A mosquito AgTRIO monoclonal antibody reduces early Plasmodium infection of mice

2021 ◽  
Author(s):  
Yu-Min Chuang ◽  
Xu-Dong Tang ◽  
Erol Fikrig

Malaria begins when an infected mosquito injects saliva containing Plasmodium sporozoites into the skin of a vertebrate host. Passive immunization of mice with mosquito AgTRIO antisera offers significant protection against Plasmodium infection of mice. Furthermore, passive transfer of both AgTRIO antisera and an anti-circumsporozoite protein monoclonal antibody provides synergistic protection. In this study, we generated monoclonal antibodies against AgTRIO to delineate the regions of AgTRIO associated with protective immunity. Monoclonal antibody 13F-1 markedly reduced Plasmodium infection in mice and recognized a region, VDDLMAKFN, in the carboxyl terminus of AgTRIO. 13F-1 is an IgG2a isotype monoclonal antibody and the Fc region is required for protection. These data will aid in the generation of future malaria vaccines that may include both pathogen and vector antigens.

1993 ◽  
Vol 39 (4) ◽  
pp. 583-591 ◽  
Author(s):  
M J Hursting ◽  
B T Butman ◽  
J P Steiner ◽  
B M Moore ◽  
M C Plank ◽  
...  

Abstract Prothrombin fragment 1.2 (F1.2) is an activation peptide generated during a critical event of blood coagulation, the conversion of prothrombin to thrombin. As a marker of thrombin generation, F1.2 has clinical potential in assessing thrombotic risk and monitoring anticoagulant therapy. In developing a highly specific, monoclonal antibody-based immunoassay of human plasma F1.2, we generated six murine anti-F1.2 monoclonal antibodies, using as immunogen a synthetic peptide (sequence: CGSD-RAIEGR) similar to the unique carboxyl terminus of F1.2. Each antibody bound F1.2 but not prothrombin. Epitope mapping studies with one antibody (5-3B) showed that optimum binding required six to eight amino acids plus a terminal arginine to emulate the F1.2 carboxyl terminus. A quantitative sandwich ELISA for human plasma F1.2 was configured with monoclonal antibody 5-3B as the capture antibody and peroxidase-labeled polyclonal antibodies to the F1.2 amino-terminal region as detector antibodies. Calibrators were prepared by adding purified F1.2, 0-10 nmol/L, to F1.2-depleted plasma. Assay characteristics included the following: mean (+/- SD) analytical recovery of 98% +/- 13%; no interference from lipemia, hemolysis, icterus, or thrombolytic agents; 0.08 nmol/L sensitivity; and mean intra- and interassay imprecision (three lots) < 12% at both low and high concentrations of F1.2.


2003 ◽  
Vol 10 (5) ◽  
pp. 903-909 ◽  
Author(s):  
Suzanne Brandt ◽  
Peter Thorkildson ◽  
Thomas R. Kozel

ABSTRACT Cryptococcus neoformans is surrounded by an antiphagocytic capsule whose primary constituent is glucuronoxylomannan (GXM). An epitope shared by GXM serotypes A, B, C, and D is immunodominant when mice are immunized with serotype A GXM. In contrast, an epitope shared only by serotypes A and D is immunodominant when mice are immunized with serotype D. Hybridomas secreting antibodies reactive with subdominant epitopes were identified through a positive-negative screening procedure in which antibody-secreting colonies were characterized by reactivity with both the immunizing polysaccharide and GXMs from each of the four major serotypes. In this manner, a monoclonal antibody (MAb) that was reactive with an epitope shared only by serotypes A and B was identified and designated F10F5. Such an epitope has not been described previously. Immunization of mice with de-O-acetylated serotype A GXM generated a hybridoma that secreted an antibody, designated F12D2, that was reactive with all four serotypes. Unlike previously described monoclonal and polyclonal panspecific antibodies, the reactivity of MAb F12D2 was not altered by de-O-acetylation of GXM. These results indicate that there are at least two panspecific GXM epitopes; one epitope is dependent on O acetylation for antibody reactivity, and the other is independent of O acetylation. This study identifies strategies for production of MAbs that are reactive with subdominant or cryptic GXM epitopes and provides new information regarding the antigenic makeup and the humoral immune response to GXM, an essential virulence factor that is a target for active and passive immunization.


1987 ◽  
Vol 57 (02) ◽  
pp. 212-216 ◽  
Author(s):  
L I Thorsen ◽  
G Gaudernack ◽  
F Brosstad ◽  
T M Pedersen ◽  
N O Solum

SummaryA method is described for the identification of antigens by monoclonal antibodies. This is applicable whenever precipitating antibodies to the same antigens from a different species are available. The method is based upon: 1) Separation and immunoprécipitation of cellular proteins with a polyspecific antiserum in crossed immunoelectrophoresis in the presence of the non-denaturing detergent Triton X-100 and the monoclonal antibody. 2) Coprecipitation of the monoclonal antibody with its antigen. 3) Subsequent passive transfer of the monoclonal antibody in the antibody-antigen complex onto a nitrocellulose membrane. 4) Visualization of the blotted antibody using an enzyme-linked secondary antibody and a chromogenic substrate. 5) Identification of the corresponding antigen by comparisons to the immunoprecipitate pattern of the original immunoplate. To test this method we have analyzed the detection of the antigens recognized by six previously described monoclonal antibodies against platelet membrane proteins and von Willebrand factor. Specific immunoblots were obtained in each case using small amounts of monoclonal antibodies. Thus, the technique provides an alternative when epitopes are denatured by SDS, and avoids the use of radioactively labelled monoclonal antibodies.


1988 ◽  
Vol 66 (1) ◽  
pp. 7-12 ◽  
Author(s):  
I.J. East ◽  
E.A. Washington ◽  
P.J. Brindley ◽  
G.F. Monroy ◽  
N. Scott-Young

2007 ◽  
Vol 75 (11) ◽  
pp. 5443-5452 ◽  
Author(s):  
Herman F. Staats ◽  
S. Munir Alam ◽  
Richard M. Scearce ◽  
Shaun M. Kirwan ◽  
Julia Xianzhi Zhang ◽  
...  

ABSTRACT Passive transfer of antibody may be useful for preexposure prophylaxis against biological agents used as weapons of terror, such as Bacillus anthracis. Studies were performed to evaluate the ability of anthrax antiprotective antigen (anti-PA) and antilethal factor (anti-LF) neutralizing monoclonal antibodies (mAbs) to protect against an anthrax lethal toxin (LeTx) challenge in a mouse model and to identify correlates of immunity to LeTx challenge. Despite having similar affinities for their respective antigens, anti-PA (3F11) and anti-LF (9A11), passive transfer of up to 1.5 mg of anti-PA 3F11 mAb did not provide significant protection when transferred to mice 24 h before LeTx challenge, while passive transfer of as low as 0.375 mg of anti-LF 9A11 did provide significant protection. Serum collected 24 h after passive transfer had LeTx-neutralizing activity when tested using a standard LeTx neutralization assay, but neutralization titers measured using this assay did not correlate with protection against LeTx challenge. However, measurement of LeTx-neutralizing serum responses with an LeTx neutralization assay in vitro employing the addition of LeTx to J774A.1 cells 15 min before the addition of the serum did result in neutralization titers that correlated with protection against LeTx challenge. Our results demonstrate that only the LeTx neutralization titers measured utilizing the addition of LeTx to J774A.1 cells 15 min before the addition of sample correlated with protection in vivo. Thus, this LeTx neutralization assay may be a more biologically relevant neutralization assay to predict the in vivo protective capacity of LeTx-neutralizing antibodies.


Vaccine ◽  
2002 ◽  
Vol 20 (15) ◽  
pp. 1956-1960 ◽  
Author(s):  
Weidong Xu ◽  
Regina Hofmann-Lehmann ◽  
Harold M McClure ◽  
Ruth M Ruprecht

2000 ◽  
Vol 41 (4-5) ◽  
pp. 301-308 ◽  
Author(s):  
N. Noda ◽  
H. Ikuta ◽  
Y. Ebie ◽  
A. Hirata ◽  
S. Tsuneda ◽  
...  

Fluorescent antibody technique by the monoclonal antibody method is very useful and helpful for the rapid quantification and in situ detection of the specific bacteria like nitrifiers in a mixed baxterial habitat such as a biofilm. In this study, twelve monoclonal antibodies against Nitrosomonas europaea (IFO14298) and sixteen against Nitrobacter winogradskyi (IFO14297) were raised from splenocytes of mice (BALB/c). It was found that these antibodies exhibited little cross reactivity against various kinds of heterotrophic bacteria. The direct cell count method using monoclonal antibodies could exactly detect and rapidly quantify N. europaea and N. winogradskyi. Moreover, the distribution of N. europaea and N. winogradskyi in a biofilm could be examined by in situ fluorescent antibody technique. It was shown that most of N. winogradskyi existed near the surface part and most of N. europaea existed at the inner part of the polyethylene glycol (PEG) gel pellet, which had entrapped activated sludge and used in a landfill leachate treatment reactor. It was suggested that this monoclonal antibody method was utilized for estimating and controlling the population of nitrifying bacteria as a quick and favorable tool.


2020 ◽  
Vol 20 (16) ◽  
pp. 1895-1907
Author(s):  
Navgeet Kaur ◽  
Anju Goyal ◽  
Rakesh K. Sindhu

The importance of monoclonal antibodies in oncology has increased drastically following the discovery of Milstein and Kohler. Since the first approval of the monoclonal antibody, i.e. Rituximab in 1997 by the FDA, there was a decline in further applications but this number has significantly increased over the last three decades for various therapeutic applications due to the lesser side effects in comparison to the traditional chemotherapy methods. Presently, numerous monoclonal antibodies have been approved and many are in queue for approval as a strong therapeutic agent for treating hematologic malignancies and solid tumors. The main target checkpoints for the monoclonal antibodies against cancer cells include EGFR, VEGF, CD and tyrosine kinase which are overexpressed in malignant cells. Other immune checkpoints like CTLA-4, PD-1 and PD-1 receptors targeted by the recently developed antibodies increase the capability of the immune system in destroying the cancerous cells. Here, in this review, the mechanism of action, uses and target points of the approved mAbs against cancer have been summarized.


2020 ◽  
Vol 7 (2) ◽  
pp. 121-133
Author(s):  
Ayesha Akhtar ◽  
Shivakumar Arumugam ◽  
Shoaib Alam

Background:: Protein A affinity chromatography is often employed as the most crucial purification step for monoclonal antibodies to achieve high yield with purity and throughput requirements. Introduction:: Protein A, also known as Staphylococcal protein A (SPA) is found in the cell wall of the bacteria staphylococcus aureus. It is one of the first discovered immunoglobulin binding molecules and has been extensively studied since the past few decades. The efficiency of Protein A affinity chromatography to purify a recombinant monoclonal antibody in a cell culture sample has been evaluated, which removes 99.0% of feed stream impurities. Materials and Method:: We have systematically evaluated the purification performance by using a battery of analytical methods SDS-PAGE (non-reduced and reduced sample), Cation Exchange Chromatography (CEX), Size-exclusion chromatography (SEC), and Reversed phased-Reduced Chromatography for a CHO-derived monoclonal antibody. Results and Discussion:: The analytical test was conducted to determine the impurity parameter, Host Cell Contaminating Proteins (HCP). It was evaluated to be 0.015ng/ml after the purification step; while initially, it was found to be 24.431ng/ml. Conclusion:: The tests showed a distinct decrease in the level of different impurities after the chromatography step. It can be concluded that Protein A chromatography is an efficient step in the purification of monoclonal antibodies.


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