Cryptococcal Antigen Testing
Cryptococcal Antigen Testing - Related Videos
01:27
Cryptococcal Meningitis
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2026
Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii,...
06:57
Development of an Antigen-driven Colitis Model to Study Presentation of Antigens by Antigen Presenting Cells to T Cells
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Cited by 9 •
2016
In this antigen-driven colitis model, OT-II CD4+ T cells expressing a red fluorescent protein were adoptively transferred into RAG-/- mice that express a green fluorescent protein in mononuclear phagocytes (MPs). The hosts were challenged with Escherichia coli (E.coli) expressing the ovalbumin protein (OVA) fused to a cyan fluorescent protein (CFP).
05:04
Viral Antigen Microarray Assay to Detect Antibody Isotypes in Serum Against Viral Antigen
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2025
In this video, we demonstrate the process for detecting antibody isotypes in multiple human serum samples using a microarray slide printed with antigenic subtypes of influenza virus strains.
08:08
Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body
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Cited by 18 •
2018
This technique describes an automated batch image processor designed to measure polysaccharide capsule and body radii. While initially designed for Cryptococcus neoformans capsule measurements the automated image processor can also be applied to other contrast based detection of circular objects.
08:32
Extraction of Tissue Antigens for Functional Assays
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2012
A simple protocol for preparing extracts of human tissue to be used as a source of antigens in functional T-cell assays is described. This method allows T-cell responses to tissue-derived antigens to be measured in vitro.
FAQs
The assay relies on specific antibodies recognizing capsular polysaccharide released by Cryptococcus species. When the patient specimen is exposed to those antibodies, antigen-antibody binding produces a visible reaction through either a lateral flow format or agglutination. This molecular recognition step converts the presence of a pathogen-associated component into an observable laboratory result.
A titer provides more information than a simple positive or negative signal by reporting the concentration of cryptococcal antigen detected in the specimen. Because antigen concentration can be expressed this way, the result offers a semi-quantitative measure for evaluating the laboratory finding and supporting decisions about additional testing or clinical management.
Antigen testing can identify cryptococcal infection before or alongside culture-based diagnosis, giving investigators and clinicians an additional diagnostic route. Culture remains a separate laboratory approach, whereas antigen testing detects a pathogen-produced molecular marker. Using both perspectives can support evaluation when rapid antigen evidence and culture findings need to be considered together.
Serum and cerebrospinal fluid provide specimen types for exposing suspected patient material to the assay’s specific antibodies. Cerebrospinal fluid is particularly relevant when cryptococcal meningitis is being evaluated, while serum can contribute to assessment of infection more broadly. The selected specimen therefore connects the laboratory measurement with the suspected anatomical or systemic context.
The test is especially useful when clinicians are evaluating possible cryptococcal meningitis or disseminated infection, including situations involving advanced immunosuppression. Its rapid antigen signal can support early diagnostic assessment before or alongside culture results. The information may also help guide confirmatory testing and clinical management in patients at elevated risk of serious disease.
This testing approach illustrates how a biological product, the cryptococcal capsular polysaccharide, can function as a diagnostic marker. Specific antibody recognition links molecular interaction to a visible laboratory signal and, when reported as a titer, to an estimate of antigen concentration. The example shows how pathogen biology can be translated into practical diagnostic information.