Immunoglobulin fraction and process therefor

#The invention relates to the production of compositions containing IgA for use as a food additive. More specifically, it relates to a process to prepare an IgA-enriched milk product extract composition and to such compositions.

#The present invention is to be understood in light of what has previously been done in the field. However, the following discussion is not an acknowledgment or admission that any of the material referred to was published, used or part of the common general knowledge in Australia as at the priority date of the application.

#Immunoglobulin A (IgA) is the dominant immunoglobulin in human secretions, including breast milk and provides the body with protection against pathogens, binding to disease-causing viruses, bacteria, fungi and their toxins. IgA provides infants essential protection against the aforementioned pathogens. IgA antibodies are effective when taken orally because they are resistant to degradation by enzymes in the gut, thus making them ideal as nutraceuticals or food supplements. IgA may be combined with probiotics to inhibit or reduce adverse effects due to pathogens. Applications include use of IgA as a nutraceutical ingredient to target pathogens which cause infections of human mucosal surfaces such as in the nose, eyes, ears, lungs, breast and vagina. Moreover, IgA-containing products are suitable for gut and oral health applications. Due to the low levels of IgA normally present in cows' milk, the established method to increase the yield of IgA on a commercial scale is by immunisation regimes to boost the levels in the milk. Typically, cow's milk contains IgA and IgG in a ratio of approximately 1:8.

#FIG. 1—IgA:IgG in various animal products analysed by ELISA.

#FIGS. 2A-2C—Effect of Salt concentration and flow rate of elution on IgA elution.

#FIGS. 3A-3E—Effect of milk product volume contacted with cation exchange resin.

#The following is a detailed description of the preparation of an IgA-enriched fraction of the present invention.

#Suitable sources of IgA may include milk products such as whole milk, skim milk, whey or colostrum from a mammal such as man, cow, sheep, goat, sow or the like. In contacting the milk product with the cation exchange resin to allow the IgA to adsorb, the pH of the milk product is preferably about 6.5 although it is not necessary to adjust the pH of the milk product for the present invention.

#The flow rates used to contact the milk product with the cation exchange resin can be varied over a wide range, such as from 6-90 liters per liter resin per hour (linear flow 60-900 cm per h), preferably, 6-70 liters per liter resin per hour (linear flow 60-700 cm per h), more preferably about 6-40 liters per liter resin per hour (linear flow 60-400 cm per h). The lower limit is determined by cost-effectiveness for an industrial process, whereby at very low flow rates the cost to run the process exceeds the return. High flow rates are suitable for IgA purification provided the total amount of milk product contacted with the resin is limited.