P110δ inactivation in human T cells does not result in the dichotomy between alloresponses in naive and memory T cells observed in mice, as both subsets are affected in humans while only naive T cells are affected in mice.
An interesting issue that needs further investigation is the assessment of whether the higher percentage of effector memory CD8+ T cells observed in HER2+ patients correlates with the enhanced response against TAA noticed in this population.
This activity in so-called memory cells (as observed in microelectrode recordings of neurons in the cortex of primates during the performance of delay tasks) exhibits a number of different general patterns.
After vaccination, although an increase in memory cells was observed in HIV positive patients, yet HBsAb levels were significantly lower than controls (P < 0.05) indicating a functional defect of memory cells in HIV/AIDS patients.
DOI: http://dx.doi.org/10.7554/eLife.05949.013 More naive and memory cells were observed to bind a single pMHC specificity in old mice compared with adults when using dump tetramer gating (Savage et al., 1999).
Furthermore, despite the dramatic enlargement of the effector T-cell pool, numbers of antigen-specific T cells at the memory phase of the response were comparable between treated and control mice, perhaps due to poor conversion to memory cells as observed when non-physiological numbers of TCR transgenic T cells are analysed 15.
These data are also consistent with impaired memory cell formation observed in the absence of IRF4 after infection with L. moncytogenes.
In addition to prefrontal cortex, memory cells have been observed for example in posterior association cortex including inferotemporal cortex [54] [55], and posterior parietal cortex [56] [57], and their simultaneous presence in multiple cortical areas have been indicated in imaging studies [55], [58] [60].
Since reduction of central memory T cells (Tcm) with a concomitant increase of effector memory cells (Tem) is commonly observed in HIV infection and this unbalance is only partially restored under effective HAART [5], these T cell subsets were evaluated upon immunization with Tat.
In the primary response (mice primed with PBS), the OVA-specific CD8+ IFN-γ+ T cells also produced some IL-2 and TNF-α although much less than observed with memory cells.
