Modulation of [Ca2+]i in freshly isolated mouse lymphocytes with in vivo priming

Studied at the level of the individual cell, the pattern of [Ca2+]i mobilization of in vivo sensitized mouse lymphocytes by T-dependent antigen (KLH), challenged in vitro by Con A, PHA or anti-CD3epsilon mAb in different periods after immunization, was as follows. In the entire DLN lymphocyte population and in tested T cell subsets from immunized mice, baseline [Ca2+]i was significantly increased and cells were able to respond additionally to stimuli. In KLH-primed DLN lymphocytes, calcium mobilization in response to membrane receptor-dependent stimuli (anti-CD3epsilon, PHA, and ConA) was increased. Enhancement of Ca2+ mobilization is parallel with changed immunophenotype. These findings suggested that: (a) [Ca2+]i mobilization could correlate with lymphocyte behaviour during immunization and that mobilization clearly depended on kinetics of immune reaction; (b) the higher level of activity among sensitized lymphocytes was due to the increased number of specific B-cells (Ia(k+)) and gammadeltaTCR+ cells; (c) the quantitative measurement of [Ca2+]i could be an important biochemical parameter to study cellular reaction to a specific antigen.