A method of quantitative assessment of cytokine gene mRNA expression levels using real-time PCR in homogenous low cell number populations

We propose a method of quantitative functional activity assessment in cells isolated via sorting on a flow cytometer. We show that cell populations vary in the mRNA expression of cytokine genes immediately after isolation and sorting, while the maintenance of homogenous populations in culture without stimulation results in an increase in these gene mRNA expression. Using the original system, it is now possible to detect mRNA cytokine genes with high sensitivity, starting from 90 cells per specimen. This approach permits genetic and immunogenetic analysis of gene expression with the goal of determining their functions in the in vitro studies.