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PubMed2000

Evaluation of three newly developed enzyme-linked immunosorbent assays and two agglutination tests for detecting Salmonella enterica subsp. enterica serovar dublin infections in dairy cattle.

In this study test characteristics of three newly developed enzyme-linked immunosorbent assays (ELISAs) for Salmonella enterica subsp. enterica serovar Dublin were evaluated and compared with two agglutination tests. The ELISAs involved were an indirect ELISA with serovar Dublin lipopolysaccharide (LPS ELISA), an indirect ELISA with serovar Dublin flagellar antigen (GP ELISA), and a double-antibody sandwich blocking ELISA that uses monoclonal antibodies against S. enterica subsp. enterica serovar Enteritidis flagellin (GM-DAS ELISA). The agglutination tests involved were two routine serum agglutination tests with either somatic (O) or flagellar (H) antigen. Diagnostic specificity of the three ELISAs was determined using 840 serum samples from seven dairy herds without any history of serovar Dublin infection. Cutoff values at a titer of 100, 100, and 10, respectively, for the LPS ELISA, GP ELISA, and GM-DAS blocking ELISA resulted in a specificity of 99.3, 100, and 100%, respectively. Using these cutoff values the LPS ELISA, GP ELISA, and GM-DAS ELISA were able to detect, respectively, 30, 46, and 38% of 50 fecal culture-positive animals from 13 herds with a recent serovar Dublin infection. With the same cutoff values, active carriers (n = 18) were detected for 94.4% with the LPS ELISA and for 100% with the GP and GM-DAS ELISAs. Kappa values determined on the results of all tests from 8 of the 13 serovar Dublin-infected herds and the 7 control herds demonstrated a good correlation between the results of all ELISAs and the H-agglutination test. The results of the O-agglutination test failed to correlate with those of the other tests. Using a set of sera from 170 aborting cows (with 25 abortions due to serovar Dublin), test results of the ELISAs and the H-agglutination test were comparable. The H-agglutination test may be used successfully for single sample testing, especially to diagnose abortion due to serovar Dublin. It is concluded that the ELISAs are useful diagnostic tools in serovar Dublin control programs and that they are preferred to agglutination tests for reasons of automation and costs.

Abortion, Veterinary↗
PubMed1981

Concanavalin A agglutination assays in the multistage transformation of a pig cell line.

Cells of a pig Fallopian tube line were agglutinated by concanavalin A (Con A). Similar ConA agglutination was shown in diploid and nontumoral transformed cells with one (T1) translocation until the 112th subculture. Then a progressive increase of agglutination was shown until the 149th subculture and the rate of agglutination remained constant thereafter. The progression of ConA agglutination paralleled the progression of anchorage independence. The highest ConA agglutination occurred when anchorage independence was well established and persisted until the 193rd T1 subculture when benign tumorigenicity was demonstrated. After the appearance of the second translocation (T2), the self-agglutination of the cells was directly related to malignancy and to high tumor incidence in mice. Anchorage independence and the highest ConA agglutination were directly related to benign transformation and indirectly related to malignant transformation of the pig Fallopian tube cell line.

Agglutination↗
PubMed1978

Changes in concanavalin A agglutinability during development of the inner cell mass and trophoblast of mouse blastocysts in vitro.

Mouse blastocyst cultures were analysed for Concanavalin A (Con A) agglutinability by microhaemadsorption methods and for Con A binding capacity with Rhodamine-Con A stain. The inner cell mass, which was not agglutinable in the early culture stages, became agglutinable when it started to develop. The trophoblast, which was initially agglutinable, lost this property as the cells matured. There was no apparent correlation between changes in agglutinability and capacity to bind Rhodamine-Con A. The pattern of change in Con A agglutinability which characterized development of the inner cell mass and trophoblast is consistent with an interpretation that agglutinability was related to the migratory activities of these cells. The loss of agglutinability associated with trophoblast maturation may have been due to alterations in Con A receptor accessibility.

Agglutination↗
PubMedDate not supplied

Study of strains agglutinable with enteroinvasive anti E. coli polyvalent sera isolated from ill and healthy subjects for optimizing the laboratory diagnosis of diarrhoea.

369 E. coli strains that are agglutinated in A or B anti E. coli enteroinvasive (EIEC) polyvalent sera and inducing no keratoconjunctivitis in the guinea pig's eye have been selected. The biochemical reactions of E. coli strains that can be agglutinated in A or B EIEC polyvalent sera occupy an intermediary position between those of Shigella genus and the classical features of Escherichia, i.e.; 87% are motile bacteria, 88%--ferment lactose, 81% form acid from sodium mucate and lysine is not decarboxylated by 87% of the strains. As for the antigenic behaviour with 15 out of the 16 sera employed, the strains under consideration have agglutinated by slide test in one or several sera, with varying intensities. None of the strains agglutinated on slide in the O164 antiserum. Subsequently, agglutinations have been performed in tubes only with the strains that agglutinated on the slide with a +3 or +4 intensity. Out of the 369 strains under consideration only 25 have agglutinated in the tube, all the false positive reactions representing 6.7%. The data presented lead to the conclusion that such strains that have been isolated from ill or healthy patients cannot be considered as pathogenic diarrhoea agents, the differentiation from the invasive strains (in the absence of the guinea pig for the pathogenicity test) cannot be made on the basis of the biochemical reactions, but only by means of a set of monovalent sera and by performing the tube agglutination tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗
PubMed2005

[Preparation and characterization of non-agglutinating mAbs against membrane antigen on human erythrocytes].

AIM: To prepare monoclonal antibodies (mAbs) against membrane antigens on human erythrocytes and characterize their properties. METHODS: BALB/c mice were immunized with the membrane antigens of human type O erythrocytes. The splenocytes of the immunized mice were fused with Sp2/0 myeloma cells by hybridoma technique. The antibodies to common antigen on human erythrocytes were screened by hexadimethrine bromide (polybrene) test tube method and then the agglutinating antibodies (complete antibodies) were weeded out by slide hemagglutination assay. The hybridoma cells secreting non-agglutinating antibodies (incomplete antibodies) were cloned by limiting dilution method. The stability of the obtained hybridoma cells and the properties of the mAbs were identified. RESULTS: One hybridoma cell 2E8 was obtained, which secreted non-agglutinating antibody. The mAb 2E8 belonged to IgG1, could agglutinate H antigen, and had no species cross-agglutination reaction. The titers of culture supernatant and ascites of 2E8 were 1:1,024 and 1:64x10(6), respectively. When the affinity of mAb 2E8 was evaluated by agglutination reaction, erythrocytes began to agglutinate after 7 seconds and the clots exceeded 1 mm(2) in 3 minutes. CONCLUSION: The non-agglutinating mAb against H antigen was prepared successfully. The mAb 2E8 has good titer, affinity and specificity, which lays the foundation for preparation of bispecific antibodies (BsAb).

Agglutination↗
PubMed1991

Detection of toxoplasma-specific immunoglobulin-G: assessment of a slide agglutination test.

The performance of a slide agglutination test for detection of toxoplasma-specific IgG was assessed and compared with that of the dye test and latex agglutination test. The slide agglutination test was as sensitive as, and more specific than, latex agglutination. The predictive value of a negative slide agglutination test was less than the latex agglutination test but produced results within minutes, although quantitative results were not comparable to other assays. Slide agglutination presents a rapid alternative to the latex agglutination test as a screening assay for toxoplasmosis, although patients at risk of life-threatening infection require detailed serological examination using additional methods.

Agglutination Tests↗
PubMed1977

Specific agglutination of Escherichia coli O128B12 by the mannose-binding proteins of Pseudomonas aeruginosa.

The mannosephilic haemagglutinins of Pseudomonas aeruginosa were found to agglutinate cells of Escherichia coli O128B12, to be adsorbed onto them and to attach peroxidase to them. These reactions were specifically inhibited by D-mannose. No agglutination by this Pseudomonas haemagglutinin was obtained when several other enteropathogenic types of Escherichia coli and some other Gram-negative bacteria were examined. Concanavalin A, which also reacted with Escherichia coli O128B12 cells, interacted with some of the other bacteria examined, too. Escherichia coli O128B12 was not agglutinated by the Pseudomonas galactosephilic haemagglutinins and those of the plant Phaseolus vulgaris. Its maximal agglutination by the Pseudomonas mannosephilic haemagglutinins was obtained employing cells grown for 4-6 h in conventional media. The growth temperature, aeration and presence of certain amino acids, but not D-mannose, in the culture medium had some effect on the agglutination in tensity; pH 6-8 was optimal for it and only at pH 3.0-3.2 no agglutination was observed. Treatment of the bacteria by proteolytic enzymes, ethanol or formaldehyde did not alter their agglutinability by either the Pseudomonas lectin or by antibodies produced against them in rabbits. Heating of the bacteria to 100 degrees C prevented their agglutination by the Pseudomonas lectin and lowered their ability to adsorb it, but did not significantly affect their reactions with the rabbit antibodies.

Agglutination↗
PubMed1984

Alpha-mating-type-specific suppression and a-mating-type-specific enhancement by tunicamycin of sexual agglutinability in the yeast Saccharomyces cerevisiae.

Effects of tunicamycin (TM) on the sexual agglutinability and zygote formation of Saccharomyces cerevisiae were studied using the two kinds of haploid strains, inducible and constitutive for sexual agglutinability. Induction of sexual agglutinability by opposite mating type sex pheromone of inducible strains was inhibited by TM in alpha mating type but not in a mating type. The recovery by temperature-shift-down from the temperature-suppressed sexual agglutinability of constitutive strains was enhanced by TM in a mating type but rather inhibited in alpha mating type. Pretreatment with TM of constitutive strains enhanced sexual agglutinability in a mating type but not in alpha mating type. The above-mentioned a-mating-type-specific agglutinability-enhancing actions of TM were discussed in relation to the action mechanism of alpha pheromone which induces or enhances the sexual agglutinability of a cells. Zygote formation was inhibited by TM in both constitutive and inducible strains at concentrations which showed only partially inhibitory effect on sexual agglutinability.

Genotype↗
PubMed1961

Studies on thrombin-induced platelet agglutination.

A one-stage macroscopic test for platelet agglutination was used to study the effect of thrombin and thrombin-cation mixtures on washed platelets. Conclusions regarding platelet agglutination are as follows: (a) Canine, bovine, or human thrombin alone does not cause agglutination of canine or human platelets. (b) Thrombin with calcium or magnesium causes rapid platelet agglutination. Both calcium and magnesium are active at physiologic concentrations. Divalent manganese or cadmium ions can be substituted for calcium or magnesium. (c) The agglutination reaction is affected but little by the species of origin of thrombin or platelets, or by variations in ionic strength or pH over a broad range. (d) Temperature at which the reaction is carried out is critical; optimal temperature for the test is 28 degrees C. (e) Agglutination is inhibited by high ionic strength, by pH values outside the range 6.4-8.6, and by temperatures outside the range 25-28 degrees C. High concentrations of calcium have a specific inhibitory effect. (f) Platelet agglutination time is as sensitive an index of thrombin concentration as is the fibrinogen clotting time. A comparison is made between divalent cations which influence platelet agglutination induced by thrombin, TAg', and TAg. A similar comparison is made of cations influencing the action of thrombin on the "substrates," fibrinogen, TAMe, and platelets.

Animals↗
PubMed1987

Characterization of a rat salivary sialoglycoprotein complex which agglutinates Streptococcus mutans.

Rat saliva agglutinated Streptococcus mutans Ingbritt and NCTC 10449 and Streptococcus sanguis NCTC 7864 but not S. mutans NCTC 10921, GS 5, or LM 7, Streptococcus sobrinus 6715-13 or OMZ 65, or Streptococcus cricetus HS 6, as measured turbidometrically. The specificity of agglutination by rat saliva was the same as that by human saliva. Agglutination was associated with a mucin complex (rat salivary agglutinin complex [rS-A]) of sulfated sialoglycoproteins, with a trace of associated lipid and an apparent Mr of 1.6 X 10(6), isolated by gel-filtration Fast Protein Liquid Chromatography. The complex was dissociated in a high-ionic-strength buffer containing 6 M urea and then fractionated by gel filtration and anion-exchange Fast Protein Liquid Chromatography into four sulfated sialoglycoprotein components, designated rS-A-1Q1, rS-A-1Q2, rS-A-1Q3, and rS-A-2, with rS-A-1Q2 being polydisperse through differential glycosylation of the polypeptide backbone. The dissociation destroyed agglutination activity. The polypeptide backbones contained up to 42% serine plus threonine and up to 40% glycine plus alanine plus proline plus valine. The carbohydrate moiety of the rS-A sialoglycoproteins consisted of N-acetylgalactosamine, sialate, galactose, fucose, N-acetylglucosamine, and small amounts of mannose, with the predominant sugar being N-acetylgalactosamine. Agglutination was inhibited by 1 mM EDTA but was restored by 1.5 mM CaCl2. Agglutination was also inhibited by 5 mM CaCl2; nonimmune sera; cationic polymers; and wheat germ, lentil, soybean, and peanut lectins. However, agglutination was not affected by lipoteichoic acid, various anionic proteins, or various sugars. Neuraminidase treatment of rS-A did not affect activity, but tryptic digestion of S. mutans did prevent agglutination. The results are consistent with calcium bridging the negative groups within the rS-A complex and allowing the approach of rS-A to the bacterial cell surface to effect a specific conformational attachment.

Agglutinins↗
PubMed1985

Detection of cytomegalovirus antibody with latex agglutination.

Transfusion-acquired cytomegalovirus (CMV) infections should be prevented in seronegative immunocompromised patients by providing blood products from donors who are also seronegative. Latex agglutination was investigated as a simple and rapid method for detecting antibody against CMV. Latex beads were coated with CMV antigen, incubated for 8 min at room temperature with 25 microliter of sera, and examined for agglutination. The sensitivity and specificity of latex agglutination was compared with that of indirect hemagglutination (IHA, Cetus Corp., Emeryville, Calif.) and enzyme immunoassay (EIA) with sera from 604 random blood donors or patients. Of 327 serum samples shown to be seronegative by EIA and IHA, 327 had a latex agglutination titer of less than 1:4 (specificity, 100%). Of 236 serum samples with detectable antibody by EIA and IHA, 228 had a latex agglutination titer of 1:4 or greater (sensitivity, 97%). Plasma collected with EDTA, heparin, or citrate was satisfactory for latex agglutination. Latex agglutination results correlated quantitatively with those of EIA, and the test also detected fourfold or greater rises in antibody with paired sera from six patients with posttransfusion CMV infections. Latex agglutination is a sensitive and specific assay that is rapid and simple to perform and should be effective in selecting seronegative blood donors to prevent posttransfusion CMV infections in seronegative recipients.

Antibodies, Viral↗
PubMed1989

Latex agglutination test for diagnosing pneumococcal pneumonia in children in developing countries.

OBJECTIVE: To prepare and assess the sensitivity and specificity of a latex agglutination test specific for the serotype of antigen in diagnosing pneumococcal pneumonia in Gambian children. DESIGN: Comparison of agglutination test specific for serotype with culture of blood and lung aspirates, countercurrent immunoelectrophoresis, and commercial latex agglutination tests in diagnosing pneumococcal pneumonia. Cross reaction studies and investigation of 102 control children to determine specificity of agglutination test specific for serotype. SETTING: General medical ward of Medical Research Council laboratories, The Gambia. PATIENTS: 101 Gambian children aged between 2 months and 10 years admitted with severe pneumonia. INTERVENTIONS: Serum samples were boiled and treated with edetic acid, and urine samples were boiled and concentrated 25 times before testing. END POINT: A latex agglutination test specific for the serotype of pneumococcal antigen that is sensitive and highly specific for detecting pneumococcus in the urine of patients with pneumococcal pneumonia. MEASUREMENTS AND MAIN RESULTS: Concentrated urine samples from 16 of the 21 children (76%) with pneumococcal pneumonia established by results of culture of blood or lung aspirates gave a positive result with the agglutination test specific for serotype, whereas only four of the 102 urine samples obtained from control children without pneumonia gave positive results. The serotypes of antigens detected in the urine of children with pneumococcal pneumonia and the serotypes of pneumococci isolated from cultures of blood or lung aspirates were the same in all cases. CONCLUSIONS: When performed on urine samples the agglutination test specific for serotype has a high specificity and is more sensitive than culture of blood or lung aspirates, commercial agglutination tests, or countercurrent immunoelectrophoresis in identifying pneumococcal pneumonia. It is easy to use and should be especially useful in communities with limited laboratory facilities.

Antigens, Bacterial↗
PubMed1995

Use of the Pastorex aspergillus antigen latex agglutination test for the diagnosis of invasive aspergillosis.

AIMS: To evaluate the Pastorex aspergillus antigen latex agglutination test for the diagnosis of invasive aspergillosis in patients undergoing liver or bone marrow transplantation. METHODS: Serum samples were taken at least twice weekly post-transplant and tested for Aspergillus antigen. Latex agglutination test results were compared with microbiological examination of respiratory, urine and bile specimens. Serum samples from liver transplant patients were also tested for antibodies to Aspergillus fumigatus by counter immunoelectrophoresis. RESULTS: Eight of the 91 patients studied developed invasive aspergillosis. Positive latex agglutination tests were obtained in eight of 187 (4.3%) serum samples from four of these eight patients. The other four patients with invasive aspergillosis gave consistently negative latex agglutination tests. A positive latex agglutination test was the first indication of invasive aspergillosis in two patients; these patients were already on amphotericin B. Positive latex agglutination tests were the only evidence of invasive aspergillosis in one patient who subsequently died of the infection. False positive latex agglutination tests were obtained in five of 83 (6%) patients with no evidence of invasive aspergillosis and misleading positive cultures seen in nine of 83 (10.8%). No antibodies were detected in three of four liver transplant patients with invasive aspergillosis. Conversely, antibodies were detected in 63 of 262 (24%) serum samples from 43 liver transplant patients with no evidence of invasive aspergillosis; one of these patients had an antibody titre of 1:2 on four separate occasions. CONCLUSIONS: The Pastorex aspergillus antigen latex agglutination test, when used alone, lacks sensitivity and specificity for the early diagnosis of invasive aspergillosis. A diagnosis was made in all patients with invasive aspergillosis when both culture and antigen tests were performed although using these criteria a false positive diagnosis would have been made in 13 of 83 (15.6%) patients. Microbiological and serial serological investigations for antigen should both be performed and the results considered in conjunction with radiological and clinical evidence.

Aspergillosis↗
PubMed1985

[Detection in bovine serum of non-agglutinating antibodies directed against occult antigens of Brucella abortus strain 19].

Injection of different animal species with particulate T-dependent antigens induces the appearance of two antibody populations belonging to IgG class, one of them with agglutinating activity and the other lacking this capacity, that is, non-agglutinating. In this paper, 3 adult female Hereford were inoculated subcutaneously, fortnightly, four times, with 5 x 10(10) heat killed smooth S19 Brucella abortus cells. Blood samples were taken ten days after the last inoculation and were individually processed. Serum agglutinating titres against the homologous antigen and the Coombs test score were similar, indicating that nonagglutinating antibody titres directed against surface antigens of the smooth phase were not significant (Table 1). When sera were incubated with a suspension of Brucella abortus S45/20 (a rough strain) they showed poor agglutinating ability, but they contained non-agglutinating activity at high level, as determined by the anti-gamma-globulin test (Table 1). Similar results were obtained when the same sera were adsorbed with Brucella abortus S19 up to elimination of the antibodies directed against surface antigens, and then incubated with a suspension of strain 45/20 (Table 1). These antibodies were isolated from sera by immunoadsorption, using a thick suspension of S45/20 and then dissociated with glycine-CHl buffer 0.1M pH 3. These antibodies showed little agglutinating capacity for S45/20; however non-agglutinating antibodies were bound to the bacteria up to 1.5 micrograms g as demonstrated by Coombs test. Apart from the incomplete antibodies against external antigens of smooth Brucella abortus strains detected in long-term stimulated cattle, non-agglutinating antibodies with specificity for deeper antigens of the smooth bacteria were evidenced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1997

[A case of red blood cell(RBC) agglutination on peripheral blood smear and effect of cefpirom sulfate].

We observed red blood cell (RBC) agglutination on peripheral blood smear and an abnormal RBC distribution histogram that suggested the influence of cefpirom sulfate. The patient was receiving cefpirom sulfate when RBC agglutination and the abnormal pattern were recognized, but these abnormalities disappeared as soon as the drug was withdrawn. When the peripheral blood sample was re-examined after warming for an hour at 37 degrees C, the abnormal pattern almost disappeared and RBC agglutination became minimal. We also observed cold agglutination reaction by using O type washed RBCs from a healthy individual that were reacted with cefpirom sulfate, but found only minimal agglutination at RT. As the drug concentration and plasma concentration were increased, we observed more agglutination at 4 degrees C, but this agglutination disappeared after incubation for an hour at 37 degrees C. The cold agglutinin titer was normal. We thus believe that the cause of RBC agglutination in this case was caused by cefpirom sulfate.

Cells, Cultured↗
PubMed1978

Surface modification of guinea pig sperm during in vitro capacitation: an assessment using lectin-induced agglutination of living sperm.

Plant lectins have been used to advantage to study carbohydrate-containing cell surface receptors in numerous systems. In this study, a simple, reliable assay was developed to quantitate lectin-induced agglutinability of sperm. This assay was used successfully to compare some of the surface properties of uncapacitated and capacitated guinea pig sperm. Capacitation was induced by incubating sperm in minimum capacitation medium (MCM) or modified Tyrodes solution (T-PL). Control incubations were done in Ham's F-10 or Hank's balanced salt solution which do not support capacitation. At timed intervals during incubation, sperm samples were assessed for pattern and degree of lectin-induced agglutination. Results establish that: (1) soybean agglutinin (SBA) and to a lesser extent concanavalin A (Con A) induced agglutinability of guinea pig sperm increase during in vitro capacitation in MCM; (2) a similar increase in SBA induced agglutinability occurs during capacitation in T-PL, but not in the non-capacitating media; and (3) for sperm incubated in MCM or T-PL, there is a significant increase in tail to tail agglutination after capacitation. The results with SBA demonstrate that D-galactose and/or N-acetyl-D-galactosamine containing receptor sites or the guinea pig sperm surface are affected by capacitation, and this effect occurs, at least in part, in the sperm tail. Possible explanations for the observed increase in agglutinability are discussed. The agglutination assay may prove useful as a direct test for the occurrence of capacitation and may be especially valuable for species having a small acrosome or limited number of eggs.

Acrosome↗
PubMed1975

Cell cycle dependent agglutinability, distribution of concanavalin A binding sites and surface morphology of normal and transformed fibroblasts.

In studies on phenotypic reversion of transformed cells to normal growth patterns, we investigated the effect of dibutyryl cyclic AMP (dbc-AMP) and a protease inhibitor (TLCK) on growth of SV40-transformed mouse fibroblasts (3T3). The results did not support the hypothesis that transformed cells grown with dbc-AMP or TLCK are induced to contact-mediated growth control. The growth rate of SV-3T3 cells grown with the drugs was strongly reduced, due to accumulation of the cells in the G2 phase of the cell cycle. In addition, decreased agglutinability with concanavalin A (Con A) of those SV-3T3 cells was not caused by a direct effect of the drugs on the cell surface, but by partial synchronization of the cells in the G2 phase of the cycle. In synchronized cultures agglutinability of transformed cells reached a minimum in G2 and was maximal in mitosis and G1. Normal cells agglutinated only in mitosis. This suggested that agglutinability of cells is somehow cell cycle dependent. Cytochemical investigations on normal and transformed 3T3 cells had shown that Con A-induced redistribution of binding sites on the surface of these cells is not correlated with agglutinability. The present work on replicas confirmed this, but indicated also that normal 3T3 cells have more extended lamellipodia with less Con A binding sites than SV-3T3 cells. Preliminary scanning electron microscope data showed cell cycle dependent changes in 3T3 cells and also showed that confluent 3T3 and SV-3T3 cells suspended for agglutination tests had a different surface morphology. These results may represent additional factors important for differences in cell agglutinability by Con A.

Agglutination↗
PubMed1975

Loss of agglutinating specificity in stock cultures of Rhizobium meliloti.

Several strains of Rhizobium meliloti which have been subcultured for 23-33 years have changed from being markedly specific in their somatic agglutination reactions to become widely cross-reactive. On the other hand a fresh collection of the same species obtained from naturally nodulated, field-grown plants revealed the high degree of agglutinating specificity which had previously characterised the old cultures. Attempts to reselect a specific substrain from old cross-agglutinating cultures by six plant passages, or to detect change to cross reactivity by ten successive subcultures of recent isolates were unsuccessful. However, one strain, isolated in 1939, was recently found to contain both specific and cross-reactive substrains. Practically all the cultures, both old and recent, showed considerable mutability in colony characteristics but none of these was consistently correlated with cross agglutinability. Instability in 6.4% (w/v) NaCl was characteristic of the cross-agglutinating cultures. Cross reactivity was associated with a shared lipopolysaccharide antigen (LPS) which appeared to be obscured by an outer antigen in most strains still showing specific agglutinability. In the exceptional case of strain SU27, agglutination could be attributed to its specific LPS.

Agglutination↗