Lnterleukin-8 and Related Chemotactic Cytokines—CXC and CC Chemokines

Abstract

This chapter focuses on interleukin-8 (IL-8) and related chemotactic cytokines—namely, CXC and CC chemokines. IL-8 is the best known member of a new class of cytokines that are widely studied because of their ability to attract and activate leukocytes, and their potential role as mediators of inflammation. IL-8 was originally isolated from the culture supernatants of stimulated human blood monocytes and was identified as a protein of 72 amino acids with a molecular weight of 8383. The three-dimensional structure of IL-8 has been studied by nuclear magnetic resonance spectroscopy and X-ray crystallography. In concentrated solution, and on crystallization, IL-8 is present as a dimer. The first CC chemokine was identified after cloning by differential hybridization from human tonsillar lymphocytes and was termed LD78. The CC and CXC chemokines are similar in size and have an overall structure that is characterized by the two intrachain disulfide bonds, short N-terminal and long C-terminal sequences. It discusses the role of chemokines in pathology with skin inflammation because psoriasis was the first disease to be linked to overproduction of IL-8. Several independent studies document the occurrence of high levels of IL-8 in the synovial fluid of inflamed joints of patients with different forms of rheumatic diseases, osteoarthritis, and gout.