Recombinant Human CRISP-3 Protein, CF

CRISP-3 is one of three CRISPs (cysteine-rich secretory proteins) found in mammalian exocrine secretions and granulocytes that may play a role in innate immunity (1-3). CRISPs and several snake, insect, and lizard venom proteins are characterized by 16 invariant cysteine residues (4). Structurally, they consist of an N-terminal SCP domain, a hinge region, and a cysteine-rich domain (5). CRISP-3 is produced by salivary, pancreas, prostate, and lacrimal glands, as well as spermatozoa and mature spermatids (2, 6, 7). In mouse, however, CRISP-3 has not been detected in the male genital tract (8, 9). CRISP-3 is up-regulated in epithelial prostate cancer and chronic pancreatitis (10, 11). It is present as 30 kDa and 28 kDa species, corresponding to glycosylated and nonglycosylated forms (1, 3, 7, 10, 12). In serum and seminal fluid, CRISP-3 forms high affinity noncovalent complexes with the more abundant alpha 1B-glycoprotein and beta -microseminoprotein/PSP94, respectively (12, 13). Binding is mediated by the SCP domain of CRISP-3 and is independent of glycosylation (12). CRISP-3 is also expressed in pre-B cells but not in T cells or monocytes (14, 15). CRISP-3 is released from neutrophil and eosinophil granules following cell stimulation (1, 15). Mature human CRISP-3 shares 48% and 65% amino acid (aa) sequence identity with mouse and equine CRISP-3, respectively. It shares 44% and 72% aa sequence identity with human CRISP-1 and -2, respectively.