Answer:
A) Cytokine are the different type of the proteins, peptides and glycoproteins released by immune system like interleukin, interferon, chemokine and growth factors. These cells affect other cells by various means. These are cell signalling molecule regulates hematopoiesis and immunity. Example: interlukins.
B) Interleukins are a group of the cytokines that mediate cell communication and help in cell differentiation, cell growth and regulating motility. As they are cytokines and play role in cell signalling these proteins are essential in immune response. Interleukins 1 is an example of interleukins.
C) Chemokine are also protein molecules that are cytokines, acts as chemoattractants as they attracts other cells to the site of the infection or injury so they can destroy or kill pathogens or microbes. Example : CCR1
D) Chemoattractants are the cytokines that lead the migration of the immunity cells to the site of infection or injury. Chemokine is an example of chemoattractant.