[Immunoglobulin concentration in equine colostrum and blood of newborn foals as well as clinically relevant IgG evaluation methods - An overview]. / Immunglobulinkonzentration im equinen Kolostrum und im Blut neugeborener Fohlen sowie klinisch relevante IgG-Bestimmungsmethoden.

Due to the special structure of the equine placenta, foals depend on an adequate intake of high-quality colostrum post natum in order to ensure the development of passive immunity. The quality of the colostrum is determined, among other things, by the IgG content. This may be evaluated in the colostrum by direct and indirect methods (density and refractive index). The density of the colostrum is measured by a colostrometer and should amount to at least 1060 g/l. Refractometry is suitable for assessing the relative density or refractive index. Good equine colostrum has a Brix value of at least 23 %. The IgG concentration in the blood of the foal may also be determined by direct and indirect methods. The SNAP®-Test is regarded as a direct semi-quantitative measurement method, with values > 800 mg/dl indicating an adequate IgG concentration. Furthermore, the radial immuno-diffusion test, the latex agglutination test, and the immunoturbimetry are direct methods that may be applied. Indirect methods include the zinc sulphate turbidity test, the glutaraldehyde coagulation test, as well as the measurement of total protein, globulin concentration and γ-glutamyl transferase activity.

Effects of feeding different roughage components to sows in gestation on bacteriological and immunological parameters in colostrum and immune response of piglets.

In piglet production, Escherichia coli (E. coli) and the presence of lipopolysaccharides (LPS) were considered as predominant causative agents in the aetiology of important diseases of sows and piglets. The aim of the study was to assess the effects of feeding different roughage sources to sows in gestation on the microbiota and endotoxin concentration in colostrum and on the specific immune response of their piglets. In two trial runs, a total of 144 sows were assigned to one of the six dietary treatments: the Control group receiving a concentrate diet and five groups with a restrictive supply of the control diet in combination with straw (S), hay (H), clover grass silage (GS), maize silage (MS) or Jerusalem artichoke (JA). During lactation no roughage was offered. Colostrum samples were analysed for bacteriological and immunological parameters. Blood samples were taken from two piglets per corresponding litter to examine the concentration of C-reactive protein (CRP) and of specific antibodies to LPS of E. coli (strain J5). Roughage feeding had an effect neither on the total bacterial count nor on the content of E. coli in colostrum of sows. The concentration of LPS in colostrum was reduced in Group MS. The concentration of CRP in the colostrum samples was low and independent of the feeding regime (max. 9.3 µg/ml). However, the administration of roughage components rich in crude fibre (Groups H and S) decreased the level of CRP in colostrum significantly. The analysis of the specific immunoglobulin to LPS of E. coli (strain J5) showed a higher concentration of IgG-anti-LPS in blood serum of piglets from sows of Group JA. The results suggest that the inclusion of selected roughage components may have the potential to affect the immunocompetence of sows and their corresponding piglets.

Dynamic changes of immunoglobulin concentrations in pig colostrum and serum around parturition.

The aim of the study was the determination of IgA, IgM and IgG concentrations in porcine serum and colostrum, in order to evaluate their variations in the perinatal period, as well as to clarify whether there is a correlation between colostrum intake, initial level of immunoglobulins (Ig) in piglet serum and development of their own immunity. The mean IgA, IgM and IgG concentrations in sow serum 10 days before parturition were 1.58, 6.12 and 39.56 mg/ml, respectively. Seven days later only the IgG level was insignificantly lower (34.94 mg/ml, p = 0.55), while concentrations of IgA and IgM increased to 2.25 and 7.25 mg/ml, respectively (p = 0.23 and 0.62, respectively). The mean initial IgG concentration in colostrum at farrowing was 118.5 mg/ml and differed between sows. The average value of IgA in colostrum at birth was 23.8 mg/ml and decreased to 7.85 mg/ml at 6 hours (h) and to 4.59 mg/ml at 24 h after the onset of farrowing. IgM concentration at birth was 12.1 mg/ml and decreased to 4.23 mg/ml at 24 h postpartum. Positive relationships were found between concentrations of IgM and IgA in serum of piglets at 14 and 56 days of life (r = 0.41 and 0.80, respectively, p < or = 0.05) as well as for IgG concentration in the piglets serum at 7 days and 56 days of age (r = 0.48, p < or = 0.05). The above observations suggest that there is a correlation between the level of Ig in piglet serum in the first days of life and improvement of their own immunity.

Transfer of antibodies across the placenta and in breast milk from mothers on intravenous immunoglobulin.

We studied the levels of immunoglobulins in colostrum, milk and sera from two common variable immunodeficiency (CVID) mothers (M1 and M2), and in sera from their newborn infants. During pregnancy they continued intravenous immunoglobulin therapy (IVIG). Antibody levels from maternal and cord blood collected at delivery and colostrum and milk, collected on the 3rd and 7th post-partum days, respectively, were analyzed. Although cord/maternal blood ratios of total immunoglobulins and subclasses, as well as specific antibodies differed between M1 and M2, both showed good placental transfer of anti-protein and anti-polysaccharide antibodies, despite lower cord/maternal blood ratios in M2. Anti-Streptococcus pneumoniae antibody avidity indexes were similar between paired maternal and cord serum. Both mothers' colostrum and milk samples showed only traces of IgA, and IgM and IgG levels in colostrum were within normal range in M1, whereas M2 presented elevated IgG and low IgM levels, when compared with healthy mothers. The study of colostrum and milk activity showed that they strongly inhibited enteropathogenic Escherichia coli adhesion in vitro. CVID patients must be informed about the relevance of regular IVIG administration during pregnancy, not only for their own health but also for their immune immature offspring. Breast-feeding should be encouraged as colostra from these CVID patients strongly inhibited E. coli adhesion to human epithelial cells thus providing immunological protection plus nutritional and psychological benefits for the infant.

Effect of dietary fiber on the lipid metabolism and immune function of aged Sprague-Dawley rats.

Eight-month-old Sprague-Dawley rats were fed on diets containing dietary fiber at the 5% level for 3 weeks to examine the effect on the lipid metabolism and immune function. Among cellulose, guar gum, partially hydrolyzed guar gum (PHGG), glucomannan and highly methoxylated pectin, guar gum induced a significant decrease in the food intake and weight gain, as well as a significant increase in the liver weight. In addition, the epidydimal adipose tissue weight of the rats fed on PHGG was significantly higher than that of the rats fed on cellulose. There was no significant effect on the serum lipid levels, but the serum IgG level of the rats fed on guar gum was significantly lower than that of the rats fed on cellulose. The IgA and IgG productivity in mesenteric lymph node (MLN) lymphocytes was significantly higher in the rats fed on guar gum, glucomannan and pectin than in those fed on cellulose, while the effect on Ig productivity in spleen lymphocytes was not as marked. In addition, only guar gum induced a significant increase of IgM productivity in MLN lymphocytes when compared to the cellulose group. These results suggest that enhancement of the immune function by dietary fiber is mainly expressed in the gut immune system.

Immunoglobulins of camel (Camelus dromedarius) colostrum.

Immunoglobulins G, M and A were identified in dromedary camel colostra by acid precipitation, gel filtration and fast-protein liquid chromatography (ion exchange). Heavy and light chains were identified by polyacrylamide gel electrophoresis and Western blotting. IgG subclasses (IgG1, IgG2 and IgG3) were isolated by DEAE ion-exchange chromatography and shown to have different electrophoretic mobilities. Cross-reactivity of camel IgA with IgA of other species was determined by enzyme-linked immunosorbent assay (ELISA). Most of the immunoglobulin content was IgG, but a molecule identifiable as IgA was detected and purified. It would appear that in the camel, as in cattle, IgG is the major secretory immunoglobulin of colostrum.

Determination of the molecular structure of the human free secretory component.

Here, we present the experimental data, leading to determination of the primary structure, the linkage of the carbohydrates and the arrangements of the disulfide bonds of the human free secretory component. Methods of protein chemistry were used. The protein can be divided into five homology regions and is a member of the immunoglobulin superfamily.

Characterization and measurement of immunoglobulins in the grey seal (Halichoerus grypus).

Immunoglobulin concentrations were measured in the serum and colostrum of adult and pup Grey seals from North Rona in the outer Hebrides and the Isle of May in the Firth of Forth. IgG was shown to be the main immunoglobulin and two subclasses were identified. Serum immunoglobulin content was low in the week-old pups and increased up to 5 weeks, although it remained substantially lower than in the adults. Colostral immunoglobulins were high and cannot explain the low values in the pup serum. It is considered that the increased opportunistic infections seen in Grey seal pups may be related to this low immunoglobulin status.

Immunoglobulin production and transport by the mammary gland.

In origin immunoglobulins in mammary secretions are both humoral, arising from the blood stream, and local, arising from production by plasmacytes in the mammary gland. The relative importance of each of these sources varies between species. In some species (human, rabbit, etc.), the transfer of maternal immunoglobulins to the blood stream of the neonate occurs in utero across the placenta or yolk sac membrane. In other species, including ruminants, transfer of maternal immunoglobulins to the neonate occurs exclusively via the colostrum. Both in utero and colostral routes of transfer are operative in other species. The concentration and class of immunoglobulins in the colostrum and milk of a species reflect the route and origin of the immunoglobulins. Immunoglobulins transferred in quantity in utero or via the colostrum are mainly of the IgG class. Immunoglobulins locally produced by plasmacytes located adjacent to the secretory epithelium and in the mammary secretions are largely of the IgA and IgM classes. The bovine transfers large amounts of IgG immunoglobulins, and IgG1 in particular, from the blood stream across the mammary barrier into colostrum (and milk) by a specific transport mechanism. Bovine colostrum and milk also contain much smaller amounts of locally produced IgA and IgM.

Isolation of porcine immunoglobulins and determination of the immunoglobulin classes of transmissible gastroenteritis viral antibodies.

The porcine immunoglobulins M (IgM), A (IgA), and G (IgG) were isolated and purified and some of the properties of the porcine milk IgA were examined. Monospecific antisera which were prepared against these immunoglobulins in rabbits were then used to absorb a particular class of immunoglobulin from sow serum, colostrum, and milk in an attempt to identify the immunoglobulin classes of neutralizing antibodies to the porcine enteric virus, transmissible gastroenteritis (TGE). The results of these absorption studies suggest that in colostrum and milk from sows experimentally (orally) or naturally infected with live virulent TGE virus, IgA is the predominant immunoglobulin class of TGE antibodies. Both IgA and IgG TGE antibodies appeared to be present in the serum from these sows, but with IgG TGE antibodies predominating. In contrast, in the serum, colostrum and milk from sows vaccinated intramuscularly or intramammarily with live attenuated TGE virus, the TGE antibody activity was associated mainly with the IgG class of immunoglobulins. These results provide additional data indicating that the route of infection or vaccination markedly influences the immunoglobulin class of antibodies in colostrum and milk. Secondly, IgA antibodies in mammary secretions are probably essential for providing optimal passive immunity of nursing pigs against infection with TGE virus.