Association of LFA-1 to
ICAM-1 is concomitant with B cell activation. The FLIPR
assay measures the flux of intracellular calcium, a response
that is definitely upstream of LFA-1/ICAM-1 adhesion.
The objective of this report was to compare the scope
and worth of each engineering like a screening platform.
Ramos cells handled with anti-IgM elicited a robust Ca
response from the FLIPR assay. It really is noteworthy that chronic
anti-IgM therapy (on the order of 24�C48 h) continues to be
proven to elicit cell death.
Importantly, acute application
of anti-IgM in these research (2 min application) elicited a
calcium response that peaked 80�C100 s submit application fol-
lowed by decay on the signal, a kinetic profile that is not
consistent with cell death.
In contrast to the FLIPR assay,
Ramos cells didn't elicit an EPIC response, precluding
their use in EPIC research. The absence of an EPIC response
in Ramos cells is very likely attributed to your lack of LFA-1
expression within this cell line.
Even so, RL cells elicited responses in the two the FLIPR and EPIC platforms.
Both the EPIC and FLIPR platforms had been validated
utilizing a panel of instrument compounds that have been reported to
inhibit critical signaling proteins and pathways involved in B
cell activation and/or displayed Pazopanib efficacy in models of
immune and inflammatory disorder. Generally, the rank
purchase of potency for your instrument compounds was very similar for
each platforms. On the other hand, there have been obvious rightward
shifts in potencies for a lot of the compounds that were cell
The potency with the tool compounds was
consistent inside of the RL cellular background, irrespective
of assay platform. In contrast, the pharmacology usually
seems to get rightward shifted when comparing Ramos
cells versus RL cells during the FLIPR platform. One can specu-
late the potency of the compound will depend on the cel-
lular repertoire and possible polypharmacology inside of a
given cell line. Indeed, the data emphasize the importance
of totally evaluating the cell line of preference.
With respect to potency, dasatinib and RN-486 have been the
only compact molecules that displayed submicromolar poten-
cies among all three cell-based assays. The variety I inhibitor,
R406, targets SYK and also to a lesser extent BTK. R406 did not
show appreciable inhibition of anti-IgM-mediated B cell
activation as measured from the FLIPR and EPIC assays.
R406 has become reported to block SYK-dependent BCR-
mediated activation of B lymphocytes BI2536 clinical and inhibit paw
irritation in antibody-induced arthritis mouse models.
It is actually worth noting the cell-based assay employed primary
human B cells stimulated with anti-IgM and measured
CD69 upregulation. On this situation, cells were taken care of with
inhibitor for 60 min followed by continual treatment (6 h) with anti-IgM.
In the FLIPR-based assay, cells have been
treated with R406 for thirty min followed by addition of anti-
IgM (acute remedy), and immediate modifications in calcium
flux had been recorded.