Study For The Absorbing Rules Of Natural Passive Antibody (IgG) In Neogenesis Cow

The placenta of ruminant is phoroplast trophonema pattern,so the maternal antibody can not transport to the foetus.The young stocks of this kind animal obtain natural passive immunity only by suck colostrums after postnatal time.The main process includes the follows:cow selectively transport and enrich the suitable antibodies which accommodate the intestinal environment to the colostrum,then secrete the colostrums which contain a lot of Ig.the calf suck the colosrum and immunoglobulin enter into blood circulation after intestinal non-specificity absorption of immunoglobulin.This immunoglobulin prevents the attack of causative organism to newborn animal.The method which decrease infection and prevent disease by milk is called Lactogenic immunity.Immunoglobulin in the milk is occupy 60%in lactalbumin,and 80%of this immunoglobulin is IgG,it is mainstay to anti-infection immunity and main antibody for serology researching.Contents of serum IgG is index to information of calf passive antibody transporting after sucking colostrums in oversea reports and internal reports.This research detects the change rules of IgG contents in colostrums and calf serum with ELISA,and hope to offer study method and reference for passive immunity researching.In this study,IgG is extracted from ox blood with saturated ammonium sulfate,then obtain IgG and IgM from eribble production with sephodex-G200 gel chromatography,then purify ox IgG with cellulose DEAE-52.The product is identified to be IgG with SDS-PAGE electrophoresis.Rabbit is immunized to prepare rabbit-anti-ox antibody,horse radish peroxidas label the antibody and got IgG enzyme labeled antibody.Mus musculus albus is immunized to get mice-anti-ox coating antibody at the same time.They are established that double sandwich ELISA to detect ox colostrums IgG and calf serum IgG respectively.Operating sequence of ELISA as follows:mice-anti-cow IgG is dilute to 30μg/mL the best suitable coating density with coating buffer,wells of a microtitration enzyme immunoassay plate were coated with 100ul,set up negative well,positive well,antibody control well,enzyme labeled antibody control well and substrate control well,and incubated 3h at 37℃,throw the coating buffer awaa.Wells were rinsed by flooding them 3 times(3 minutes each) with a wash solution containing 0.15M NaCl and 0.05%Tween-20.Test cow's milk was diluted 1:4 or test calf serum was diluted 1:100 in ELISA buffer(0.15M NaCl,0.01M PB,0.05%Tween-20),and 100μl was applied to each well.Plate were incubated for 1.5 hours at 37℃and rinsed 3 times. Horseradish peroxidase-conjugated rabbit anti-cow IgA antibody was diluted 1:400 in ELISA buffer(0.15M NaCl,0.01M PB,0.1%bovine serum albumin,and 0.05%Tween-20 ),and 100ul was added to each well.The plate were incubated for 60 minutes and rinsed as before,100μl substrate containing OPD-H₂O₂ was added to each well.Plate were laid in 37℃protect from light for 20 minutes.The reaction were termination with a drip of stop buffer(2M H2SO4) each well.Plate were read by enzyme linked immunosorbent assay instrument.20 samples of cow milk and new born calf serum were collected in certain large scale dairy farm in Siping city according to the test program.The samples were detecting with double antibody sandwich ELISA to colostrums and calf serum which has been established.The results show that:1.the content change of IgG in colostrum is regularity from 0 hour to 7 day after parturition;2.the content change of IgG in the calf serum is regularity after sucking colostrum. It show that the content of serum IgG is closed to zero,then increased gradually.The content reachs to the highest level and keeps the level at about 36th hour after born,then the content decreased slowly with the time.And the content of serum IgG is keeping in low level constantly in control group.