Some antigenic properties of cultured cell and bacteroid forms of fast- and slow-growing strains of Lotus rhizobia.

Immunodiffusion cross-reactions of 62 fast- and 76 slow-growing of Lotus rhizobia with antisera to four of the fast-growing and five of the slow-growing strains were studied. No sharing of antigens by both fast- and slow-growing strains was found. Somatic antigens were very strain specific with only eight of the fast-growing and five of the slow-growing strains tested having somatic antigens identical to those of one or more of the strains of the same group used for antisera production. In contrast, internal antigens were shared by all fast-growing strains and with seven exceptions by all slow-growing strains. Antigens of cultured rhizobia, and bacteroids from nodules formed on different legumes by the same strain of Rhizobium, were similar. However, incontrast to cultured cells, bacteroids generally required no pretreatment (heat or ultrasonic disruption) to give a strong somatic antigen reaction in immunodiffusions.     

Antigenic Relationships Among the Proteolytic and Nonproteolytic Strains of Clostridium botulinum

Relationships of the somatic antigens among Clostridium botulinum strains have been investigated by tube agglutination and agglutinin absorption tests. Results revealed a relationship by which strains of C. botulinum are grouped by their proteolytic capacity rather than by the type of specific toxin produced. Thus, C. botulinum type E and its nontoxigenic variants, which are nonproteolytic, share common somatic antigens with the nonproteolytic strains of types B and F. Absorption of antiserum of a strain of any one type with antigen of any of the others removes the antibody to all three types. In the same manner, C. botulinum type A shares somatic antigens with the proteolytic strains of types B and F, and absorption of any one antiserum with an antigen of either of the other two types removes the antibody to all three types. Partial cross-agglutination of C. sporogenes, C. tetani, and C. histolyticum with the somatic antisera of the proteolytic group was also observed.     

Investigation of the incidence of influenza A viraemia caused by virus strains circulating among children in 1968 - 1977.

Nineteen strains of Type A influenza virus isolated from the blood of small children in 1968--77 were studied. The investigation of the strains in HAIR with antisera to the antigenic components of the strains in HAIR with antisera to the antigenic components of the strains A/Hong-Kong/68,A/Anglia/72, A/Port Chalmers/73 and A/Victoria/75 made it possible to demonstrate antigenic "drive" of the haemagglutinin in the years 1968--1977 and to divide the strains into 4 varieties. A high sensitivity to inhibitors was observed in all the strains isolated. The study of pathogenicity and toxicity of the strains revealed viraemia in the strains isolated during the 1972--1973 epidemic and the subsequent epidemics with the absence of pathogenicity and toxicity for white mice. Regular finding of viraemia coincided in time with increased thermostablty of the haemagglutnin in the strains under study.     

Serological Studies of Clostridium botulinum Type E and Related Organisms II. Serology of Spores

Pure spore antigens for the immunization of rabbits were prepared by enzymic digestion of vegetative components and separation of the cleaned spores in polyethylene glycol. Spore antisera were prepared to strains representative of toxigenic Clostridium botulinum type E; nontoxigenic boticin E-producing variants; nontoxigenic nonproducers of boticin E; nontoxigenic "atypical" strains, which differ somewhat from C. botulinum type E in their physiology; C. botulinum types A and B; and C. bifermentans. They were tested against these and additional strains representative of the above groups, other types of C. botulinum, and other Clostridium species. There was no evidence of agglutination of flagellar or somatic antigens of vegetative cells by these antisera. Agglutination and agglutinin absorption tests showed common antigens among toxigenic type E strains and nontoxigenic variants, both producers and nonproducers of boticin E. Some nontoxigenic "atypical" strains varied in their ability to be agglutinated by type E antisera, and others did not agglutinate at all. Of those atypical strains that were not agglutinated, one was agglutinated by C. bifermentans antiserum. Antisera prepared against C. botulinum types A and B and C. bifermentans did not agglutinate the spores of type E or its variants nor share antigens common to each other. Similarly, antisera to type E, its nontoxigenic variants, and nontoxigenic atypical strains did not agglutinate other C. botulinum types or any other Clostridium species investigated.     

Differentiation of Erwinia carotovora subsp. carotovora and Erwinia carotovora subsp. atroseptica isolated from potato by Western blot and subsequent indirect ELISA

Electrotransfer of protein bands from a polyacrylamide gel to a hydrophobic poly-vinylidene difluoride (PVDF) membrane (Western blot) and their serological determination by indirect ELISA (immunoblotting) were used to differentiate Erwinia carotovora subsp. carotovora (Ecc) from Erwinia carotovora subsp. atroseptica (Eca). Ninety strains: 69 Ecc, 19 Eca and two Erwinia chrysanthemi (Echr) were examined. Eight polyclonal antisera against whole cells, glutaraldehyde fixed cells, glycopro-teins, and somatic antigens were prepared. Antisera produced with glutaraldehyde fixed cells did not recognize any band of the protein pattern. The remaining antisera recognized a limited number of bands. Two protein bands allowed differentiation of the two subspecies by the antisera against glycoproteins. One band with an estimated molecular weight of 36000 Da was present in the 19 Eca strains tested and another band with an estimated molecular weight of 35 000 Da was present in the 69 Ecc strains, except for three cases. The strains of Echr showed a band with an estimated weight of 33 000 Da.     

Application of immunoprecipitation in agar gel for the serological typing of soybean root-nodules

The results of serological typing of root-nodule homogenates from soybean plants inoculated by mixed bacterial inocula under field and greenhouse conditions are submitted. The inocula were prepared from strains capable of serological differentiation on the basis of their somatic antigens. Individual root-nodule homogenates were typed serologically by immunoprecipitation in agar with antisera against the inoculum strains. This method gave accurate determination of the origin of 605 out of a total of 616 serologically typed root-nodules and of the individual bacterial strains which participated in their formation.     

Serological studies on Listeria grayi and Listeria murrayi

A cross-agglutination study between somatic antigens from reference strains of Listeria grayi and Listeria murrayi with rabbit antisera was done. L. murrayi antisera reacted, at low titres, with L. grayi but L. grayi antisera did not react with L. murrayi antigen. These results, together with agglutinin-absorption tests, led to the conclusion that the serologic relationship between L. grayi and L. murrayi is not as close as is thought. The two species seem to differ in at least one somatic factor, that might be designated O-XVI for L. grayi and O-XVII for L. murrayi. The serologic relationship of L. grayi and L. murrayi with other serovars of Listeria is discussed. The agglutination titre of 180 healthy ruminants against O-antigens of L. grayi and L. murrayi was also investigated; almost all the sera reacted with the antigens of these species, with similar titres (that reached 640) to those detected against O-antigens of serogroups 1/2 and 4.     

Serological studies on Listeria grayi and Listeria murrayi

A cross-agglutination study between somatic antigens from reference strains of Listeria grayi and Listeria murrayi with rabbit antisera was done. L. murrayi antisera reacted, at low titres, with L. grayi but L. grayi antisera did not react with L. murrayi antigen. These results, together with agglutinin-absorption tests, led to the conclusion that the serologic relationship between L. grayi and L. murrayi is not as close as is thought. The two species seem to differ in at least one somatic factor, that might be designated O-XVI for L. grayi and O-XVII for L. murrayi. The serologic relationship of L. grayi and L. murrayi with other serovars of Listeria is discussed. The agglutination titre of 180 healthy ruminants against O-antigens of L. grayi and L. murrayi was also investigated; almost all the sera reacted with the antigens of these species, with similar titres (that reached 640) to those detected against O-antigens of serogroups 1/2 and 4.     

THE PHYSIOLOGICAL AND SEROLOGICAL PROPERTIES OF STREPTOCOCCUS BOVIS AND RELATED ORGANISMS ISOLATED FROM CATTLE AND SHEEP

The physiological and serological properties of 153 strains of Streptococcus bovis isolated from cattle and sheep have been studied. With 12 specific antisera it was possible to type 75 of the isolates. Neither the fermentation of arabinose nor of raffinose was related to type specificity. The only strain fermenting mannitol was serologically distinct from all the other strains, and the type antigen was probably located on the cell wall whereas with the other 11 types it was capsular.
The distribution of these types in cattle and sheep has been determined together with their changes in individual cows sampled on three occasions over 18 months.     

Comparative study of Agrobacterium biotypes 1, 2 and 3 by electrophoresis and serological methods

A comparative study by electrophoresis and serology of strains representing the three Agrobacterium biotypes was carried out. Thirteen Spanish isolates and strains from international collections were included. Ten antisera were prepared by using strains from the three biotypes and different types of antigens. The strains were studied by immunodiffusion, indirect immunofluorescence and indirect ELISA. Serological relationship among all the strains was observed, although serological heterogeneity within each of the biotypes occurred. Biotype 3 appears as serologically related to biotypes 1 and 2, having an intermediate position. This observation is in agreement with their biochemical characteristics. Electrophoretic analysis of the three biotypes showed that there was high variability. Three main bands appeared in the six strains studied. One specific band occurred in the biotype 1 strains and another in the biotype 3 strains.     

Common Antigenic Determinant in a Rumen Organism and in Salmonellae Containing the Antigen O4

Nineteen of 28 strains of rumen organisms isolated from a cow on a high roughage diet and identified morphologically as butyrivibrios, reacted to a low agglutinin titer with salmonella antisera, forming five groups. However only one strain reacted with polyvalent O salmonella antiserum. This strain reacted with O4 factor serum and with antisera to Salmonella strains containing the antigen O4, and agglutinin absorption tests showed the presence of an antigen identical to O4. When 16 further strains of butyrivibrio-like rumen organisms isolated from three cows and one steer were examined, one possessed an antigen similar to but not identical with the antigen O9, and two strains reacted with specific O6,7 factor serum but were not examined further. These four strains were presumptively identified by physiological tests as butyrivibrios. The possible site of antigenic stimulation by such organisms is discussed.     

Serogrouping of Rhodococcus equi

The serological relationships among 27 isolates of Rhodococcus equi selected from a total of 1,195 isolates were investigated by cross-agglutination and absorption tests. The presence of capsular material was demonstrated in all the 27 isolates by electron microscopic observation. Antisera were prepared by employing formalized antigen of each isolate. In the cross-agglutination test with formalized antigen, 13 antisera reacted with homologous antigens alone, but the remaining 14 antisera reacted not only with homologous antigens but also with one to four heterologous antigens. When these 14 antisera possessing heterologous agglutinins were absorbed with each of the cross-reacting antigens, 14 specific antisera were obtained. The cross-agglutination test with these 27 antisera proved the 27 strains examined to be serologically distinct from one another. These strains were designated serogroups 1 to 27. Thus the same number of grouping antisera were prepared. The distribution of each serogroup among the 1,195 isolates and 15 reference strains was investigated by the slide agglutination test. All the strains were found to be groupable. Most of them belonged to serogroups 1 to 4, 7 to 9, 11, 14, and 15. Of the serogroups designated, 4, 16, 2, 12, 21, 1, and 9 were identical with Prescott's serovars 1, 2, 3, 4, 5, 6, and 7, respectively.     

Production of Multivalent Fluorescent Antisera for Identification of Organisms in the Mycobacterium avium-Mycobacterium intracellulare Complex

Antisera to ten strains of mycobacteria in the Mycobacterium avium-Mycobacterium intracellulare group were obtained by injecting rabbits with ultraviolet light-killed cells. The antisera were conjugated with fluorescein isothiocyanate and used in the direct fluorescent antibody test. Individual antisera reacted specifically with the mycobacterial serotype used to produce them. The antisera were then combined in two multivalent pools. Each multivalent pool reacted specifically with its corresponding antigens. The multivalent antisera were thus found to provide a rapid identification method for the mycobacteria studied.     

Polysaccharides and their common proteinic carrier in the Vi antigens of Citrobacter ballerup and Salmonella typhi Ty2

Immunochemical analysis of Citrobacter ballerup and Salmonella typhi Ty2 showed that the strains share native and heat-resistant proteins that are, apparently, the carriers of a common polysaccharidic determinant present in their respective somatic antigens. After the classic acetic acid hydrolysis, the somatic antigen of C. ballerup reacted, in agar gel, against the homologous antiserum by two precipitation lines, one of which also precipitated against the anti S, typhi Ty2 serum; the hydrolysis of the S. typhi Ty2 somatic antigen demonstrated that, in addition to the 'O' polysaccharide, reacting against all the S. typhi antisera, it contains a polysaccharide that precipitated against the anti-C. ballerup serum. The elusiveness in the agglutinability of only freshly isolated bacterial authorizes some doubt concerning the responsibility of the antipolysaccharide antibodies in the agglutinating Vi sera; in order to induce anitpolysaccharides hyperimmunizations are needed while antiproteins are easily induced by short immunizations.     

Serological Studies of Clostridium botulinum Type E and Related Organisms

Clostridium botulinum type E antigens prepared from washed cells by either Formalin treatment or heating at 100 C were used for immunizing rabbits. Agglutination tests showed that high levels of antibody were produced by both types of preparations. Flagellar antigens were highly strain-specific, whereas the somatic antigens were sufficiently similar to produce complete cross-agglutination. One toxigenic strain produced toxigenic and nontoxigenic progeny which were physiologically and antigenically identical in all other respects. Other nontoxigenic strains whose growth, physiological, and morphological characters were identical to type E and strains which had some physiological differences completely cross-agglutinated with type E strains via the somatic antigen. Neither type of antiserum agglutinated other clostridia against which they were tested except for C. acetobutylicum. This reaction seems to be due to a nonspecific anamnestic response and does not appear to be related to the immunizing strains. The nontoxigenic strains studied seem to have no greater antigenic differences from type E strains than the type E strains have from each other.     

Serologic differences in strains of Sporothrix schenckii.

To obtain evidence that Sporothrix scheneckii enters the body by contact with contaminated materials, the antigenic property of strains from different sources was investigated. The reciprocal absorption test of the antisera against a soil isolate and a human isolate (KO 4606) showed that the absorbed antisera against KO 4606 possessed unique antigen(s) in addition to the common antigen of both strains. Twenty-three clinical isolates were tested with absorbed antisera. Not all of them possessed the unique antigen(s), but there were serologic varieties among S. schenckii strains, regardless of their sources, clinical type of the disease and the morphology of the yeast phase cells.     

Identification of Streptococcus Agalactiae by the Fluorescent Antibody

A fluorescent antibody technic for identification of Streptococcus agalactiae is described. Smears from colonies on blood agar plates were tested. A pool of conjugates to four different Streptococcus agalactiae antisera stained all the 80 Streptococcus agalactiae strains investigated. The pool proved superior to individual conjugates. Also strains of groups C and G were stained by the Streptococcus agalactiae conjugates. These, however, could be differentiated from Streptococcus agalactiae strains by examination of the controls because the conjugates of antisera to some group C strains stained group C and G strains but not Streptococcus agalactiae strains.     

Characterization of Ornithine Decarboxylase-Positive, Nonmotile Strains of the Klebsiella-Enterobacter Group

Thirty-seven strains of ornithine decarboxylase-positive, nonmotile Klebsiella-Enterobacter organisms isolated from 36 patients were studied by biochemical and serological testing. Five strains gave biochemical reactions which conformed closely to those of Escherichia coli; three strains gave positive Quellung reactions to specific Klebsiella antisera. (Two of these were thought to be Enterobacter in spite of this typing reaction.) The remaining 29 strains were classified as Enterobacter. These results demonstrate the necessity of doing both an ornithine decarboxylase test and a motility test to differentiate Klebsiella from Enterobacter. Had only a motility test been done, they all would have been called Klebsiella.     

Vero cytotoxin production and presence of VT genes in Escherichia coli strains of animal origin

Vero cytotoxin (VT) production has been studied in 34 Escherichia coli strains isolated from animals with enteric diseases. The strains were tested by DNA hybridization with probes for VT1 and VT2 sequences and also in toxin neutralization experiments with specific antisera. Twenty bovine strains, belonging to nine different O serogroups, produced VT1 or VT2 but not both toxins. In contrast, all 14 porcine strains of four different O serogroups produced VT2 only. Six of these porcine strains, belonging to serogroups O138, O139 and O141, were isolated from cases of oedema disease. In general, the porcine isolates produced toxin at a lower level than the bovine strains.     

Polyclonal Antisera To Distinguish Strains and Form Variants of Photorhabdus (Xenorhabdus) luminescens

In this study antisera against Photorhabdus luminescens strains were prepared for the first time. P. luminescens is a bacterial symbiont of entomopathogenic nematodes belonging to the genus Heterorhabditis. To characterize P. luminescens strains and form variants, we produced polyclonal antisera against P. luminescens PE (obtained from nematode strain NLH-E87.3) and against the primary and secondary forms of P. luminescens PSH (obtained from nematode strain DH-SH1). In double-diffusion tests all form variants of strain PE reacted with the antiserum against the primary form, but each variant produced a different diffusion pattern. The primary and secondary forms of strain PSH were also serologically different. Antiserum 9226 reacted with almost all P. luminescens strains tested, but it reacted differently with each strain in the double-diffusion test, showing that the strains were serologically different. The specificity of the antisera was increased by cross-absorption. After cross-absorption the antiserum against the strain PSH primary or secondary form was specific for that form and did not react with the other form. Using the cross-absorbed antisera in immunofluorescence cell-staining tests, we could distinguish primary and secondary form cells in a mixed strain PSH culture.