Clinical Trial in a Well
VaxDesign is developing a “clinical trial in a well” that mirrors the human immune response with a high-throughput process. By simulating the human immune system responses in our laboratory, we make rapid, clinically relevant predictions dramatically reducing the cost and time required to bring new immunotherapies and vaccines to market.
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A Four-Step Process
Our process has four steps, each one equating to a step in the human immune system process:
| Human Immune Process | Clinical Trial in a Well | |
|---|---|---|
| 1 | Blood | Blood Collection via Apheresis |
| 2 | Innate responses | Vaccination Site |
| 3 | Adaptive responses | Lymphoid Tissue Equivalent (LTE) |
| 4 | Protection | Functional Assays |
A highlight of activity at VaxDesign is the alpha-omega characterization of immune response to vaccines thereby creating a “clinical trial in a test tube.” Below, we discuss influenza as an example of this alpha to omega immune response characterization. The in vitro system designed is comprised of three main modules that represent innate immune responses, adaptive immune responses and functional assays. Here we have employed both trivalent inactivated (Flumist™) and cold-adapted live-attenuated trivalent vaccines (Flumist™). Using these vaccine formulations we have been able to generate representative innate responses via activating antigen-presenting cells (APC) in the first module, the Vaccination Site. Antigen pulsed APCs, are then cultured with autologous T and B lymphocytes in defined proportions and kinetics in the adaptive immune response module. In this manner, we have been able to generate influenza-specific IgG antibody secreting cells. Next, the supernatants derived from these cultures were shown to possess inhibitory titers when used in hemagglutin in inhibition functional and microneutralization assays. In this way, the in vitro immunological model has been able to correspond to a bona fide immune response that is representative of in vivo responses.
In the clinical trial in a well, characterize these immunocytesand biomolecules using a wide range of assays such as ELISA, ELISpot, ICCS, cytotoxicT cell, and neutralizing antibody assays.
Using antibody responses an example, we can determine:
- Class
- Subtype
- Subclass
- Specificity,
- virus neutralization, and
- Any other customer specifications.
For antibody responses, we measure whether the vaccine elicits neutralization of the virus.
Another major focus was the development of a sensitive indicator for the presence of cytotoxic T lymphocytes resulting from co-incubation of dendritic cells (DCs) pulsed with various vaccines, vaccine antigens or peptides with purified T cell populations. The flow cytometric approach allows detection of low frequency of responding cytotoxic T lymphocytes (CTL) within the population. The analysis is based on the dual expression of the markers CD107a (LAMP1-lysosomal associated membrane glycoprotein 1) and IFN-γ by CD8+ T cells in response to appropriately primed antigen-presenting cells. LAMP proteins are located in the core of preformed lytic granules containing granzyme and perforin and they appear at the surface of the cell upon degranulation. Thus monitoring the presence of CD107a gives an indication of the T cell’s ability to degranulate. IFN-γ production is commonly used as an inidicator of CTL response to antigen presenting cells (APCs) presenting cognate peptide. A combination of the two markers provides a stringent test for determination of an antigen-specific response.
Experiments have been conducted using various protein antigens and, Flumist™ live-attenuated vaccine as challenge antigens. The response to the attenuated virus was robust as can be seen with high levels of CD107a and IFN-γ.
Evaluation of CTL Responses: Flumist®