Zbl. Bakt. 274, 446-455 (1991) © Gustav Fischer Verlag, StuttgartlNew York

A Murine Monoclonal Antibody that Recognizes a Genus-Specific Epitope in the Salmonella Lipopolysaccharide Outer Core RAYMOND S. W. TSANG!, KLAUS NIELSEN 2 , M. DIANE HENNING 2 , SIEGFRIED SCHLECHT 3 , and STOJANKA ALEKSIC 4 1 2



Department of Microbiology, University of Hong Kong, Hong Kong Animal Diseases Research Institute, Agriculture Canada, Station H, Nepean, Ontario, Canada Max-Planck-Institut fur Immunbiologie, D-7800 Freiburg-Zahringen Medizinaluntersuchungsanstalt, Institute of Hygiene, D-2000 Hamburg

With 1 Figure· Received April 6, 1990 . Accepted in revised form August 1, 1990


A murine monoclonal antibody 105 made from spleen cells of a mouse immunized with a mixture of common Salmonella serotypes reacted specifically with salmonellae from the most frequently encountered 0 serogroups of A (0: 2) to E (0: 3), and with strains from the less common 0 serogroups that represent the subspecies I, II, III b , IV, V and VI. Specificity for Salmonella was demonstrated by the lack of reactivity of monoclonal antibody 105 with any of the 30 other different species of Gram-positive and Gram-negative bacteria tested including 16 species in the family of Enterobacteriacae. Studies to elucidate its binding epitope have shown that it reacts with the three distal sugar residues joined through specific anomeric linkages as present only in the Salmonella lipopolysaccharide outer core, which explains its specificity for the Salmonella. The failure of monoclonal antibody 105 to react with a subspecies IlIa Salmonella suggested a different outer core structure in this strain of Salmonella and also that monoclonal antibodies to the outer core of Salmonella lipopolysaccharide should be useful in the molecular analysis of their diversity. Zusammenfassung Ein muriner monoklonaler Antikorper 105 aus den Milzzellen einer Maus, die mit einer Mischung gangiger Salmonella-Serotypen immunisiert worden war, reagierte spezifisch mit Salmonellen cler am haufigsten auftretenden O-Serogruppen A (0: 2) bis E (0: 3) sowie mit Stammen der weniger haufigen O-Serogruppen, die die Subspezies I, II, III b, VI, V und VI reprasentieren. Die Salmonella-Spezifitat wurde durch das Fehlen einer Reaktion des monoklonalen Antikorpers 105 mit 30 anderen gepruften Spezies gram-positiver und gramnegativer Bakterien, einschlielSlich der 16 Spezies in der Familie Enterobacteriaceae nach-

Salmonella Specific Monoclonal Antibody


gewiesen. Untersuchungen zur Klarung des Bindungs-Epitops zeigten, da~ er mit den drei distalen Zuckerresten reagiert, die durch spezifische anomere Bindungen verkniipft sind, wie sie nur im au~eren Kern des Salmonella-Lipopolysaccharids vorkommen. Dies erklart die Salmonella-Spezifitat. Das Nichtreagieren des monoklonalen Antikorpers 105 mit der Salmonella-Subspezies III. deutet auf eine andere Struktur des au~eren Kerns bei diesem Salmonellenstamm hin. Monoklonale Antikorper gegen den au~eren Kern des SalmonellenLipopolysaccharids sind somit auch zum Erkennen von Strukturunterschieden von Nutzen.

Introduction Salmonellae are a very diverse group of bacteria (over 2000 serotypes have been identified) which are primarily intestinal parasites of vertebrates. The most common disease they cause in man is gastroenteritis (often called "food poisoning"). For the control of salmonellosis, detection of salmonellae plays a central role. The current method of detecting salmonellae in food or other specimens involves the isolation and identification of the organisms by elaborate biochemical and serological methods (6, 13). Such procedures are not only time-consuming and labour-intensive but are also costly. An alternative is to apply immunological methods to detect these organisms either directly in the food or after brief enrichment culture in selective media (19,22). This approach would not only circumvent the costly and labour-intensive procedures in isolation and identification of the bacteria, the immunological method has the additional advantage of speed. However, success in any immunological approach depends on the availability of specific antiserum. Traditional methods of raising antisera against Salmonella consist of immunization of experimental animals with Salmonella whole cells (15). With the current knowledge that points to the numerous common antigens among the Enterobacteriaceae (1), such polyclonal hyperimmune antisera against Salmonella naturally contain many cross-reacting antibodies. Although absorption of the hyperimmune antisera with related bacteria has been used to improve the specificity of such polyclonal antisera, their quality is both difficult to control and to ensure in different batches of the preparations. Another deterrent to this immunological approach is the lack of a suitable antiserum against a common Salmonella genus-specific antigen which can be applied to the immunological detection of the many serotypes of salmonellae involved in food poisoning. Lipopolysaq:haride (LPS) is one of the major surface antigens of Salmonella. It is responsible for both the sero-specificity and the endotoxicity of the Salmonella cell. Details of the chemical structure of the Salmonella LPS including both the smooth (bearing the repeating O-specific side chains) and the rough antigens (bearing only the core oligosaccharide without the O-polysaccharide side chains) have been well studied and published (18, 28). Serological identification of salmonellae depends on the detection of specific 0 antigens (found on the repeating units of O-specific side chains of the LPS molecule) and H antigens (flagellar protein antigens) (6). In contrast to the diversity of their O-polysaccharide structures (hence their 0 antigen specificities), salmonellae are said to have ;l common LPS outer core structure (27) which is therefore a potential candidate as a genus-specific antigen for the immunological assay of this very diverse group of organisms. It is with this understanding that hybridoma monoclonal antibodies (MAbs) to the Salmonella LPS outer core structure were sought. In this communication, we describe the production, characterization and application of such a murine MAb specific for Salmonella.


R. S. W. Tsang, K. Nielsen, M. D. Henning, S. Schlecht, and S. Aleksic

Materials and Methods Bacterial strains, culture conditions, and antigens. Salmonella minnesota isogenic enterobacterial common antigen mutants, Salmonella Ra to Re mutants, and the Escherichia coli and Shigella rough mutants that have the Rl to R4 and K-12 core types were obtained from the strain collection of Max-Planck-Institut fur Immunbiologie, Freiburg, Federal Republic of Germany. Subspecies II to VI Salmonella were obtained from Salmonella-Zentrale, Hygienisches Institut, Hamburg, Federal Republic of Germany. Salmonella for the immunization of mice to produce hybridoma monoclonal antibodies were either avian isolates (S. typhimurium, S. hadar and S. enteriditis) or had been purchased as killed suspensions from Difco Laboratories (Detroit, Michigan, USA) (S. typhi and S. paratyphi A). Some avian isolates were used for immunization of mice since it has been one of the aims of the present research to develop MAbs against all the commonly encountered salmonellae from chickens for the control of salmonellosis in the poultry-industry. All other bacteria used were clinical isolates obtained from the clinical microbiology laboratory of the University of Hong Kong, and they were identified by standard biochemical and serological methods (16). Bacteria used for the whole-cell radioimmunoassay (RIA) were grown as static cultures in brain heart infusion broth (Oxoid Ltd., London, England) for 16 to 18 h at 37°C. Cells were then inactivated with 0.5% formalin before being harvested by centrifugation at 5000 x g for 15 min. Harvested bacteria were washed twice with large volumes of sterile phosphatebuffered saline (PBS), and stored at 4°C. Bacteria for immunization of mice and for colony dot-blot RIA were grown on blood or nutrient agar plates. LPS from smooth strains were extracted by the hot phenol-water method of Westphal and Jann (26) while those from rough mutants were extracted by the phenol-chloroformpetroleum ether method of Galanos et al. (7). Both smooth and rough LPS were purified by repeated ultracentrifugation at 105000 x g. Production of hybridoma monoclonal antibodies. Balb/c mice were immunized three times weekly for four weeks intraperitoneally with 106 of each of the heat-killed cell suspensions of S. typhimurium, S. paratyphi A, S. typhi, S. hadar and S. enteritidis. Hybrids were formed by fusing immune spleens cells with the mouse plasmacytoma cells of the SP/2 cell line (14). Hybrids that produced antibodies to the S. typhimurium LPS were cloned twice and injected into Balb/c mice for ascites fluid production. Isotype determination of the monoclonal antibodies was done by agar gel diffusion using isotype-specific afltisera obtained from Meloy Labs (Springfield, Virginia, USA). Serological methods. Screening of hybrids that produce specific antibodies was done by an enzyme-linked-immunosorbent-assay (ELISA) (5, 25). Antibody binding was assessed by addition of 1 mM hydrogen peroxide and 4 mM 2,2'-Azino-bis(3-ethylbenzthiazoline-6sulfonic acid) (ABTS) (both from Sigma Chern. Co., St. Louis, Missouri, USA) as substrates and the plate was shaken continously for 10 min before colour development was measured by a spectrophotometer. Whole-cell RIA and dot-blot RIA were done by previously described methods (23,24). Colony dot-blot RIA was essentially done as described by Heckels and Virji (11) except that a much heavier cell suspension was used in applying the bacteria to the nitrocellulose paper (0.45 ftm pore diameter; Schleicher and Schuell, Dassel, Federal Republic of Germany).


1. Selection, preliminary characterization and specificity of MAb 105 One of the hybridomas obtained from a fusion using immune spleen cells of a mouse immunized with a mixture of Salmonella serotypes (described in Materials and Methods) produced MAbs that reacted with Salmonella LPS from different 0 serogroups, and hence it was chosen for further studies. This MAb designated 105 was of

Salmonella Specific Monoclonal Antibody


the isotype IgG2a, and it could be shown to bind staphylococcal protein A by dot blot immunoassay using 125I-Iabelled protein A. Besides reacting with the most commonly encountered serogroups A (0: 2) to E (0: 3) Salmonella that belonged to subspecies I, strains that represented the other subspecies (II to VI) or belonged to the higher 0 serogroups (G [0: 13], H [0: 6, 14], V [0: 44], Y [0: 48], and 66) were also reactive with MAb 105 (Fig. 1). The only exception was a strain belonging to the monophasic Arizona group of subspecies lIla. In contrast, all the other common members of the family Enterobacteriaceae tested by colony dot-blot RIA were negative and these included one strain each of Escherichia coli, Klebsiella pneumoniae, K. oxytoca, Enterobacter aerogenes, E. cloacae, Shigella sonnei, S. {lexneri, Proteus mirabilis, P. vulgaris, Providencia stuart;;, Morganella morganii, Edwardsiella tarda, Citrobacter freundii, C. diversus, Serratia marcescens, and Yersinia enterocolitica. Other common clinical isolates that did not react with the MAb 105 included Pasteurella multocida, Haemophilus in{luenzae, Acinetobacter antitratus, A. lwoffii, Alcaligenes faecalis, Pseudomonas aeruginosa, P. putida, P. cepacia, Aeromonas hydrophila, Vibrio parahaemolyticus, Plesiomonas shigelloides, Staphylococcus epidermidis, Streptococcus faecalis, Bacillus species, Moraxella species, and Flavobacterium species. 2. Epitope determination for MAb 105 To characterize the epitope specificity of this antibody, purified LPS from different rough mutants of Salmonella (Ra to Re) and the related enterobacteria (E. coli and Shigella, R1 to R4 and K-12 types) (17,18,21) were tested for reactivity with the MAb 105 by the dot-blot RIA (Table 1). From this table, it is apparent that MAb 105 reacted with LPS from the Salmonella Ra, RbI> and Rb 2 mutants, but not from the Rb 3 , Rc, Rd b Rd 2, and Re mutants. The reactivities with the Ra, Rb b and Rb 2 mutants LPS also showed decreasing binding of the MAb as the LPS structure became smaller in terms of the number of sugar residues present. Therefore it seemed the best fit for MAb 105 was the complete Ra LPS structure and the minimum structure for MAb 105 binding (under the present testing condition) was the Rb 2 LPS with a galactose linked a 1, 3 to the basal glucose in the core LPS; or the binding site of MAb 105 must extend over at least the three sugar residues of: N-acetylglucosamine ~ glucose a



The results as shown in Table 1 have been largely confirmed by testing these Salmonella and their related enterobacterial rough mutants using two other independent methods: boiled whole cell RIA (Table 2) and colony dot-blot RIA with the live whole cells. The only exceptional finding was the reactivity of whole cells of S. {lexneri 4b(F4130), which has the R3 core type, with the MAb 105 in both the boiled whole cell RIA (Table 2) and the colony dot-blot RIA (data not shown). Also evident from Table 2 was the ability of MAb 105 to react with smooth whole cells of S. minnesota irrespective of the presence or absence of enterobacterial common antigen. 3. Epitope mapping of the outer core structures of Salmonella LPS using two different MAbs with defined reactive antigenic sites Two hybridoma MAbs, 105 which reacted with the Salmonella Rb 2 incomplete core LPS, and T6 which reacted with the Salmonella Ra complete core LPS, were used to probe the antigenic sites on the LPS of different Salmonella subspecies and serogroups (Fig. 1). While all five subspecies I Salmonella from the most commonly encountered


R. S. W. Tsang, K. Nielsen, M. D. Henning, S. Schlecht, and S. Aleksic

Table 1. Dot-blot RIA (23) to determine the reactivity of monoclonal antibody 105 with PCP-extracted and purified LPS from Salmonella and related enterobacterial rough mutants




Bacterial strain

Strain No"

Core type

PIC Ratios b

S. typhimurium his 386 S. typhimurium SL1780 S. minnesota R345 S. typhimurium TV148 S. typhimurium S. minnesota R7 S. minnesota R4 S. minnesota R595 E. coli 08-:K27Shigella boydii type 3E. coli 08-:K27E. coli 08-:K42E. coli OlOO-:K Shigella flexneri 4bE. coli 0111-:K58E.coli 014:K7E. coli 014:K7 E. coli K-12 E.coli K-12 No antigen control (Without LPS)

SF1591 SFI0212 SF1127 SF1561 SL848 c SF1121 SF1118 SF1167 F1283 F3140 F470 F576 F632 F4130 F653 F2513 F1327 W3100 D21

Ra RbI Rb2 Rb 3 Rc Rd l Rd2 Re Rl Rl Rl

51 29 10 1.1 1.2 0.9 1.2 1.1 0.9 1.1 1.2 1.1 1.1 1.8


R2 R3 R3 R4 R4 K-12 K-12


1.0 1.0 1.0 1.0 1.0

From the strain collection of Max-Planck-Institut fiir Immunbiologie, characteristics described in (8, 17). PIC = (Positive divided by Control; positive counts per minute bound in the presence of monoclonal antibodies divided by control counts per minute bound in the absence of monoclonal antibodies in the radioimmunoassay). S. typhimurium SL848 is a mutant deficient in UDP-galactose-4-epimerase; LPS was extracted from cells grown in mineral-salts medium without galactose using the phenolchloroform-petroleum ether method and hence Rc LPS was obtained.

serogroups A (0: 2), B (0: 4), C (0: 6, 7, 8), D (0: 9) and E (0: 3) were reactive with both MAbs 105 and T6, one subspecies IV strain, S. IV 44: Z4,Z24:- was found to react with MAb 105 only but not with MAb T6, and one subspecies lIla strain, S. IlIa 1, 13, 23: Z4,Z24:- did not react with both MAbs T6 and 105. Discussion In this report, we have described a murine monoclonal anti-Salmonella outer core LPS antiboely 105 specific for Salmonella. We believe that MAbs specific for the outer core structure of Salmonella lipopolysaccharide are useful for the detection and identification of salmonellae in clinical, food and other specimens. Besides being able to detect a number of serotypes and serogroups of salmonellae using a single reagent, other positive attributes for targeting the LPS core antigens in detection/identification systems include: (i) in most wild isolates of smooth bacteria, there is always a propor-


Salmonella Specific Monoclonal Antibody

Table 2. Boiled whole cell RIA (23) to determine the reactivity of monoclonal antibody 105 with isogenic Salmonella ECA mutants and rough mutants from E. coli and Shigella spp. Bacteria

Strain No."



PIC Ratio b

S. typhimurium his 386 E. coli 08-:K27E. coli 08-:K27Shigella boydii type 3E. coli 08-:K42E. coli 0100-:K E. coli 0111-:K58Shigella flexneri 4bE. coli 014:K7E.coli 014:K7 E.coli K-12 E.coli K-12

SF1591 F470

Ra Rl Rl Rl

ECN-negative ECA-immunogenic ECA-negative ECA-immunogenic

R2 R2 R3 R3 R4 R4

ECA-immunogenic ECA-negative

231 2.3 6.8 1.8 2.7 1.8 6.2 129 2.8

S. minnesota S. minnesota


F3140 F576 F632


F4130 F2513 F1327

021 W3100

SFl0158 SFl0159

K-12 K-12 Ra Ra

ECA-negative ECA-positive

5.7 4.7

3.2 317


• As in Table 1. b PIC ratios as defined in Table 1. CECA = Enterobacterial Common Antigen.

tion of their core LPS not being substituted with O-specific side chains and therefore exposed on the cell surface (10,20); (ii) the fact that LPS is a major surface antigen and is easily released during growth (4, 12) makes them possibly suitable as targets for detection. To be useful as a serological reagent to detect and identify salmonellae, it not only has to be specific in not reacting with other bacteria, but it also has to react with all the commonly encountered salmonellae. While Salmonella serotypes of the most frequently encountered serogroups of A (0: 2) to E (0: 3) were MAb IDS-reactive, strains belonging to the higher 0 serogroups, e.g. G (0: 13), H (0: 6, 14), V (0: 44), Y (0: 48) and 66 were also positive. Strains that are usually isolated from coldblooded animals and the environment (subspecies II to VI) were also positive with the exception of a strain belonging to the monophasic Arizona group of subspecies III. (Fig. 1). Therefore, MAb 105 is a potentially useful polyvalent Salmonella genusspecific serological reagent. The ability of MAb 105 to react with smooth whole cells of Salmonella (Table 2) is also a positive attribute for developing this MAb as a polyvalent serological reagent for the identification and detection of salmonellae since most wild isolates exist as smooth forms. The specificity of the MAb 105 has been demonstrated by its lack of reactivity with 30 different species of Gram-positive and Gram-negative non-Salmonella bacteria including 16 species in the family of Enterobacteriaceae where cross-reactions with Salmonella is most likely. The nature of its reacting epitope also makes MAb 105 likely to be specific for Salmonella since this antibody recognizes at least three sugar residues in a particular anomeric linkage found only in the typical Salmonella Ra core. Therefore a cross-reacting non-Salmonella strain must either have all these three sugars in the same sequence and linkages as in the Salmonella or it has to be deficient in its core oligosaccharide as in the case of the RbI or Rb 2 Salmonella rough mutant.


R. S. W. Tsang, K. Nielsen, M. D. Henning, S. Schlecht, and S. Aleksic

The specificity of the present MAb 105 suggests a spectrum of reactivity similar to the polyvalent Salmonella Felix 01 bacteriophage (3). However, no attempt has been made to correlate the reactivity of different Salmonella types with the MAb and their sensitivity to the Felix 01 phage. Both reagents have the potential for broad detection or identification of Salmonella strains but neither will provide the serogroup or serotype identification that is necessary for epidemiological investigation. Resistance of salmonellae strains to the Felix 01 phage (2) as well as the lack of reactivity of some Salmonella strains with the anti-LPS core MAbs (present data) have both led to the suggestion of a different LPS-core structure in some Salmonella strains. Fig.l. Colony dot-blot RIA ~o show the reactivities of MAbs 105 and T6 with different serogroups and subspecies of Salmonella.

Al * A2 A3 A4

AS A6 A7 B1 B2 B3 B4 B5 B6 B7



s. paratyphi A S. typhimurium S. block ley S.newport S. typhi S.anatum S. II ngozi S. IlIa arizonae S. Ilh arizonae S. IV S. V maregrosso S. VI ferlac Escherichia coli No antigen control

A (0:2) B (0:4) C2 (0:6,8) C2 (0:6,8) D (0:9) E (0:3) Y (0:48) G (0:13) G(O:13) V (0:44) 66 H (0:6,14)

SubAntigenic formula species I







1,2,12: a:1, 4, 12: i: 1, 2 6,8: k: 1,5 6, 8: e, h: 1, 2 9, 12, Vi: d: 3, 10: e, h: 1, 6 48: ZlO: 1,5 1, 13, 23: Z4, Z24: 13, 22: 1, v: 1,5, 7 44: Z4, Z24: 66: Z3S:1,6, 14,25: a: e, n, x

Strain Number LNI74280 LN34166 LN184144 LN180639 LN66963 LN165075 H3096/87 CDC3878-58 IP3978/83 H2798/87 H186/76 IP386/60

* Designation of strains as shown in the Figure. Strains Al to A6 and B6 were clinical

isolates obtained from blood or stool specimens in Hong Kong; strains A7, and Bl to B5 were from the strain collection of Hygienisches Institut in Hamburg, West Germany.

Salmonella Specific Monoclonal Antibody


Although S. flexneri 4b-(F4130), which has the R3 core type, reacted with the MAb 105 in both the boiled whole RIA (Table 2) and the colony dot-blot RIA (data not shown), purified LPS from this strain did not react. This suggested that the MAb 105 epitope in the S. flexneri strain F4130 was expressed on either the capsule or other carbohydrate residues of the cell envelope. Further testing by colony dot-blot RIA of two other Shigella isolates (S. sonnei and S. flexneri) from patients with diarrhea in Hong Kong did not show reactivity with the MAb 105. Therefore, to obtain definitive data on the nature of the reactive antigen in this particular strain of Shigella, further experiments to delineate its locality in the bacterial cell are needed. Whether it would involve glycoproteins of the bacterial cell wall as was suggested (9) in one report on a similar finding of a carbohydrate epitope present on whole cells but not on extracted LPS molecules, is most intriguing since it is generally believed that bacteria do not have glycoproteins. Another interesting finding was that the MAb lOS-negative monophasic Arizona strain also did not react with another MAb T6 which is specific for the terminal disaccharide of the Salmonella outer core LPS structure (23). This indicates that this subspecies IlIa Arizona strain has an LPS outer core structure different from that of the typical Salmonella Ra core. The finding of a subspecies IV strain, S. IV 44 : Z4, Z24:-, that reacts with MAb 105 but not with MAb T6 indicates yet another LPS outer core type in this particular strain of subspecies IV Salmonella. Indeed, differences in the LPS outer core structures have recently been demonstrated by us in S. adelaide (24a) and other serotypes of Salmonella (manuscript under preparation). Therefore, besides being a potentially very useful polyvalent serological reagent for the detection of different serotypes of salmonellae, the present MAb together with other MAbs against different epitopes on the Salmonella LPS outer core structure are excellent reagents for the mapping of structural differences in the LPS core structures in different serotypes of salmonellae. The present study has indeed confirmed and extended our earlier finding concerning an atypical outer core structure in the S. adelaide LPS which was different from that of S. typhimurium and S. minnesota (24a). We are now applying this approach to study different serotypes of salmonellae representing all the 46 0 serogroups and 7 subspecies with the aim to define the core structures in this very diverse group of medically important bacteria. Eventually we hope some of these Salmonella core LPS specific MAbs will be applicable in the routine laboratory diagnosis of these bacteria.

Acknowledgments. The work of one of the authors R. S. W. Tsang, has been supported by a Strategic Research Grant from the University of Hong Kong, and in part by a grant from the Royal Hong Kong Jockey Club. References 1. Barber, C. and E. Eylan: The numerous common antigens of Enterobacteriaceae. Zbl. Bakt. Hyg., I. Abt. Orig. A 244 (1979) 251-259 2. Bockemiihl, J.: Die Lysosensibilitat von Stammen der Salmonella Subgenera I-IV gegeniiber dem Phagen 0-1. Ihre mogliche Bedeutung fiir die Klassifikation des Genus Salmonella. Med. Microbiol. Immunol. 158 (1972) 44-53 3. Cherry, W. B., B. R. Davis, P. R. Edwards, and R. B. Hogan: A simple procedure for the identification of the genus Salmonella by means of a specific bacteriophage. J. Lab. Clin. Med. 44 (1954) 51-55 31 Zhl. Bakt. 274/4


R. S. W. Tsang, K. Nielsen, M. D. Henning, S. Schlecht, and S. Aleksic

4. De Voe, I. W. and]. E. Gilchrist: Release of endotoxin in the form of cell wall blebs during in vitro growth of Neisseria meningitidis. J. Exp. Med. 138 (1973) 1156-1167 5. Engvall, E. and P. Perlman: Enzyme-linked immunosorbent assay. ELISA. III. Quantitation of specific antibodies by enzyme labelled anti-immunoglobulin in antigen coated tubes. J. Immunol. 109 (1972) 129-135 6. Ewing, W. H.: Identification of Enterobacteriaceae, 4th ed. Elsevier Science Publ. Co., New York (1986) 7. Galanos, c., O. Liideritz, and O. Westphal: A new method for the extraction of Rlipopolysaccharides. Eur. J. Biochem. 9 (1969) 245-249 8. Galanos, c., O. Liideritz, and O. Westphal: Newer aspects of the chemistry and biology of bacterial lipopolysaccharides, with special reference to their lipid A component. In: The biochemistry of lipids II, vol. 14 (T. W. Goodwin, ed.), pp. 239-334. University Park Press, Baltimore (1977) 9. Galili, U., R. E. Mandrell, R. N. Hamadeh, S. B. Shohet, and]. M. Griffiss: Interaction between human natural anti-a-galactosyl immunoglobulin G and bacteria of the human flora. Infect. Immun. 56 (1988) 1730-1737 10. Goldman, R. C. and L. Leive: Heterogeneity of antigenic-side chain length in lipopolysaccharide from Escherichia coli 0111 and Salmonella typhimurium LT2. Eur. J. Biochem. 107 (1980) 245-249 11. Heckels, ]. E. and M. Virji: Monoclonal antibodies against gonococcal pili: uses in the analysis of gonococcal immunochemistry and virulence. In: Monoclonal antibodies against bacteria, vol. I, (A. ]. L. Macario and E. C. de Macario, eds.), pp. 1-35. Academic Press, Inc., New York (1985) 12. Hoekstra, D., ]. W. Van der Laan, L. D. Leij, and B. Witholtl: Release of outer membrane fragments from normally growing Escherichia coli. Biochem. Biophys. Acta 455 (1976) 8889-8899 13. Kelly, M. T., D. ]. Brenner, and]. ]. Farmer III: Enterobacteriaceae. In: Manual of Clinical Microbiology, 4th ed. (E. H. Lennette, A. Balows, W.]. Hausler jr., and H.J. Shadomy, eds.), pp. 263-277. American Society for Microbiology, Washington/DC (1985) 14. Kennet, R. H., K. A. Denis, A. S. Tung, and N. R. Klinman: Hybrid plasmacytoma production: fusions with adult spleen cells, monoclonal spleen fragments, neonatal spleen cells and human spleen cells. Curr. Top. Microbiol. Immunol. 81 (1978) 77-91 15. Le Minor, L. and R. Rohde: Guidelines for preparation of Salmonella antisera. WHO Collaborating Centre for Reference and Research on Salmonella, Institut Pasteur, Paris (1986) 16. Lennette, E. H., A. Balows, W.]. Hausler jr., and H.]. Shadomy: Manual of Clinical Microbiology, 4th ed. American Society for Microbiology, WashingtonlDC (1985) 17. Liideritz, 0., M. A. Freudenberg, C. Galanos, V. Lehmann, E. T. Rietschel, and D. H. Shaw: Lipopolysaccharides of gram-negative bacteria. Curr. Top. Membr. Trans. 17 (1982) 79-151 18. Liideritz, 0., O. Westphal, A. M. Staub, and H. Nikaido: Isolation and chemical and immunological characterization of bacteriallipopolysaccharides. In: Microbial Toxins (G. Weinbaum, S. Kadis, and S. ]. Ajl, eds.), pp. 145-233. Academic Press, Inc., New York (1971) 19. Mohr, H. K., H. L. Trenk, and M. Yeterian: Comparison of fluorescent-antibody methods and enrichment serology for the detection of Salmonella. Appl. Microbiol. 27 (1974) 324-328 20. Paiva, E. T. and P. H. Makela: Lipopolysaccharide heterogeneity in Salmonella typhimurium analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Eur. J. Biochem. 107 (1980) 137-143 21. Rietschel, E. Th. and O. Liideritz: Struktur von Lipopolysaccharid und Taxonomie Gram-negativer Bakterien. Forum Mikrobiol. 1 (1980) 12-20

Salmonella Specific Monoclonal Antibody


22. Sperber, W. H. and R. H. Deibel: Accelerated procedure for Salmonella detection in dried foods and feeds involving only broth cultures and serological reactions. Appl. Microbiol. 17 (1969) 533-539 23. Tsang, R. S. W., K. H. Chan, P. Y. Chau, K. C. Wan, M. H. Ng, and S. Schlecht: A murine monoclonal antibody specific for the outer core oligosaccharide of Salmonella lipopolysaccharide. Infect. Immun. 55 (1987) 211-216 24. Tsang, R. S. W. and P. Y. Chau: Production of Vi monoclonal antibodies and their application as diagnostic reagents. J. Clin. Microbiol. 25 (1987) 531-535 24a. Tsang, R. S. W. and S. Schlecht: Smooth lipopolysaccharide of Salmonella adelaide has an atypival Salmonella Ra core. Res. Microbiol. 141 (1990) 671-678 25. Voller, A., D. Bidwell, and A. Bartlett: Enzyme-linked immunosorbent assay. In: Manual of clinical immunology, 2nd ed. (N. R. Rose and H. Friedman, eds.), pp. 359-371. American Society for Microbiology, WashingtonfDC (1980) 26. Westphal, O. and K. Jann: Extraction with phenol-water and further application of the procedure. Meth. Carbohydr. Chern. 5 (1965) 83-90 27. Westphal, 0., K. Jann, and K. Himmelspach: Chemistry and immunochemistry of bacteria lipopolysaccharides as cell wall antigens and endotoxins. Progr. Allergy 33 (1983) 9-39 28. Wilkinson, S. G.: Composition and structure of bacteriallipopolysaccharides. In: Surface carbonhydrates of the prokaryotic cell (1. W. Sutherland, ed.), pp. 97-175. Academic Press, Inc., New York (1977)

Dr. Raymond S. W. Tsang, Department of Microbiology, University of Hong Kong, Pathology Building, Queen Mary Hospital Compound, Pokfulam Road, Hong Kong

A murine monoclonal antibody that recognizes a genus-specific epitope in the Salmonella lipopolysaccharide outer core.

A murine monoclonal antibody 105 made from spleen cells of a mouse immunized with a mixture of common Salmonella serotypes reacted specifically with s...
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