Aging of innate immunity: functional comparisons of NK/LAK cells obtained from bulk cultures of young and aged mouse spleen cells in high concentrations of interleukin-2

The technique of bulk cultivation of aged mouse spleen cells in high concentration of IL-2 was employed to obtain NK/LAK cells in sufficient number and enrichment for studies on the effects of aging on their functions. The yield and enrichment were equivalent to that of young mouse spleen cells. The aged and young mouse NK/LAK cells were equivalent also in their functional competence to proliferate, kill target cells and produce IFNγ; i.e. they did not display age-associated defects typical of freshly-isolated NK/LAK cells. In two respects, however, the NK/LAK cells derived from aged mouse spleen were altered: (a) in the efficiency of nuclear translocation of transcription factors STAT 5A and 5B, and (b) in the deficiency in production of mRNA transcripts representing several chemokines. We recommend caution in the use of bulk cultivation in IL-2 to obtain NK/LAK cells for studies on aging. However, it does appear from this study that aging may severely affect chemokine production, at least in the case of NK/LAK cells.