A proline-rich polypeptide complex (PRP), subsequently called Colostrinin (CLN), was first isolated from ovine colostrum, was shown to possess immunoregulatory properties, including effects on the maturation and differentiation of murine thymocytes and humoral and cellular immune responses, both in vivo and in vitro. PRP seems to restore balance in cellular immune functions and is not species specific. PRP is a complex of peptides of molecular masses ranging from 500 to 3000 Da. The polypeptide contains 25% proline and 40% hydrophobic amino acids. PRP shows a regulatory activity in cytokine (IFN, TNF-alpha, IL-6, IL-10) induction and possesses the ability to inhibit the overproduction of oxygen reactive species and nitric oxide. Besides its immunoregulatory activity, PRP also showed psychotropic properties, improving cognitive activity and behavior of old rats, humans, and chickens. The properties of PRP prompted the authors to propose the complex for the treatment neurodegenerative disorders. Beneficial effects of PRP/Colostrinin were shown for the first time in double-blind placebo-controlled trials and long-term open-label studies. The results were confirmed in multicenter clinical trials. A very important property of PRP/Colostrinin is the prevention of Abeta aggregation and the disruption of already existing aggregates. The same properties were expressed by one of PRP’s components, a nonapeptide (NP). Moreover, PRP modulates neurite outgrowth, suppresses uncontrolled activation of cells, reduces 4-HNE-mediated cellular damage, and modulates expression in cellular redox regulation, cell proliferation, and differentiation. Its biological response modifying activity can play an important role in its use in the treatment of Alzheimer’s disease.

OBJECTIVE: It has previously been demonstrated that oral administration of ovine Colostrinin (CLN), a proline-rich polypeptide isolated from ovine colostrum, can effectively treat Alzheimer’s disease patients. This study aims to determine whether CLN has effects on the aggregation and toxicity of synthetic beta-amyloid (Abeta), implicated as a causative agent of AD. DESIGN AND MEASUREMENTS: Using cell assays, we examined if pre-treatment of neuronal cells with CLN confers protection. RESULTS: The data from cytotoxicity assays (using MTT and LDH) demonstrated that pre-treatment of human neuronal SHSY-5Y cells with 5 microg/ml CLN, for 24 hours, confers neuroprotection against Abeta-induced neurotoxicity. Twenty-four hour pre-treatment with 5 microg/ml CLN was also shown to reduce Abeta 1-40-induced apoptosis in human neuronal cells as determined via qualitative and quantitative apoptosis assays. CONCLUSION: The neuroprotection conferred with CLN pre-treatment was reduced with the Fas ligand (FasL) binding antibody Nok1, suggesting that the effects of CLN may involve a Fas:soluble FasL interaction. These findings indicate that CLN could possibly play a role in the prevention of AD pathogenesis, though the inhibition of Fas-mediated apoptosis.

A proline-rich polypeptide complex (PRP) isolated from ovine colostrum. Modulation of H2O2 and cytokine induction in human leukocytes

Agnieszka Zablocka, Maria Janusz, , Józefa Macalaa and Józef Lisowskia

Abstract

A proline-rich polypeptide complex (PRP) has immunoregulatory properties and also shows beneficial effects in Alzheimer’s disease (AD). It is known that the unregulated activation of microglial cells in AD may result in chronic inflammatory response. There is a link between the activation of immune cells on the periphery and in the central nervous system (CNS). Therefore, we studied the effect of the PRP on human peripheral blood mononuclear cells (PBMCs) stimulated by LPS with PHA (LP) or PMA as proinflammatory activators. PRP and its nonapeptide fragment (NP) inhibited by 40‚Äì60% production of H2O2 induced by PMA. The peptides also inhibited activity of superoxide dismutase. Both peptide preparations showed differential effects on the secretion of cytokines. NP induced TNF-Œ± only while PRP induced IL-6, IL-10 and TNF-Œ±. On the other hand, the release of TNF-Œ± and IL-10 induced by LP in PBMCs was inhibited by PRP while NP inhibited the release of IFN-Œ≥ and IL-10. The results obtained showed that PRP may affect not only adaptive immunity but also innate immunity and thus may regulate secretions of mediators of inflammation. The regulatory effect of the PRP on the innate immunity may shed some light on understanding the beneficial effects of this polypeptide complex in AD patients.