Final answer:
Humoral antibody responses involve the production of antibodies by plasma cells as part of the immune response. Transformation into plasma cells occurs when B cells are activated and secrete immune antibodies. Hyperacute rejection is a separate event in organ transplantation.
Step-by-step explanation:
Humoral antibody responses refer to the production of antibodies by plasma cells as part of the immune response. When B cells are activated, they differentiate into plasma cells, which are responsible for secreting immune antibodies. These antibodies circulate in the bloodstream and can neutralize pathogens, mark them for destruction, or activate other components of the immune system. However, hyperacute rejection is a different phenomenon that occurs in organ transplantation and is unrelated to humoral antibody responses.