養子細胞移植:宿主マウスへのドナーマウス脾細胞導入とFACSによる成功評価
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Q1: What is adoptive cell transfer and why is it used in research?
Adoptive cell transfer is a method for introducing cells into an organism to study biological mechanisms or treat disease. It enables researchers to examine specific immune cell functions, study hematopoiesis, and test novel therapies like cancer treatments where patient T-cells are extracted, modified to recognize tumors, and returned to fight cancer. Animal models allow detailed investigation of transferred cell behavior and efficacy.
Q2: Why are CD45.1 Rag gamma-c knockout mice used in adoptive transfer studies?
CD45.1 Rag gamma-c knockout mice lack fundamental cytokine receptors essential for normal lymphocyte development, resulting in compromised immune systems without natural killer cells, T-cells, or B-cells. These immunocompromised mice serve as ideal recipients for adoptive transfer because they allow researchers to study how donor immune cells establish and function in a lymphocyte-deficient host.
Q3: How are splenocytes isolated and purified from donor tissue?
The spleen is dissociated using a cell strainer and plunger to release cells into suspension. Unwanted erythrocytes are lysed using ammonium chloride potassium lysing buffer, and centrifugation separates white blood cells from debris. The resulting purified splenocytes are counted using trypan blue and adjusted to the desired concentration before transfer into recipient mice.
Q4: What is the role of flow cytometry in confirming successful adoptive transfer?
Flow cytometry using fluorescence-activated cell sorting (FACS) confirms transfer success by detecting donor cells in the host spleen. Labeled antibodies against donor markers like CD45.2 distinguish transferred cells from host cells. The technique allows researchers to identify specific lymphocyte populations, such as CD4 T-cells, and verify their presence and distribution in recipient mice.
Q5: How is the cell suspension prepared before intravenous injection into recipient mice?
The cell suspension is centrifuged and resuspended in phosphate buffered saline through two sequential wash steps. The final pellet is resuspended in 200 microliters of phosphate buffered saline. Using a 0.5 milliliter syringe with a 29-gauge needle, 200 microliters of this purified cell suspension is injected intravenously into the retro-orbital blood sinus of the recipient mouse.
Q6: What does the FACS analysis reveal about transferred versus host lymphocytes?
FACS analysis distinguishes CD45.2 positive transferred cells from CD45.1 positive host cells using dot plots. Transferred cells appear only in the transferred mouse sample, not in control mice receiving phosphate buffered saline alone. Further analysis identifies specific transferred lymphocyte subsets, such as CD4 T-cells, demonstrating both successful engraftment and the phenotype of donor cells within the host.
Q7: What compatibility factors must be considered before performing adoptive cell transfer?
Host and donor compatibility is crucial to ensure cell adoption without rejection. In this protocol, CD45.2 donor splenocytes are transferred into CD45.1 Rag gamma-c recipient mice, allowing discrimination between donor and host cells. This genetic distinction enables researchers to track transferred cells and assess their integration, survival, and function within the immunocompromised host environment.