The humoral responce is a process of the immune system that includes

foreign cells.

Explanation:

Humoral and Cell-Mediated Immune Responses The immune system distinguishes two groups of foreign substances. One group consists of antigens that are freely circulating in the body. These include molecules, viruses, and foreign cells.

Explanation:

Humoral immunity is immunity from serum antibodies produced by plasma cells. More specifically, someone who has never been exposed to a specific disease can gain humoral immunity through administration of antibodies from someone who has been exposed, and survived the same disease.

your answer is "the 1950's"