Hello and welcome to the Mabtech Forum!
I have myself utilized a "quick" coating procedure of only 4 hours incubation at 37C (i.e inside of an incubator). ELISpot plates had in this case been pre-activated with EtOH and the capture antibody was added at a concentration of 1,5 micrograms/well. After 4h hours, the plates were blocked and cells were added.
When the experiment was done and the plates were developed, IFN-g spots came out looking ok (cells stimulated with a-CD3 and PHA). So it most definitely works doing it like this. However, in the same experiment, I also analyzed IL-2. These spots on the other hand suffered both in quality and numbers compared to the recommended protocol of leaving the capture antibody to coat overnight.
Consequently, changing the coating protocol can lead to a lowered ELISpot sensitivity and will affect different antibody systems to various degrees. Although I did not observe a degradation in the results for IFN-g, this might not have been the case had I looked at a low frequency, antigen-specific response, where both the number and amount of IFN-g secreted theoretically can be much lower from each responding cell in comparison to what is seen for PHA and a-CD3.
In essence, changing the time for coating your plates alters your protocol and may or may not affect the outcome of your ELISpot data. Only you can decide if it is worth it or not.
best,
Christian