scholarly journals Characterization and Formulation of Multiple Epitope-Specific Neutralizing Monoclonal Antibodies for Passive Immunization against Cryptosporidiosis

2000 ◽  
Vol 68 (5) ◽  
pp. 2608-2616 ◽  
Author(s):  
Deborah A. Schaefer ◽  
Beth A. Auerbach-Dixon ◽  
Michael W. Riggs
Keyword(s):  
Monoclonal Antibodies ◽  
Cryptosporidium Parvum ◽  
Polyclonal Antibodies ◽  
Passive Immunization ◽  
Infection Process ◽  
Enzyme Linked Immunosorbent Assay ◽  
Intestinal Infection ◽  
Coccidian Parasite ◽  
Epitope Specificity ◽  
Significant Efficacy

ABSTRACT The coccidian parasite Cryptosporidium parvum causes diarrhea in humans, calves, and other mammals. Neither immunization nor parasite-specific pharmaceuticals that are consistently effective against this organism are available. While polyclonal antibodies against whole C. parvum reduce infection, their efficacy and predictability are suboptimal. We hypothesized that passive immunization against cryptosporidiosis could be improved by using neutralizing monoclonal antibodies (MAbs) targeting functionally defined antigens on the infective stages. We previously reported that the apical complex and surface-exposed zoite antigens CSL, GP25-200, and P23 are critical in the infection process and are therefore rational targets. In the present study, a panel of 126 MAbs generated against affinity-purified CSL, GP25-200, and P23 was characterized to identify the most efficacious neutralizing MAb formulation targeting each antigen. To identify neutralizing MAbs, sporozoite infectivity following exposure to individual MAbs was assessed by enzyme-linked immunosorbent assay. Of 126 MAbs evaluated, 47 had neutralizing activity. These were then evaluated individually in oocyst-challenged neonatal mice, and 14 MAbs having highly significant efficacy were identified for further testing in formulations. Epitope specificity assays were performed to determine if candidate MAbs recognized the same or different epitopes. Formulations of two or three neutralizing MAbs, each recognizing distinct epitopes, were then evaluated. A formulation of MAbs 3E2 (anti-CSL [αCSL]), 3H2 (αGP25-200), and 1E10 (αP23) provided highly significant additive efficacy over that of either individual MAbs or combinations of two MAbs and reduced intestinal infection by 86 to 93%. These findings indicate that polyvalent neutralizing MAb formulations targeting epitopes on defined antigens may provide optimal passive immunization against cryptosporidiosis.

scholarly journals Efficacy of Monoclonal Antibodies against Defined Antigens for Passive Immunotherapy of Chronic Gastrointestinal Cryptosporidiosis

2002 ◽  
Vol 46 (2) ◽  
pp. 275-282 ◽  
Author(s):  
Michael W. Riggs ◽  
Deborah A. Schaefer ◽  
Sushila J. Kapil ◽  
Lise Barley-Maloney ◽  
Lance E. Perryman
Keyword(s):  
Monoclonal Antibodies ◽  
Cryptosporidium Parvum ◽  
Surface Antigens ◽  
Intestinal Infection ◽  
Passive Immunotherapy ◽  
Prophylactic Efficacy ◽  
Significant Efficacy ◽  
The Individual ◽  
Immunocompromised Hosts ◽  
Persistently Infect

ABSTRACT Cryptosporidium parvum is an important cause of diarrhea in humans and calves and can persistently infect immunocompromised hosts. Presently, there are no consistently effective parasite-specific drugs for cryptosporidiosis. We hypothesized that neutralizing monoclonal antibodies (MAbs) targeting the apical complex and surface antigens CSL, GP25-200, and P23 could passively immunize against cryptosporidiosis. We recently reported that a formulation of MAbs 3E2 (anti-CSL), 3H2 (anti-GP25-200), and 1E10 (anti-P23) provided significant additive prophylactic efficacy over that of the individual MAbs in neonatal ICR mice. In the present study, these MAbs were evaluated for therapeutic efficacy against persistent infection in adult gamma interferon-depleted SCID mice. 3E2 demonstrated the most significant and consistent therapeutic effect, reducing intestinal infection in two experiments. In one experiment, 3E2 plus 3H2 and 3E2 plus 3H2 plus 1E10 also significantly reduced infection; however, no significant increase in efficacy over 3E2 alone was apparent. The results indicate that anti-CSL MAb 3E2 has highly significant efficacy in reducing, but not eliminating, persistent C. parvum infection.

scholarly journals Characterization and protective activity of monoclonal antibodies directed against Fe (3+) ABC transporter substrate-binding protein of Glaesserella parasuis

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Kexin Zhu ◽  
Dong Yu ◽  
Jiahui An ◽  
Yufeng Li
Keyword(s):  
Monoclonal Antibodies ◽  
Abc Transporter ◽  
Subunit Vaccine ◽  
Binding Protein ◽  
Substrate Binding ◽  
Passive Immunization ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
And Control ◽  
Substrate Binding Protein

AbstractGlässer’s disease is caused by the agent Glaesserella parasuis and is difficult to prevent and control. Candidate screening for subunit vaccines contributes to the prevention of this disease. Therefore, in this study, the inactivated G. parasuis reference serovar 5 strain (G. parasuis-5) was used to generate specific monoclonal antibodies (mAbs) to screen subunit vaccine candidates. Six mAbs (1A12, 3E3, 4C6, 2D1, 3E6, and 4B2) were screened, and they all reacted with the G. parasuis serovar 5 strain according to laser confocal microscopy and flow cytometry (FCM). Indirect enzyme-linked immunosorbent assay (ELISA) showed that one mAb 2D1, can react with all 15 reference serovars of G. parasuis. Protein mass spectrometry and Western blot analysis demonstrated that mAb 2D1 specifically reacts with Fe (3+) ABC transporter substrate-binding protein. A complement killing assay found that the colony numbers of bacteria were significantly reduced in the G. parasuis-5 group incubated with mAb 2D1 (p < 0.01) in comparison with the control group. Opsonophagocytic assays demonstrated that mAb 2D1 significantly enhanced the phagocytosis of 3D4/21 cells by G. parasuis (p < 0.05). RAW264.7 cells with stronger phagocytic ability were also used for the opsonophagocytic assay, and the difference was highly significant (p < 0.01). Passive immunization of mice revealed that mAb 2D1 can eliminate the bacteria in the blood and provide protection against G. parasuis-5. Our study found one mAb that can be used to prevent and control G. parasuis infection in vivo and in vitro, which may suggest that Fe (3+) ABC transporter substrate-binding protein is an immunodominant antigen and a promising candidate for subunit vaccine development.

Monoclonal antibodies can precipitate low-density lipoprotein. I. Characterization and use in determining apolipoprotein B.

1985 ◽  
Vol 31 (10) ◽  
pp. 1654-1658 ◽  
Author(s):  
S Marcovina ◽  
D France ◽  
R A Phillips ◽  
S J Mao
Keyword(s):  
Monoclonal Antibodies ◽  
Apolipoprotein B ◽  
Polyclonal Antibodies ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Radial Immunodiffusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Density ◽  
Apo B ◽  
Blotting Technique

Abstract We produced 20 mouse monoclonal antibodies against human plasma low-density lipoprotein (LDL). Individually they failed to precipitate LDL in agarose gel by the double-immunodiffusion technique; collectively they did, or as few as two combined monoclonal antibodies could do so. To mimic polyclonal antibodies in determination of apolipoprotein B (apo B) by radial immunodiffusion, a combination of four particular monoclonal antibodies (clones A, B, C, and D) was necessary. We characterized these four clones with respect to temperature dependency, affinity, total binding to 125I-labeled LDL, and specificity to the different species of apolipoprotein B. Two monoclonal antibodies (B and C) bound 100% of 125I-labeled LDL; clones A and D bound 80% and 87%, respectively. All four clones bound maximally to LDL at 4 degrees C. The affinity constants for clones A, B, C, and D were 0.6, 2.1, 3.8, and 2.3 X 10(9) L/mol, respectively. By the Western blotting technique, the four monoclonal antibodies all reacted with the species B-100 and B-74 of apolipoprotein B, and to various degrees with B-48 and B-26. Radial immunodiffusion (chi) and direct enzyme-linked immunosorbent assay (y) with a mixture of the four monoclonal antibodies gave almost identical results for 70 patients: y = 0.921 chi-2.58; r = 0.933.

scholarly journals Development of Murine Monoclonal Antibodies for the Immunohistochemical Diagnosis of Systemic Bovine Aspergillosis

1996 ◽  
Vol 8 (1) ◽  
pp. 68-75 ◽  
Author(s):  
H. E. Jensen ◽  
B. Aalbaek ◽  
P. Lind ◽  
H. V. Krogh ◽  
P. L. Frandsen
Keyword(s):  
Monoclonal Antibodies ◽  
Polyclonal Antibodies ◽  
Fungal Species ◽  
Cross Reactivity ◽  
Water Soluble ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunohistochemical Techniques ◽  
Immunohistochemical Diagnosis ◽  
Murine Monoclonal Antibodies

Murine monoclonal antibodies (MAbs) against water-soluble somatic antigens (WSSA) and the wall fraction (WF) from Aspergillus fumigatus were produced by fusion of splenocytes from immunized BALB/c mice with mouse myeloma X63-Ag 8.653 cells. The supernatants of in vitro cultured hybridomas were initially screened for reactivity with the WSSA and the WF from A. fumigatus and WSSA of other fungi in an enzyme-linked immunosorbent assay (ELISA). Supernatants reacting only with A. fumigatus antigens were subsequently screened for homologous and heterologous reactivity with immunohistochemical techniques using formalin-fixed, paraffin-embedded tissues from experimentally infected mice. Because of a high immunohistochemical reactivity with homologous fungi, 4 MAbs raised against A. fumigatus WSSA and WF were selected for a further evaluation of cross-reactivity (diagnostic specificity) in immunohistochemical and immunoblotting assays. In immunohistochemical assays, all MAbs raised against WSSA cross-reacted heavily with a number of other fungal species. All 4 MAbs (MAb-WF-AF-1-4) raised against the WF reacted strongly with hyphae of Aspergillus spp.; hyphae of Scedosporium apiospermum were also strongly labeled by MAb-WF-AF-3 and-4. The 2 specifically reacting MAbs (MAb-WF-AF-1 and-2) were of the IgM biotype and were precipitating, and in immunoblotting experiments both bound to a 106-kD antigen of the WF, whereas they did not bind to WSSA of A. fumigatus. One of the 2 aspergillosis-specific MAbs (MAb-WF-AF-1) was used to screen 145 mycotic lesions of cattle. The diagnoses on bovine lesions obtained by MAb-WF-AF-1 were compared with results based on reactivity with heterologously absorbed polyclonal antibodies and, for some lesions, to culture results. In the vast majority of lesions ( n = 133), the MAb-WF-AF-1 and the polyclonal anti-Aspergillus antibodies reacted in a similar pattern, i.e., positively in 41 aspergillosis lesions and negatively in 92 zygomycotic lesions. Hyphae in 3 of 12 lesions that were not stained by the polyclonal antibodies reacted with the specific MAb-WF-AF-1; i.e., aspergillosis was diagnosed. The characteristics of the 2 MAbs (MAb-WF-AF-1 and-2) raised against the WF of A. fumigatus in ELISA and immunoblotting and immunohistochemical assays justify their application for the in situ diagnosis of systemic aspergillosis of cattle.

Monoclonal antibodies against plasma protease inhibitors: I. Production and characterization of 23 monoclonal antibodies against human α2

1984 ◽  
Vol 4 (1) ◽  
pp. 39-48 ◽  
Author(s):  
P. Herion ◽  
D. Siberdt ◽  
G. Garduno Soto ◽  
J. Urbain ◽  
A. Bollen
Keyword(s):  
Monoclonal Antibodies ◽  
Protease Inhibitors ◽  
Light Chains ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Fusion Technique ◽  
Epitope Specificity ◽  
Fast Acting ◽  
Inhibition Pattern

23 hybridomas secreting monoclonal antibodies against human α2, the fast-acting inhibitor of plasmin present in plasma, have been produced by the cell-fusion technique. Isotyping of the monoclonal antibodies has revealed that 14 monoclonal antibodies belong to the class IgG1, 6 to the class IgG2a, and 3 to the class tgG2b. All light chains belong to the κ group. The specificity and relative avidity of these monoclonals have been determined Using an indirect enzyme-linked immunosorbent assay. 13 monoclonals exhibit a relatively high avidity for α2, 5 are of intermediate avidity, and 5 of low avidity. The epitope specificity of these 23 rnonoclonal antibodies, originating from a single mouse, have been examined in inhibition experiments. A group of 10 monoclonal antibodies exhibit a very similar inhibition pattern. Partial inhibition effects displayed by 10 other antibodies define partially overlapping antigenic regions. The binding of these antibodies seems to produce a conformational change in the α2 molecule, reducing the binding of two other antibodies. The last antibody defines an independent epitope.

Detection of Abrin in Food Using Enzyme-Linked Immunosorbent Assay and Electrochemiluminescence Technologies

2008 ◽  
Vol 71 (9) ◽  
pp. 1868-1874 ◽  
Author(s):  
ERIC A. E. GARBER ◽  
JENNIFER L. WALKER ◽  
THOMAS W. O'BRIEN
Keyword(s):  
Monoclonal Antibodies ◽  
Immunosorbent Assay ◽  
Dairy Products ◽  
Polyclonal Antibodies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ribosome Inactivating Protein ◽  
Limits Of Detection ◽  
Abrus Precatorius ◽  
A Priority

Abrin is a toxic ribosome-inactivating protein present in beans of Abrus precatorius, also known as rosary peas. The possibility that abrin could be used to adulterate food has made the development of assays for the detection of abrin a priority. Rabbit-derived polyclonal antibodies and mouse monoclonal antibodies were prepared against a mixture of abrin isozymes. The specificity and cross-reactivity of the antibodies were evaluated against a challenge library of 40 grains, nuts, legumes, and foods. An enzyme-linked immunosorbent assay (ELISA) and an electrochemiluminescence (ECL)–based assay were assembled and optimized. Polyclonal (capture) and polyclonal (detection) ELISAs, polyclonal and monoclonal ELISAs, and polyclonal and monoclonal ECL assays had limits of detection (LODs) of 0.1 to 0.5 ng/ml for abrin in buffer. The LOD for abrin dissolved into juices, dairy products, soda, chocolate drink, and condiments and analyzed with the ECL assay ranged from 0.1 to 0.5 ng/ml in the analytical sample. In contrast, the LODs for the ELISAs ranged from 0.5 to 10 ng/ml in the analytical sample.

scholarly journals Development of an Enzyme-Linked Immunosorbent Assay for Serotyping Ureaplasma urealyticum Strains Using Monoclonal Antibodies

2001 ◽  
Vol 8 (1) ◽  
pp. 52-57 ◽  
Author(s):  
Fedoua Echahidi ◽  
Gaëtan Muyldermans ◽  
Sabine Lauwers ◽  
Anne Naessens
Keyword(s):  
Monoclonal Antibodies ◽  
Immunosorbent Assay ◽  
Ureaplasma Urealyticum ◽  
Polyclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa Method ◽  
Cross Reactions ◽  
Antigenic Preparation ◽  
Negative Controls ◽  
Reference Strains

ABSTRACT Ureaplasma urealyticum comprises 14 serotypes. The existing serotyping methods all use polyclonal antibodies. These methods are time-consuming and labor-intensive, and they cannot always be performed on primary isolates; in addition, the results are difficult to interpret. We developed a new enzyme-linked immunosorbent assay (ELISA) method using serotype-specific monoclonal antibodies (MAbs) to enable the serotyping of U. urealyticum isolates from primary broth cultures. Each of the 14 serotype reference strains was tested against 14 selected MAbs. Homologous reactions were very strong, while heterologous reactions were negligible. Three cross-reactions were observed: MAb 5 cross-reacted with serotype 2, MAb 14 cross-reacted with serotype 3, and MAb 8 cross-reacted with serotype 13. Despite the cross-reactions observed, all the serotype reference strains ofU. urealyticum could be identified and differentiated using a combination of MAbs. Reproducibility was analyzed with a fractionated antigenic preparation and with several freshly prepared antigens of the same strain. No significant interrun variation was found with the fractionated antigen, but significant variations in optical density (OD) values were found when freshly prepared antigens were tested. However, the variation in OD values did not influence the overall interpretation of the ELISA: reactions with homologous MAbs were always prominent compared to those of the negative controls. This newly developed ELISA using MAbs seems promising for serotyping of U. urealyticum clinical isolates.

scholarly journals O-Polysaccharide Epitopic Heterogeneity at the Surface of Brucella spp. Studied by Enzyme-Linked Immunosorbent Assay and Flow Cytometry

1998 ◽  
Vol 5 (6) ◽  
pp. 862-870 ◽  
Author(s):  
Axel Cloeckaert ◽  
Vincent Weynants ◽  
Jacques Godfroid ◽  
Jean-Michel Verger ◽  
Maggy Grayon ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Monoclonal Antibodies ◽  
The Other ◽  
Antigenic Structure ◽  
Enzyme Linked Immunosorbent Assay ◽  
Major Goal ◽  
Passive Protection ◽  
Epitope Specificity ◽  
New Information ◽  
High Degree

ABSTRACT Smooth Brucella strains are classified into three serotypes, i.e., A+M−, A−M+, and A+M+, according to slide agglutination with A and M monospecific polyclonal sera. The epitopes involved have been located on the O-polysaccharide (O-PS) moiety of the smooth lipopolysaccharide (S-LPS), which represents the most exposed antigenic structure on the surface ofBrucella spp. By use of monoclonal antibodies (MAbs) a number of epitope specificities on the O-PS have been reported: A, M, and epitopes shared by both A and M dominant strains, which have been named common (C) epitopes. The latter have been further subdivided, according to relative MAb binding in enzyme-linked immunosorbent assays (ELISA) to A- and M-dominant Brucella strains and to cross-reacting Yersinia enterocolitica O:9, into five epitopic specificities: C (M>A), C (M=A), C/Y (M>A), C/Y (M=A), and C/Y (A>M). In the present study, we studied the occurrence of these epitopes at the surface of representatives of all Brucellaspecies and biovars including the live vaccine strains by analyzing the levels of MAb binding to whole Brucella cells in ELISA and flow cytometry assays. In ELISA, the level of MAb binding correlated well with the previously defined epitope specificity and the serotype defined by polyclonal sera for each Brucella species, biovar, or strain. However, MAbs to the C (M=A) and C (M>A) epitopes showed insignificant binding to B. suis biovar 2 strains and bound at lower titers to B. suis biovar 3 and B. neotomae than to the other Brucella strains. Some of the flow cytometry results were contradictory to those obtained by ELISA. In fact, it appeared by flow cytometry that all O-PS epitopes, including the A and M epitopes, are shared to different degrees byBrucella spp. which nevertheless show a high degree of O-PS heterogeneity according to MAb binding intensities. The subdivision of MAb specificities and Brucella serotypes was therefore less evident by flow cytometry than by ELISA. Whereas in ELISA the MAb specific for the A epitope showed insignificant binding to Y. enterocolitica O:9, this MAb bound strongly to Y. enterocolitica O:9 in flow cytometry. One of the two MAbs specific to the C (M=A) epitope also bound at a low but significant level to B. suis biovar 2 strains. However, as in ELISA the MAb specific for the C (M>A) epitope did not bind at all to B. suis biovar 2 strains in flow cytometry. Flow cytometry provided new information regarding specificity of the MAbs and may further explain some aspects of the capacity of passive protection of some MAbs against smooth Brucella infection in mice. As shown in the present study the occurrence of Brucella strains apparently completely devoid of one specific C O-PS epitope (e.g., B. suis biovar 2 devoid of the C [M>A] epitope) offers the possibility of obtaining vaccine strains devoid of a diagnostic O-PS epitope, which could further help to resolve the problem of discriminating infected from vaccinated animals that remains a major goal in brucellosis research.

scholarly journals Role of Immunoglobulin A Monoclonal Antibodies against P23 in Controlling Murine Cryptosporidium parvum Infection

1998 ◽  
Vol 66 (9) ◽  
pp. 4469-4473 ◽  
Author(s):  
F. Javier Enriquez ◽  
Michael W. Riggs
Keyword(s):  
Monoclonal Antibodies ◽  
Cryptosporidium Parvum ◽  
Matched Control ◽  
Intestinal Parasites ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Immunoglobulin A ◽  
Passive Immunization ◽  
Immunofluorescence Assay

ABSTRACT Cryptosporidium parvum is an important diarrhea-causing protozoan parasite of immunocompetent and immunocompromised hosts. Immunoglobulin A (IgA) has been implicated in resistance to mucosal infections with bacteria, viruses, and parasites, but little is known about the role of IgA in the control of C. parvuminfection. We assessed the role of IgA during C. parvum infection in neonatal mice. IgA-secreting hybridomas were developed by using Peyer’s patch lymphocytes from BALB/c mice which had been orally inoculated with viable C. parvumoocysts. Six monoclonal antibodies (MAbs) were selected for further study based on indirect immunofluorescence assay reactivity with sporozoite and merozoite pellicles and the antigen (Ag) deposited on glass substrate by gliding sporozoites. Each MAb was secreted in dimeric form and recognized a 23-kDa sporozoite Ag in Western immunoblots. The Ag recognized comigrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with P23, a previously defined neutralization-sensitive zoite pellicle Ag. MAbs were evaluated for prophylactic or therapeutic efficacy against C. parvum, singly and in combinations, in neonatal BALB/c mice. A combination of two MAbs given prophylactically prior to and 12 h following oocyst challenge reduced the number of intestinal parasites scored histologically by 21.1% compared to the numbers in mice given an isotype-matched control MAb (P < 0.01). Individual MAbs given therapeutically in nine doses over a 96-h period following oocyst challenge increased efficacy against C. parvuminfection. Four MAbs given therapeutically each reduced intestinal infection 34.4 to 42.2% compared to isotype-matched control MAb-treated mice (P < 0.05). One MAb reduced infection 63.3 and 72.7% in replicate experiments compared to isotype-matched control MAb-treated mice (P < 0.0001). We conclude that IgA MAbs directed to neutralization-sensitive P23 epitopes may have utility in passive immunization against murineC. parvum infection.

scholarly journals Production of Monoclonal Antibodies Specific for the i and 1,2 Flagellar Antigens of Salmonella typhimurium and Characterization of Their Respective Epitopes

1998 ◽  
Vol 64 (12) ◽  
pp. 5033-5038 ◽  
Author(s):  
N. de Vries ◽  
K. A. Zwaagstra ◽  
J. H. J. Huis in’t Veld ◽  
F. van Knapen ◽  
F. G. van Zijderveld ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Salmonella Typhimurium ◽  
Immunosorbent Assay ◽  
Specific Antibody ◽  
Polyclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specific Antibodies ◽  
Minimal Area

ABSTRACT Salmonella typhimurium expresses two antigenically distinct flagellins, each containing a different H antigen (i and 1,2), the combination of which is highly specific for this serotype. In this study, overlapping recombinant flagellin fragments were constructed from the fliC(H:i) and fljB (H:1,2) flagellin genes, and the expression products were tested for binding to H antigen-specific monoclonal and polyclonal antibodies. A minimal area, 86 amino acids for H:i and 102 amino acids for H:1,2, located in the central variable domain of each flagellin was required for the binding of serotype-specific antibodies, providing further evidence for the presence of a discontinuous H epitope. Two peptides comprising these areas were shown to be highly suitable for application as antigens in an enzyme-linked immunosorbent assay detecting S. typhimurium-specific antibody.

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