The antigen should be sent at the conditions that the customer feel that  the antigen will remain most stable. Usually, most proteins should be shipped on dry ice. Peptides and conjugated  peptides in solution can also be sent on dry ice. Most lyophilized  antigens and antigens bound to nitrocellulose membranes are stable at room temperature and can be sent at room temperature. Gel slices should be sent on ice packs (blue ice).