmid bearers.

An acid extract as a common antigen in Campylobacter coli and Campylobacter jejuni strains

An acid extract prepared from a single strain of Campylobacter jejuni reacted with rabbit antisera against 21 strains of C. jejuni and Campylobacter coli. The immunogen is resistant to Formalin and to exposure to 100 degrees C for 30 min. The antigenic extract may have practical applications in human serology.

Enzyme-linked immunosorbent assay (ELISA) for antibodies against Campylobacter jejuni, and its clinical application

Antibody response to Campylobacter jejuni/coli (CJC) was investigated, using an enzyme-linked immunosorbent assay, ELISA. With a mixture of lipopolysaccharide from two CJC strains as antigen in ELISA, all 24 tested rabbit anti-CJC sera showed high antibody levels. However, only 70% of sera from patients with Campylobacter enteritis demonstrated an antibody response against the combined LPS antigen, using paired sera. In addition, the results obtained suggested non-specific binding of human immunoglobulin. When 24 formalinized whole CJC bacteria were used as antigen in ELISA, all corresponding rabbit antisera reacted with one strain (M 14). Essentially no unspecific binding of human immunoglobulin was obtained. Antibodies were detected in sera from healthy blood donors and at a lower level in sera from children, suggesting early immunization. In 67 enteritis patients with positive stool cultures for CJC, a significantly increased level of IgG antibodies could be detected in single or paired serum samples from 82% of the patients. An IgG titre increase occurred early in the course of infection, suggesting a boosting of an earlier immunization. IgM antibodies could be detected in the same sera in 77% of the patients. Considering both IgG and IgM analyses of the enteritis sera, 94% of the patients were positive in Campylobacter ELISA serology compared with only 5% of healthy controls.

Regulatory effect of monocytes on T cell proliferative responses to oral microbial antigens

Mononuclear cell preparations isolated by Ficoll-Hypaque centrifugation from human peripheral blood were found to vary considerably in the number of monocytes they contained (mean, 20.3%; range, 13 to 33%). The regulatory role of monocytes in T cell proliferative responses to sonic extracts of a panel of oral microorganisms was therefore investigated. T cells were fractionated by anti-immunoglobulin chromatography and depleted of monocytes by treatment with a monoclonal anti-human Ia-like (DR locus antigen) antibody and complement. Purified populations of monocytes were obtained by extensive adherence procedures. The resultant cell populations were greater than 95% pure, as judged by indirect immunofluorescence on a fluorescence-activated cell sorter. Monocyte-depleted T cells failed to respond by proliferation to the nonoral antigen tetanus toxoid, as well as to any oral microorganism, but retained responsiveness to phytohemagglutinin. Readdition of monocytes in final concentrations of from 5 to 15% resulted in the restoration of maximal T cell proliferation. Monocytes in greater numbers suppressed T cell responses to all sonic extracts tested.

Presence of serum agglutinins to Campylobacter sputorum subspecies mucosalis in pigs

Pigs affected with intestinal adenomatosis had agglutinating antibodies to Campylobacter sputorum subspecies mucosalis. The titres obtained varied, depending on the strain used as antigen and appeared to rise with the age of the affected animal. Examination of sera from experimental animals showed that pigs between 30 and 77 days old rarely had antibody, even when they had been exposed to infection. Evidence is also presented indicating that the serological response is specific and that in a limited examination of sera derived from pigs at slaughter almost all animals had high levels of antibody.

Seroepidemiological studies with Campylobacter fetus

324 sera from unselected male and 581 sera from female patients as well as 268 sera from prostitutes were studied for antibodies against Campylobacter fetus using the complement fixation test. Antigen was Campylobacter fetus subspecies intestinalis. 3.9% of the sera showed low but relevant antibody titers. Statistically significant differences don't exist between the three population investigated. Serological cross reactions could not be observed using Salmonella typhimurium, Shigella flexneri, Escherichia coli O119 and Klebsiella pneumoniae. Antigenic relationship however was observed with the subspecies jejuni and fetus.

Clinical and serological studies in patients with Campylobacter fetus ssp. jejuni infection: II. Serological findings

The serological responses of 53 patients with Campylobacter fetus ssp. jejuni enteritis were determined with formalinized, boiled and autoclaved antigen suspensions of four reference strains and the autologous isolate. Agglutinin titres of 400 or greater were found against both formalinized and boiled reference antigens in 64% of the patients. Using boiled reference antigens five seropositive patients were found who had not been detected with the formalinized reference antigens, and vice versa. Autoclaved antigens were less useful. The use of paired sera permitted the demonstration of a serological response in some additional patients, although their maximal titre did not exceed 200. The total number of patients with serological responses to reference antigens was thus 48 (91%). The use of autologous antigens detected only one further patient.

Serological response to Campylobacter jejuni/coli infection

The antibody response to Campylobacter jejuni/coli infection was investigated in 59 patients involved in two outbreaks of milk-borne infection and in sporadic infections in the community. Agglutinins and complement-fixing (CF) antibodies were detected in nearly all these patients. Agglutinins were present in 25% of normal sera at low titres (not greater than 1/160) but CF antibody titres of 1/4 or 1/8 were present in only 2.0%. The agglutination reactions in convalescent sera were best developed with the homologous or an antigenically similar strain whereas the CF test, with sonicated organisms as antigen, was less strain-specific and was more suitable as a routine test. Antibody was present seven to 10 days after the onset of symptoms.

Serology of Campylobacter fetus ss. jejuni )"related" campylobacters). Demonstration of strain-specific and interstrain-related antigens by immunoelectrophoresis and co-agglutination

Rabbit antisera against two strains of Campylobacter fetus ss. fetus (serotype A), two strains of C. fetus ss. intestinalis (serotypes A and B respectively), and eight stains of C. fetus ss. jejuni were used in serological studies of these strains with the use of co-agglutination (COA), line-rocket immunoelectrophoresis (L-RIE) and rocket-line immunoelectrophoresis (R-LIE). Whole bacterial cells, either heated at 56 degrees C. boiled or atuoclaved, were used in COA tests. Unheated sonicates were used in L-RIE, and sonicates, unheated, boiled or autoclaved, in R-LIE. The antigenic properties of C. fetus ss. fetus and C. fetus ss. intestinalis were distinctly different from those of the thermophilic C. fetus ss. jejuni strains as shown both by COA and L-RIE. Serotypes A and B of the two former species were also differentiated. In COA tests the C. fetus ss. jejui=ni organisms gave the strongest reactions with homologous antibodies, but several interstrain cross-reactions were seen. By absorption strain specific COA reagents were obtained. Several reactions of identity indicating cross-reactive antigens were also seen with L-RIE within the ss. jejuni group. These results generally agreed with those obtained by COA. With the use of unheated, boiled or autoclaved organisms or sonicates heat labile antigens were differentiated from heat stable ones with the use of COA and R-LIE. The apparent antigenic heterogeneity of Campylobacteria indicates the importance of their serological grouping, e.g. for clinical and epidemiological investigations. COA and immunoelectrophoresis techniques can be effectively applied for such studies.

Lymphoproliferative responses to oral bacteria in humans with varying severities of periodontal disease

We assessed in vitro the lymphocyte blastogenic resp onsess of peripheral blood lymphocytes to antigen extracts of a large battery of oral microorganisms in a population of humans with varying severities of periodontal disease. When the magnitudes and frequencies of statistically positive blastogenic responses to various oral microorganisms were compared, three general patterns emerged. The Actinomyces species proved to be potent stimulators of lymphocyte blastogenesis in most subjects tested, whereas Streptococcus sanguis, Campylobacter, and Eikenella corrodens stimulated few individuals. The response to these organisms correlated poorly with the severity of periodontal disease in the tested patients. However, several gram-negative anaerobic organisms, including Bacteroides asaccharolyticus and Treponema denticola, elicited statistically more frequent positive response in subjects with destructive periodontitis compared with patients with gingivitis. These results, taken together with recent microbiological findings, suggest that the specificity of the lymphocyte blastogenic response to antigens of oral bacteria correlates with the presence of these organisms in the subgingival microflora during various periodontal disease states.

Antigens of Campylobacter fetus subsp fetus eliciting vaccinal immunity in heifers

These studies were designed to identify the antigens of Campylobacter fetus subsp fetus that elicit vaccinal immunity. Heifers were vaccinated subcutaneously twice (42 days between vaccinations) with bacterins containing K, O, and H antigens (group A), O and H antigens (group B), or O antigen (group C) of the challenge strain. Five heifers were not vaccinated and served as controls (group D). Two weeks after heifers were given the second vaccination, the immunity of all heifers was challenge exposed by inoculating a live culture against the cervical os. Cervicovaginal mucus samples were examined by microbiological culture technique, using a selective medium, at 7- and 14-day intervals after challenge exposure. One of the six vaccinated heifers in group A became infected, as did all vaccinated heifers in groups B and C and the controls (group D). Only heifers vaccinated with bacterin containing K antigen were resistant to experimental infection with C fetus subsp fetus (P = 0.0002). Humoral antibody responses to whole-cell antigen were monitored, using a tube agglutination test, with and without treatment of the serum with 2-mercaptoethanol. An anamnestic antibody response of 2-mercaptoethanol-resistant antibody was detected in heifers in both groups A and B. An agglutination test (IGGK) was developed to measure immunoglobulin G directed against the K antigen and was used in an attempt to correlate agglutination titers with the immunity to challenge exposure. With the IGGK test, the serum agglutination titers of heifers in group A were significantly higher (P less than 0.0001) than those of heifers in group B. The results of these studies indicate that K antigen of C fetus subsp fetus elicits vaccinal immunity and that a direct correlation exists between the IGGK test and immunity on a group basis.

Proliferative haemorrhagic enteropathy

This study indicates that viable Campylobacter sputorum subsp mucosalis are not present or are present in small numbers in the mucosa of pigs dying of proliferative haemorrhagic enteropathy. The changes present in the mucosa are similar to those seen in pigs recovering from adenomatosis and the evidence obtained indicates that the intracellular organisms observed in this condition are indeed mucosalis. The presence of large amounts of IgA in the altered tissue of both proliferative haemorrhagic enteropathy and porcine intestinal adenomatosis indicates that the failure to recover bacteria may be immunologically mediated but is not simply related to the presence or absence of antibody in the respective conditions.

Comparative efficacy of ten commercial Campylobacter fetus vaccines in the pregnant guinea pig: challenge with Campylobacter fetus serotype A

Efficacy of ten commercial Campylobacter fetus vaccines was tested in pregnant guinea pigs and compared with that of an experimental vaccine prepared from the challenge-exposure strain. If the first lot of vaccine failed to protect 50% of the guinea pigs, one or two additional lots of that vaccine were purchased and retested. Three vaccines for cattle, evaluated, as the most effective of those tested, protected 62%, 72%, and 89% of the guinea pigs from abortion; the experimental vaccine protected 98%. The two vaccines for sheep protected 50% and 61% of the guinea pigs from abortion. With the other five vaccines produced for immunizing cattle, protection was from 0% to 36%, with the exception of one lot of a vaccine that protected 74%. Blood infection was found at necropsy in only 6% of the guinea pigs given vaccines that protected 50% or more from abortion, but was found in 66% of those given vaccines that protected less than 50%. Similarly, tissue infection was found at necropsy in only 18% of the guinea pigs given vaccines that protected more than 50%, but was found in 91% of those given vaccines that protected less than 50% from abortion. Oil-emulsion adjuvants appeared to enhance protection from abortion and infection. Nodules persisted at the injection site in most of the guinea pigs immunized with vaccines containing oil-emulsion adjuvants, but rarely persisted in guinea pigs given aqueous-phase adjuvant vaccines. Comparison of efficacy of the vaccines in guinea pigs with efficacy in sheep and cattle remains to be made.

Microcapsule of Campylobacter fetus: chemical and physical characterization

The antiphagocytic antigen (antigen [a]) comprising the microcapsule of a strain of Campylobacter fetus subsp. intestinalis has been purified from culture supernatants by ammonium sulfate fractionation and free-flow electrophoresis. Antigen [a] is a glycoprotein containing about 4% carbohydrate consisting of hexose, pentose, and methylpentose. The composition of the protein was typical of bacterial extramural structural proteins in its low content of basic, aromatic, and sulfur-containing amino acids. The protein had a high content of aspartic acid, threonine, glycine, and alanine. Antigen [a] had an Rf of 0.33 on polyacrylamide gel electrophoresis and a molecular weight calculated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 98,000. In contrast to its free form in culture supernatants, antigen [a] in vesicles derived from sheared cells appeared to exist in a complex with lipopolysaccharide. This complex could be dissociated by ethylenediaminetetraacetic acid or by ethylenediaminetetraacetic acid plus Triton X-100. A mutant strain that lacked a microcapsule, when incubated with soluble antigen [a] in a calcium medium, became agglutinable by monospecific [a] antiserum and showed an additional structural layer similar in appearance to the microcapsule on its cell wall. Points of similarity are emphasized between antigen [a] of C. fetus and the outer structural protein of the taxonomically related Spirillum serpens.

The surface antigens of Campylobacter sputorum subspecies mucosalis

Campylobacter sputorum subsp mucosalis is the vibrio associated with a group of porcine enteropathies in which it is believed the primary lesion is that of adenomatosis. The surface antigens of mucosalis were investigated and individual factor sera were produced; these were used to examine a range of field strains from adenomatosis, necrotic enteritis, regional ileitis and proliferative haemorrhagic enteropathy. Neither these not sequential isolants from the same farm showed any distinctive antigenic pattern and it is suggested that changes in the surface antigens take place during the intracellular existence of the organism.

A dual vaccine for the immunisation of cattle against vibriosis

Single subcutaneous injections of a mineral oil adjuvant vaccine containing 20 mg dry weight of Campylobacter fetus subsp fetus biotype venerealis cells and 20 mg dry weight of C. fetus subsp fetus biotype intermedius cells per 5 mil dose protected 2- and 3-year-old heifers and 3- and 4-year-old cows against genital infection with either organism.

Bovine vibriosis vaccination: immunity conferred by a single biotype

An adjuvant vaccine was prepared from an Australian isolate of Campy-lobacter fetus subsp fetus biotype intermedius and injected into 23 virgin Guernsey heifers. Ten nonvaccinated animals served as controls. When challenged by the intravaginal route with a culture of either the homologous strain or biotype venerealis, weekly swabs from the anterior vagina continued to yield either biotype in 8 of 10 nonvaccinates at 6 weeks as compared with 3 of 23 vaccinates. Serology in vaccinated heifers and rabbits showed that the vaccine produced high titres of antibody against both homologous and heterologous strains.

Porcine intestinal adenomatosis associated with serologically distinct Campylobacter sputorum subspecies mucosalis

A variant of Campylobacter sputorum subspecies mucosalis which is serologically distinct from all strains previously examined is described. It has been isolated from cases of porcine intestinal adenomatosis and necrotic enteritis and in all other characteristics conforms to the description of mucosalis.

Studies on Campylobacter sputorum subspecies Mucosalis

Catalase-negative vibrios can be isolated in large numbers from the affected intestinal mucosa of pigs suffering from a range of porcine enteropathies in which the mucosa has an adenomatous component. These vibrios cannot be distinguished from strains of Campylobacter sputorum subsp. mucosalis. The resemblance between these bacteria strengthens the case already made on morphological evidence that these enteropathies have a common origin. Catalase-negative vibrios have also been isolated from the mouth and faeces of pigs. Some of these conform to the criteria established for the mucosalis subspecies but others can be differentiated from it. An antigenic analysis shows that strains of the mucosalis subspecies are closely related antigenically, but that differences may allow separation of strains.

[Biochemical and serological investigations of flagellae of Campylobacter fetus (author's transl)]

Flagellae of Campylobacter fetus group O, types 1, 2 and 7 were prepared. First they were separated from cell bodies using an ultramix. The suspension was then centrifuged for 20 mins. at 10000 rpm and the supernatant frozen at -40 degrees C. This is a simple method for the enrichment of preparations of flagellae, as they become tangled up and accumulate in the inferior third part of the frozen liquid. The physicochemical basis of this phenomenon was discussed. After thawing and spinning for 20 mins. at 5000 rpm, the sediment was suspended in 0.9% of NaC1. The purity of the preparation was checked by electron microscopy. Antibodies to this antigen showed no cross-reaction with O-Antigen, when tested by tube agglutination. The amino acid composition of flagellae from different O-antigen serotypes was different (see Tab. 1). Cysteine could not be detected and proline only in traces. After breakdown with urea followed by gel filtration on Sephadex G 200, breakdown products of diminishing molecular size were obtained (see Fig. 2). Discelectrophoresis after ultrasonic gave 8 zones (see Fig. 3). Irrespective of serotype, thin-layer chromatography of trypsin-hydrolysed flagellae always showed 9 ninhydrin-positive spots (see Fig. 1). Only breakdown products of ultrasonic reacted with antibody. After absorption of flagellar antibody with heterologous antigen, agglutination only occurred with homologous antigen (tab. 2-5). This showed that there were different flagellar antigens. Further experiments using immunoprecipitation demonstrated two common antigenic components, a and c, and a partially common antigenic factor bb (Fig. 4), and was the basis for a classification by three groups. The three antigenic components could be separated by gel electrophoresis and detected by immunoprecipitation (Figs. 5,6).

Ovine campylobacterosis: preliminary studies of the efficacy of the in vitro serum bactericidal test as an assay for the potency of Campylobacter (Vibrio) fetus subsp intestinalis bacterins

An in vitro serum bactericidal test was developed to assess the efficacy of Campylobacter fetus bacterins. Four experimental monovalent bacterins (either serotype C or A-2) and 2 commercial bivalent bacterins (a "suspect" and an "efficacious" bacterin) with aluminum hydroxide adjuvant were administered to sheep and rabbits from which antiserums were then prepared. The different vaccines were evaluated by comparing the in vitro bactericidal activity of the sheep and rabbit antiserums. Results of the in vitro tests were compared to the protection induced in vaccinated ewes which were orally exposed to C fetus. The sheep and the rabbit antiserums after they were heated at 56 C for 30 minutes were unable to exert a killing effect on C fetus cells. Addition of a fresh homologous complement source to the heated antiserums was necessary to demonstrate the in vitro bactericidal capacity. In the comparison of the suspect and the efficacious commercial bacterins, which both reportedly contain serotype C cells, there was a statistically significant difference in bactericidal activities for serotype C cells of antiserums from sheep 14 days after the 2nd vaccination. There was a corresponding significant difference in the antiserums from rabbits 14 days after the 2nd vaccination. Proportionally, more abortions and stillbirths were observed in the ewes vaccinated with the suspect bacterin and then orally exposed to C fetus-serotype C cells than in those vaccinated with the efficacious bacterin. The results indicated that the ability of vaccinated sheep to overcome infection is reflected in the in vitro bactericidal capacity of antiserum from the animal. Since 89% of the variation in sheep antiserums from 14 days after 2nd vaccination can be accounted for by rabbit antiserums from 14 days after 2nd vaccination, the in vitro bactericidal capacity of rabbit antiserums probably provides a reliable index of the protective effect of bacterins containing serotype C for ewes exposed to the homologous serotype.

Antibody-mediated immobilization of Campylobacter fetus: inhibition by a somatic antigen

Immobilization tests were conducted on a wild-type strain of Campylobacter fetus subsp. intestinalis and on a mutant lacking an antiphagocytic cell surface component. Highly effective immobilization of the mutant, both as single cells and clumps of cells, was produced with an antiserum containing antibodies specific for the flagellar hook and filament and for the O antigen. Damage to flagellar hooks after reaction with this antiserum was observed only with cells of the mutant. Single-cell immobilization of the mutant was also produced with an antiserum specific for a heat-stable somatic antigen which was distinct from the O antigen and was exposed on the cell surface only of the mutant. Minimal immobilization of the wild strain was brought about by either of these antisera. It was shown also that O antibodies had no effect on the motility of either the wild strain or mutant. These findings indicate that antibody-mediated immobilization may be brought about by effects on the flagellar hook or cell body, as well as on the flagellar filament. Furthermore, the protection from immobilization afforded the bacterium by the antiphagocytic surface structure suggests a dual function for this virulence factor in the infected animal.

Immunisation of cattle against vibriosis with vaccines prepared from Campylobacter fetus subsp fetus

Subcutaneous administration of vaccines prepared from cells of Campylobacter fetus subsp fetus strain A28 to heifers gave substantial protection against infertility due to C. fetus subsp venerealis strain B6. Strains A28 and B6 had different heat-stable antigens and conformed respectively to serotype B and serotype A of Berg et al (1971). The results suggested that the protective antigens were heat-labile antigens common to both strains. Although vaccines prepared from serotype B strains of C. fetus subsp fetus could be used to immunise cattle against vibriosis, the results did not suggest that their use in preference to those prepared from C. fetus subsp venerealis would offer any advantages.