IMMUNOGLOBULINS:

The immunoglobulins are a complex group of proteins that make a significant contribution to the protein content as well as exerting an important immunological function, especially in colostrum. The structure and general function of bovine immunoglobulins has been reviewed by Larson (1992) and Buttler ( 1973,1983).

The immunoglobulins found in bovine whey and colostral whey include:

IgA and secretory IgA

IgG_1, IgG₂ and IgG fragments

IgM

IgE

J-chain or component

free secretory component

The nomenclature of the immunoglobulins is based on their immunological cross reaction with reference proteins, preferably of human origin and proposed by the World Health Organisation (Buttler, etal., 1971).

All the immunoglobulins are glycoproteins that are monomers or polymers of made up of two light chains (~20,000 Dal) and two heavy chains (~50,000 - 70,000 Dal) linked together with sulphide bonds (Buttler, 1974, Lascelles, 1979). In the molecules of a class or subclass, the two have chains are identical -- with a constant and a variable region. The light chains are also identical with constant and variable regions. The variable N-terminal regions of both the heavy and light chains provide the antigen binding sites, whereas, the complement fixation, membrane transport, species specific and class specific antigenic determinants are related to the constant region of the heavy chains (Buttler, 1974, Lascessels, 1979).

The variable carbohydrate moiety bound to the heavy chain is considered to be important in the specificity of the Igs.

Biological Activity:

Immunoglobulins are well recognized to provide disease protection to new-born through passive immunity and there is evidence that the immunoglobulins may also have a role in disease control in adults. Relatively few studies have been made concerning the incidence and specificity of immunoglobulins in commercial milk supplies. Chan, et.al. (1994) reported on the IgG concentration of 254 raw milk samples collected from the Province of British Columbia over a two year period. The IgG values varies from 0.03 to 0.71 mg/ml, with media values of about ~.25mg/ml. There were significant values in the levels of IgG among the milks from the 14 different dairies and the IgG values from the same dairy varied from one year to the next. These findings suggest that milk from a large number of cows, as would be found in the milk from commercial dairies, will have activity against a wide range of different bacteria, although the level of activity may vary from year to year and with geographical location.

However, using ELISA testing, all of the milks showed measurable antibody binding activity against the lipopolysaccharide (LPS) fraction of 5 different bacteria (Shigella flexneri 1A, Escherichia coli 0111:B4, Escherichia coli 0128:B12; Salmonella typhonerium and Salmonella enteritidis. Immunization of cows with the 5 organisms gave a significant increase in the LPS activity only for the S. enteritidis in relation to any of the commercial raw milk samples. The activities for the other four organisms were about the same.

The number of specific immunoglobulins in the whey from commercial milk supplies is not known, but will reflect the exposure of the cows to antigens in their natural environment. Where a given milk supply represents milks from thousands of individual cows, it is to be expected that there will be a wide range of different immunoglobulins present -- the type of levels of which would be expected to vary widely. It is known that whey protein concentrates, treated to avoid denaturation, from mixed milk supplies generally contain sufficient antibody to E. coli K-99 to meet the requirements of the USDA to serve as a colostrum supplement.

Hyper-immune milk/whey:

Immunization of cows with specific antibodies has been practiced for a number of years on a limited basis, with the resulting milk being characterised as “hyper-immune milk”. Some ‘immune milk has been produced and marketed in Asian countries (Rider, S., 1992; Hilpert, 1980). However, the extent in the increase in specific activity of the antibodies appears to be dependend up the specific organism and agent used for vaccination. Chan, etal. (1994) found increased ELISA activity for only one of five bacterial antigen in immunized cows in comparison to the levels of activity in milk from commercial dairies. Tomita, et.al. (1995) vaccinated cows with a lipopolysaccharide-protein conjugate derive from E. coli J5. Immunization did enhance serum antibody titer to J5, but did not enhance whey IgG titers.

Ormrod and Miller (1991) reported the isolation of a low molecular weight fraction of the milk of dairy cows immunized with a multivariate bacterial vaccine which was shown to have anti-inflammatory activity in the rat hind-paw oedema assay.

Kobayashi, et.al (1991) and Ishida, et al (1992) showed that ‘immune’ milk, obtained from cows immunized with a mix bacteria flora, showed a higher survival rate for mice given lethal doses of irradiation as compared to control mice not receiving the ‘immune’ milk. Concentration of IgA in a cell culture derived from Peyer’s patches, mesenteric lymph node and spleen was higher from mice given the ‘immune’ milk than for the control mice.

Several studies have suggested that feeding immune milk increases antibodies against the immunizing bacteria and may reduce disease (Murosaki, etal. (1991); Chernokhvostova, et. al, 1990; Boedeker, etal., 1987). In one study reducing the level of free energy intake by 60% appeared to eliminated the differences between B/W mice fed immune and control skim milk.

Whey Biological references up to 1998