Compositions and methods for detecting Loa loa
Inventors
Nutman, Thomas B. • BENNURU, Sasisekhar • Drame, Papa Makhktar
Assignees
US Department of Health and Human Services
Publication Number
US-10598655-B2
Publication Date
2020-03-24
Expiration Date
2036-04-28
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Abstract
Disclosed are methods of detecting the presence of Loa loa in a biological sample using one or more antigens, each having a different amino acid sequence selected from the group consisting of SEQ ID NOs: 1-20. Related compositions, specific binding partners, and test kits are also disclosed.
Core Innovation
Loa loa is a filarial nematode infecting millions in central and western Africa, causing loiasis. Although often asymptomatic, loiasis presents a significant public health concern due to severe adverse reactions, including fatal encephalopathies, in Loa-infected individuals treated with ivermectin during mass drug administration programs for other filarial diseases. This has led to disruption of such programs in co-endemic areas. Current detection methods like microscopic evaluation, PCR, and LAMP are impractical for widespread screening due to their need for sophisticated instrumentation.
The invention provides improved methods and compositions for detecting Loa loa in biological samples by assaying for one or more antigens with distinct amino acid sequences selected from SEQ ID NOs: 1-20. Detection of at least one of these antigens indicates the presence of Loa loa. The invention also includes methods to detect antibodies that specifically bind to these antigens and compositions comprising immunologically-stimulatory concentrations of these antigens for producing antibodies. Specific binding partners targeting these antigens and test kits designed for detection using these specific interactions are further provided.
These Loa loa antigens are believed to be unique to the parasite's microfilariae and absent from related filarial parasites. They are detectable in infected biological samples and undetectable in uninfected samples, supporting their use as biomarkers. Methods such as ELISA, LIPS, immunoprecipitation, and lateral flow assays employing specific binding partners enable sensitive and specific detection. The approaches are more rapid and practical than existing techniques, especially for resource-limited regions.
Claims Coverage
This patent contains 28 claims with multiple independent claims covering methods of detecting Loa loa antigens or antibodies, compositions for antibody production, and test kits. The main inventive features involve specific amino acid sequences and the use of specific binding partners in detection methods.
Method of detecting Loa loa antigens with selected amino acid sequences
A method of detecting one or more Loa loa antigens in a biological sample, each antigen having an amino acid sequence selected from SEQ ID NOs: 1, 4, 14, and 15, wherein presence of at least one antigen indicates Loa loa in the subject.
Method involving multiple antigen detection
Assaying the biological sample to determine presence of two or more antigens, each with different amino acid sequences from SEQ ID NOs: 1, 4, 14, and 15, with detection of at least two indicating Loa loa infection.
Use of specific binding partners to detect antigen complexes
Contacting the biological sample with one or more specific binding partners, each binding specifically to different amino acid sequences from SEQ ID NOs: 1, 4, 14, and 15, forming complexes whose detection indicates Loa loa presence.
Antibody or antigen binding fragment as specific binding partner
The specific binding partners used in detection methods are antibodies or antigen-binding fragments thereof.
Detecting multiple antigen complexes with multiple binding partners
Contacting the sample with two or more specific binding partners, each targeting different amino acid sequences from SEQ ID NOs: 1, 4, 14, and 15, to form and detect multiple complexes indicative of Loa loa.
Two-step binding assay using first and second specific binding partners
A method comprising (a) contacting the sample with a first specific binding partner forming a first complex, (b) contacting the first complex with a second specific binding partner forming a second complex, and (c) detecting the second complex as indicative of Loa loa.
Detection of antibodies specific to Loa loa antigens
Assaying a biological sample to detect one or more antibodies that specifically bind to antigens having amino acid sequences from SEQ ID NOs: 1, 4, 14, and 15, indicating Loa loa presence.
Immunoassay methods for detection
Assaying is performed by methods such as immunoprecipitation, immunonephelometry, radioimmunoassay, enzyme immunoassay, fluorescent immunoassay, luciferase immunoprecipitation system, lateral flow assay, with ELISA especially preferred.
Compositions for antibody production comprising specific antigens and adjuvants
Compositions comprising immunologically-stimulatory concentrations of isolated or purified antigens selected from SEQ ID NOs: 1, 4, 14, and 15, physiologically acceptable carriers, and adjuvants to induce antibody production.
Methods for producing specific antibodies in animals
Administering the above compositions to animals under conditions sufficient to evoke immune responses producing antibodies specific to the indicated antigens, followed by harvesting sera or hybridomas secreting such antibodies.
Test kits for detecting Loa loa antibodies
Test kits comprising one or more antigens from SEQ ID NOs: 1, 4, 14, and 15 bound or affixed to substrates, with reagents facilitating antibody binding and detection.
The claims primarily cover methods for detecting Loa loa in biological samples by identifying specific antigens or antibodies targeting antigens having defined amino acid sequences. They also include compositions for antibody generation and test kits employing these antigens and specific binding partners to enable practical, sensitive, and specific detection of Loa loa.
Stated Advantages
The inventive methods and compositions may detect Loa loa more rapidly than existing techniques such as microscopic evaluation, RT-PCR, and LAMP.
The inventive methods and compositions may not require sophisticated instrumentation, making them suitable for widescale screening, particularly in resource-limited areas.
Documented Applications
Detection of Loa loa infection in a biological sample from a subject by assaying for Loa loa-specific antigens or antibodies.
Producing antibodies in animals by administering compositions comprising selected Loa loa antigens.
Using test kits comprising Loa loa antigens or specific binding partners for detection of Loa loa infection in biological samples.
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