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HIGHLY SENSITIVE TEST FOR DETECTION OF ANTIGEN-SPECIFIC T CELL RESPONSES
Background: Exposure to HIV, other viral and some bacterial and parasite diseases is detected by assays that measure immune responses in vitro. The enzyme-linked immunosorbent spot assay (ELISPOT) assay has become widely used as a tool for the detection of these cellular and humoral immune responses. Although the sensitivity and technical ease of the ELISPOT assay make it a useful alternative to traditional analytical methods, there remains a need for increased sensitivity to detect low level antigen-specific T cell responses in patients that have been difficult to diagnose by standard methods.
The addition of autologous dendritic cells has been shown to augment the sensitivity of ELISPOT assays. However, this method requires large amounts of fresh peripheral blood and in vitro maturation of monocytes over a period of 5 to 7 days. It is therefore desirable to identify a combination of cytokines and/or co-stimulatory molecules that are able to substitute for the potent antigen-presenting capability of mature dendritic cells. Description: Researchers at the University of California have discovered that addition of the gamma-c cytokines IL-7 and IL-15 significantly enhances the sensitivity of the ELISPOT assay. Sensitivity in fresh samples was augmented up to 7.5-fold, and, using cryopreserved specimens, sensitivity was augmented up to 18-fold. Applications: Increasing the sensitivity of the ELISPOT assay will prove useful for: - Quantification of antigen-specific T cells in the setting of longitudinal clinical studies, in which only cryopreserved samples are available.
- Subjects with low level HIV-specific T cell responses that have been difficult to detect by standard methods. These subjects include individuals exposed to HIV but who remain uninfected, HIV patients on pharmaceutical regimens with suppressed viral load and subsequent diminished T cell responses, and patients with very low T cell counts resulting in antigen unresponsiveness.
- Detection of other viral, bacterial, or other infectious agents.
- Detection of tumors or autoimmune antigens in instances where low level responses may be overlooked by standard methods.
Advantages:
- Addition of both IL-7 and IL-15 substitutes for the addition of mature dendritic cells. Use of these cytokines relieves the requirements for large quantities of fresh peripheral blood as well as the 5-7 day time period for the in vitro maturation of monocytes.
- Use of IL-7 and IL-15 greatly increases the sensitivity of the ELISPOT assay for cryopreserved samples. Such samples exhibit very low antigenicity when assayed using other techniques.
Gladstone Contact:
Caryl Cachola
Telephone: 415-734-2082  Tell a friend
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