Are antigens and t-cells related?

T cells use antigens: Antigens are parts of large molecules, usually proteins but occasionally carbohydrates, that your immune system samples to see if they are part of your body or foreign. If foreign your immune system will try to cleanse your body of this stuff. Dendritic cells process and present antigens to t cells that in turn direct the body's immune response against the antigen.

Yes and no: T cells are a particular type of cell of the specific immune system. T cells can be activated by specific antigens through their t cell receptors. An antigen is a particle with that is recognized by the immune system (b cells, antibodies, t cells, etc.).