Good Morning Michael, 

Thank you for contacting the U of M Extension Service. 

Here is a link from the U of M Extension Yard and Garden website about pruning and trellising tomatoes: https://extension.umn.edu/yard-and-garden-news/three-ways-trellis-tomatoes 

This information states:

No matter which method you use, make sure to prune your plants throughout the early summer. Removing the bottom leaves helps to prevent pathogens in the soil from splashing up onto the leaves. Removing suckers (the little leafy shoots above each stem), helps the plant to direct its energy into growing strong leaves and stems that can support more fruit.

I would prune off the plants bottom leaves and the suckers. You should sterilize your pruning tools between plants so you are not spreading pathogens.  Have you added too much nitrogen to the soil? This would encourage more leaves. 

Here is another link about growing tomatoes: https://extension.umn.edu/vegetables/growing-tomatoes

Good Luck!