Purification of the human immunoglobulins IgG and IgM

• Grant number: 16/22474-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2017
• End date: May 31, 2018
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Elisabeth Cheng
• Grantee: Camila Oliveira Carneiro
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

The need of plasma therapeutic proteins continues to increase in global level, even with the development of a number of recombinant products. IgG is currently the most important hemoderivative and is responsible for 50% of the world market. The interest in the plasma derived IgM is increasing due to the increasing of results suggesting that this protein can present anti-inflammatory and immuno-modulatory activities and can be a tumoral marker. In order to explore all its potential, it is necessary to develop processes to obtain large amounts of IgM, making it available, at low cost, for the realization of clinical trials.There is a new process for the purification of hemoderivatives under development in our laboratory, in which the coagulation factors are separated in the first step, without the need to separate the cryoprecipitate. The second chromatography uses as the starting material the fraction of the proteins that are not adsorbed in the first column. After a systematic study varying pH and salt concentration it was possible to separate 3 fractions, one containing albumin, one containing IgG and a third containing IgM. The main contribution of this study was to show that the separation of the IgM fraction was compatible with the purification of the most important hemoderivatives, that is, the coagulation factors in the first step and IgG and albumin in the second step. Furthermore, albumin and IgG were obtained in each concentrate with a purities higher than 90%. In this project we intend to continue this study, since it is not possible to obtain IgG with the required purity with a single purification step. With the IgG fraction, we intend to improve the purity of this protein to a minimum of 95%, which is the required purity for endovenous application. For that, we will verify the possibility of using a second anion exchange column. This is a new strategy, since in the existing processes the anion exchange column is followed by a cation exchange column or vice-versa. For comparison, we will perform a purification using a cation exchange column.For the IgM enriched fraction, we intend to separate IgA from IgM, since side effects in IgG commercial products have been attributed to the presence of IgA. It will be tested a cation exchange column and a gel filtration column. There is no legislation regarding the required IgM purity for commercial preparations, therefore we will focus in the separation of a contaminant protein.