In vitro germinal centers
The present invention incorporates germinal centers (GCs) into three-dimensional (3D) engineered tissue constructs (ETCs). In an embodiment, we have incorporated the GC in the design of an artificial immune system (AIS) to examine immune responses to vaccines and other compounds. Development of an in vitro GC adds functionality to an AIS, in that it enables generation of an in vitro human humoral response by human B lymphocytes that is accurate and reproducible, without using human subjects. The invention also permits evaluation of, for example, vaccines, allergens, and immunogens, and activation of human B cells specific for a given antigen, which can then be used to generate human antibodies. In an embodiment of the present invention the function of the in vitro GC is enhanced by placing FDCs and other immune cells in a 3D ETC; FDCs appear more effective over a longer time (antibody production is sustained for up to about 14 days.
1. An in vitro cellular system comprising a culture comprising
an engineered tissue construct; and
at least one three-dimensional artificial germinal center embedded in or fixed on the engineered tissue construct, said artificial germinal center comprising follicular dendritic cells; B cells; and T cells.
2. The in vitro cellular system of claim 1 wherein said engineered tissue construct is selected from the group consisting of a collagen cushion, gelatin, hyaluronic acid, small intestine submucosa, urinary bladder mucosa, PLGA, a hydrogel, and a tissue culture plate coated with collagen, microcarriers, inverted colloid crystal matrices, synthetic extracellular matrix materials, or natural extracellular matrix materials.
3. The in vitro cellular system of claim 1 wherein said B cells and T cells are isolated from an individual immunized with an agent selected from the group consisting of a vaccine, an adjuvant, an immunomodulator, an immunotherapy candidate, a cosmetic, a drug, a biologic, and a chemical compound.
4. The in vitro cellular system of claim 1 , wherein said culture further comprises follicular leukocytes.
5. The in vitro cellular system of claim 1 , wherein said culture comprising an engineered tissue construct comprises a tissue culture plate coated with collagen spots.
6. The in vitro cellular system of claim 5 , wherein said collagen spots are crosslinked.
7. The in vitro cellular system of claim 5 , wherein said follicular dendritic cells are adhered to the collagen spots.
8. The in vitro cellular system of claim 1 , wherein said system further comprises stromal cells distributed in the engineered tissue construct.
9. The in vitro cellular system of claim 1 , wherein said culture further comprises soluble factors selected from the group consisting of IL-4, CD40L, and anti-CD40 antibodies.
10. The in vitro cellular system of claim 1 , wherein said culture further comprises an agent selected from the group consisting of a vaccine, an adjuvant, an immunomodulator, an immunotherapy candidate, a cosmetic, a drug, a biologic, and a chemical compound.