Biodiversity of natural resources has served not only for the primary human needs but also for health care, since time immemorial.
As a result of his research, Maslow developed a theory of motivation based on a hierarchy of five primary human needs, each level of which must be satisfied before the next level is fully operational: Physiological needs.
Noteworthy is the fact that primary human fibroblasts need a 2 fold higher dosage for reaching their LD50 value of 42.7 µM (Fig. 1(d)).
Although both methods are xeno-free, they still need primary human tissues.
When isolating more cells than are immediately needed, primary human hepatocytes can be provided to other laboratories, either by shipping plated cells or by sending them in cold-stored cell suspensions.
Phenotypic assays measuring HBV infectivity are less advanced but several surrogate systems obviating the need for primary human hepatocyte cultures are being established.
Evidence that hNPCs continue to use developmental mechanisms after many weeks of in vitro culture would demonstrate that hNPCs provide a relevant in vitro model for exploring aspects of human neurogenesis that minimizes the need for primary human fetal tissue.
The optimised protocol described here is easy to implement and should facilitate the production of high-titre lentivirus with superior transduction efficiency in primary human T cells without the need for further purification methods.
Armed with knowledge and followed by positive presumptions, could we move forward with the understanding that once we meet the primary level of human needs, we are to assist in the development of the secondary needs and perhaps into full illumination and empowerment?
This 3-cell neurogenic scheme echoes observations in rodents in vivo and in human fetal slice cultures in vitro, providing evidence that hNPCs represent a renewable and robust in vitro assay system to explore mechanisms of human neurogenesis without the continual need for fresh primary human fetal tissue.
