Are modifications required for mRNA transfection?

I am planning an electroporation experiment in primary human T cells using mRNA that can efficiently be translated into a membrane-bound transporter of interest. 

Question:  For this particular experiment (mRNA transfection), are there any specific biochemical modifications that the mRNA should have?

Answer:   No, no special modification is required for this application. However, incorporating 5-Methyl CTP and pseudo-UTP modifications into mRNA may reduce cellular immune-response to transfected mRNA.