Use of IgY antibodies and semiconductor nanocrystal detection in cancer biomarker quantitation.
ABSTRACT Biomarkers play a pivotal role in the early detection and diagnosis of cancer. Accurate quantitation of certain biomarkers is crucial to reach correct treatment decisions. In practice, immunohistochemistry (IHC) remains the most important diagnostic technique to evaluate protein biomarker expression in tissue biopsies. However, IHC has largely been qualitative. Low specificity of the mammalian IgG antibodies used to capture the analytes and instability of fluorescence from the organic dyes used as the detecting agents are among the major factors that have impeded the development of quantitative IHC. Avian IgY antibodies have many attractive biochemical, immunological and production advantages over IgGs and are, therefore, better substitutes in diagnostic applications. Using IgY in immunoassays can potentially eliminate false positives and often results in low background and interference. Quantum dots (QDs) have recently emerged as a novel class of fluorophores, promising for many biomedical imaging applications. Fluorescence from QDs is significantly brighter and more photostable than organic dyes. In addition, QDs offer the capacity of multiplexed detection of several biomarkers simultaneously. Combining the high sensitivity and specificity of IgY antibodies and the high brightness and photostability of QDs in IHC has been demonstrated to improve biomarker detection and quantitation.
Article: Production, characterization and applications for Toxoplasma gondii-specific polyclonal chicken egg yolk immunoglobulins.[show abstract] [hide abstract]
ABSTRACT: Toxoplasma gondii may cause abortions, ocular and neurological disorders in warm-blood hosts. Immunized mammals are a wide source of hyperimmune sera used in different approaches, including diagnosis and the study of host-parasite interactions. Unfortunately, mammalian antibodies present limitations for its production, such as the necessity for animal bleeding, low yield, interference with rheumatoid factor, complement activation and affinity to Fc mammalian receptors. IgY antibodies avoid those limitations; therefore they could be an alternative to be applied in T. gondii model. In this study we immunized hens with soluble tachyzoite antigens of T. gondii (STAg) and purified egg yolk antibodies (IgY) by an inexpensive and simple method, with high yield and purity degree. IgY anti-STAg antibodies presented high avidity and were able to recognize a broad range of parasite antigens, although some marked differences were observed in reactivity profile between antibodies produced in immunized hens and mice. Interestingly, IgY antibodies against Neospora caninum and Eimeria spp. did not react to STAg. We also show that IgY antibodies were suitable to detect T. gondii forms in paraffin-embedded sections and culture cell monolayers. Due to its cost-effectiveness, high production yield and varied range of possible applications, polyclonal IgY antibodies are useful tools for studies involving T. gondii.PLoS ONE 01/2012; 7(7):e40391. · 4.09 Impact Factor