A Simple and Rapid Protocol to Non-enzymatically Dissociate Fresh Human Tissues for the Analysis of Infiltrating Lymphocytes

Summary

This protocol describes the rapid non-enzymatic dissociation of fresh human tissue fragments for qualitative and quantitative assessment of CD45⁺ cells (lymphocytes/leukocytes) present in various normal and malignant human tissues. Additionally, the supernatant obtained from the primary tissue homogenate can be collected and stored for further analysis or experimentation.

Abstract

The ability of malignant cells to evade the immune system, characterized by tumor escape from both innate and adaptive immune responses, is now accepted as an important hallmark of cancer. Our research on breast cancer focuses on the active role that tumor infiltrating lymphocytes play in tumor progression and patient outcome. Toward this goal, we developed a methodology for the rapid isolation of intact lymphoid cells from normal and abnormal tissues in an effort to evaluate them proximate to their native state. Homogenates prepared using a mechanical dissociator show both increased viability and cell recovery while preserving surface receptor expression compared to enzyme-digested tissues. Furthermore, enzymatic digestion of the remaining insoluble material did not recover additional CD45⁺ cells indicating that quantitative and qualitative measurements in the primary homogenate likely genuinely reflect infiltrating subpopulations in the tissue fragment. The lymphoid cells in these homogenates can be easily characterized using immunological (phenotype, proliferation, etc.) or molecular (DNA, RNA and/or protein) approaches. CD45⁺ cells can also be used for subpopulation purification, in vitro expansion or cryopreservation. An additional benefit of this approach is that the primary tissue supernatant from the homogenates can be used to characterize and compare cytokines, chemokines, immunoglobulins and antigens present in normal and malignant tissues. This protocol functions extremely well for human breast tissues and should be applicable to a wide variety of normal and abnormal tissues.

Introduction

The tumor microenvironment is composed of various cell types with numerous studies showing they each play distinct and important roles in tumorigenesis^1,2. These include, but are not limited to, infiltrating immune cells, stromal cells, endothelial cells and tumor cells³. Ex vivo studies of tumor infiltrating lymphocytes (TIL; CD45⁺ cells or leukocytes, which are predominantly lymphocytes in breast tumors) from fresh human tissue samples is made difficult by their low frequency, the small sample sizes often available for research and the potential for loss of viability during extraction. Because immune cells infiltrating tumor....

Protocol

NOTE: All specimens were acquired using a protocol approved by the Medical Ethics Committee of the Institute Jules Bordet with written informed consent obtained from each patient.

1. Preparation of the Tissue Homogenate

1. Dissect resected tissues (malignant and normal tissue resected from the operating room) are in the pathology lab by trained personnel for immediate pickup. Tumor, NANT (taken the furthest distance from the tumor as possible) and normal tissue fragments are routinely processed within 1 - 3 hr of surgical excision in a BSL2 laboratory using standard biosafety procedures for human tissues. A flow chart of the protoc....

Results

Enzymatic digestion of tissue fragments with either commercially available tissue dissociation solutions or various laboratory mixtures of collagenase, DNase and/or hyaluronidase inhibitors, cleave a wide variety of receptors on the surface of cells. Our studies, initially focused on CD4⁺ T cells infiltrating breast tumors, were quickly presented with a major technical problem due to cleavage of surface CD4 receptors using standard enzymatic digestion protocols^4-8. We tested a variety of collagenase.......

Discussion

This study describes an optimized method for the rapid preparation of normal and malignant breast tissue homogenates without enzymatic digestion for subsequent cell sorting, extraction, cryopreservation and/or phenotypic analysis of CD45⁺ subpopulations. The goal of this experimental approach is to produce images of the TIL that closely reflect their in vivo state and compare them to normal tissues with minimal manipulation of the tissues fresh from the operating room. To date, our laboratory has used.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
GentleMacs Dissociator	Miltenyi Biotec	130-093-235	BD Medimachine is somewhat equivalent
Centrifuge 5810 R	Eppendorf		or other standard table top centrifuge
Centrifuge 5417 R	Eppendorf		or other standard microcentrifuge
Esco Class II A2 Biosafety Cabinet	ESCO global		or other standard BSL2 hood
Inverted Microscope	Nikon eclipse TS100		or other microscope compatible for a hemacytometer
Bürker Chamber	Marienfield	640210	or other standard hemacytometer
Navios Flow Cytometer	Beckman Coulter		or other flow cytometer (8-10 color recommended)
GentleMacs C-Tube	Miltenyi Biotec	130-096-344	BD Medimachine uses Filcon
Cell Culture Dish	Sarstedt	72,710	or other non-pyrogenic plasticware
Disposable Scalpel	Swann-Morton	0510	or standard single use sterile scalpel
BD Cell Strainer 40 µm	Becton Dickinson	734-0002	or other non-pyrogenic plasticware
BD Falcon Tube 50 ml	Becton Dickinson	352070	or other non-pyrogenic plasticware
BD Falcon Tube 15 ml	Becton Dickinson	352097	or other non-pyrogenic plasticware
BD FACS Tube 5 ml	Becton Dickinson	352008	or other non-pyrogenic plasticware
Sterile Pasteur Pipette 5 ml	VWR	612-1685	or other non-pyrogenic plasticware
Microfuge Tube 1.5 ml	Eppendorf	7805-00	or other non-pyrogenic plasticware
X-Vivo 20	Lonza	BE04-448Q	serum-free medium recommended
Phosphate buffered saline	Lonza	BE17-516F	standard physiological PBS
Trypan blue	VWR	17942E	or other vital stain
VersaLyse	Beckman Coulter	A09777	for flow cytometry experiments
Fixable viability Dye eFluor 780	eBioscience	65-0865-14	for flow cytometry experiments
anti-CD3 FITC	BD Biosciences	345763	for flow cytometry experiments
anti-CD3 Vio Blue	Miltenyi Biotec	130-094-363	for flow cytometry experiments
anti-CD4 PE	BD Biosciences	345769	for flow cytometry experiments
anti-CD4 APC	Miltenyi Biotec	130-091-232	for flow cytometry experiments
anti-CD8 ECD	Beckman Coulter	737659	for flow cytometry experiments
anti-CD8 PerCP	BD Biosciences	345774	for flow cytometry experiments
anti-CD19 APC-Vio770	Miltenyi Biotec	130-096-643	for flow cytometry experiments
anti-CD45 VioGreen	Miltenyi Biotec	130-096-906	for flow cytometry experiments