Table 1.
Enrichment methods used for fish germline stem cells.
| Method | Principle | Advantage | Disadvantage | Enrichment of Fish GSCs |
|---|---|---|---|---|
| PDGC | Fractionating cells by their density with centrifugation | Simple procedure No need for special materials, techniques, and equipment |
Low purity | The most frequently used method 60–83.6% purity [39,71,72] |
| DP | Positive or negative selection based on adherence of cells by in vitro culture | Simple procedure No need for special materials, techniques, and equipment |
Low purity Relatively long procedure Potential risks of spontaneous differentiation during in vitro culture |
Frequently used >90% purity by serial DPs [73,75] No available commercial molecules for positive selection |
| CE | Aligning and eluting cells by their physical characteristics with centrifugation | High purity expected Not requiring TGs or ABs |
Requiring special sorting conditions and equipment | >90% purity by combining with PDGC [23] |
| FACS | Isolation of cells based on light-scattering properties | High purity expected Flexible sorting condition by customizing gates based on size, granularity, and fluorescent intensity of cells |
Requiring special skills and equipment Requiring specific ABs against the surface protein of target cells, TGs carrying germ cells expressing FPs, or other specific sorting conditions Not suitable for large scales |
Up to 100% purity of PGCs labeled with mRNA-nanos3 3′ UTR encoded FP [17] 93.2–99% purity with TGs [18,19,85] 70.7–80.9% purity using ABs [20,45,86] 75.6–94.9% purity without using TGs or ABs [19,87] Limitation of using TG fish for commercial application No available commercial fish ABs |
| MACS | Affinity based cell sorting with magnetic particles-conjugated ABs against cell surface proteins | High purity expected No need for special techniques or equipment Simpler than FACS Applicable to large scales |
Requiring specific ABs against the surface protein of target cells | 54.8–81.7% purity [62] No available commercial fish ABs |
AB: antibody, CE: centrifugal elutriation, DP: differential plating, FACS: fluorescence-activated cell sorting, FP: fluorescence protein, GSC: germline stem cell, MACS: magnetic-activated cell sorting, PDGC: Percoll density gradient centrifugation, PGC: primordial germ cell, TG: transgenic.