Could you please elaborate what are you trying to do and with what tissue or material?
As there are many methods you can use for your study you can use ELISA or WB or qPCR to evaluate the expression. With sections you can do immunoflorecence or immuhystochemistry staining. I will be happy to help but you need to give me more information of what are you trying to do. Is it an experimental endpoint where you sacrifice the animals or you want a constant monitoring of this proteins in live animals? The exact choise of methods depends on your design, goals, skills and available equipment.
I completely agree with Anton. Western blot, ELISA and/or qPCR are great methods for quantifying and/or evaluating expression, but that depends on what you want to measure (protein vs genomic changes). If you can provide us more details on what your research project is hoping to demonstrate (aka what questions are you hoping to answer), this will help you narrow down the type of appropriate experiments to perform.
Not quite sure what you mean by first principle but,
ELISA would be best for measuring TNFalpha or CRP that has been released from cells into either the blood stream [for animal studies involving the serum] or cell culture medium [for cell culture studies]. NFkB would best be measured by western blot, but often we are interested in NFkB nuclear localisation, which is indicative of its activity [often followed by TNF and/or CRP production] and this can be measured using an electromobility shift assay [EMSA].
ELISA and Western blotting can be used to analyse TNF alpha. For NF kappa b western blotting can be done, if you want to study nuclear localization then you can use nuclear cytosolic fractionation also.