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| − | {{review}}
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| − | {{toplink
| + | =[[Materno-Fetal Immunity - Introduction]]= |
| − | |thispagemap= Materno-fetal immunity(Concept Map) - WikiBlood
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| − | |linkpage=Immunology
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| − | |linktext =IMMUNOLOGY
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| − | |pagetype =Blood
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| − | }}
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| − | =Introduction=
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| − | Passive immunity occurs when 'preformed' antibodies are made in one animal and passed onto another. For example a cow passes on her own antibodies to her calve via colostrum (first milk after parturition) and milk.
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| − | Antibodies can be transferred to other individuals via colostrum, milk, crossing of the [[Gestation -Placenta - Anatomy & Physiology|placenta]], [[Vaccines - WikiBlood|vaccination]], and plasma transfusions.
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| − | Neonates require maternal antibodies because:
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| − | '''1. They have poorly developed immune systems and are immunocompromised at birth.'''
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| − | '''Lymphocytes in neonates:''' Increased numbers of mostly mature and functional T and B lymphocytes are found in the blood. However the ability to mount an immune response to certain antigens is absent. This may be due to:
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| − | # Immaturity of some cells - T helper cells, B cells and Antigen presenting cells.
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| − | # Lack of expression of genes encoding receptors for each antigen.
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| − | # The presence of maternal antibody which binds antigen and removes it thus preventing the neonate from developing active immunity.
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| − | '''Antibodies in neonates:'''
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| − | '''2. Neonatal mucosal surfaces are particularly vulnerable'''
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| − | '''3. Colostral and milk [[Immunoglobulins|antibodies]] protect neonates from infections'''
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| − | =Passive transfer via [[Gestation -Placenta - Anatomy & Physiology|placenta]]=
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| − | {| style="width:60%; height:200px" border="1" align=center
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| − | !'''SPECIES'''
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| − | !'''PLACENTA TYPE'''
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| − | !'''IgG TRANSFER?'''
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| − | |-
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| − | | human
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| − | | haemochorial
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| − | | YES
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| − | |-
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| − | | dog/cat
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| − | | endotheliochorial
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| − | | SMALL AMOUNT
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| − | |-
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| − | | horse/ruminant/pig
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| − | | epitheliochorial
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| − | | NO
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| − | |-
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| − | |}
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| − | Due to the placentas of ruminants and horses having 5 tissue layers between the maternal and fetal circulation there is no transfer of [[Immunoglobulins|antibodies]] across the placenta.
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| − | =Passive transfer via colostrum=
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| − | [[Image:Transfer of IgG across intestine via FcRn.jpg|right|thumb|150px|Transfer of IgG across intestine via FcRn-Brian Catchpole RVC 2008]]
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| − | [[Image:PASSIVE TRANSFER.jpg|right|thumb|150px|PASSIVE TRANSFER-M. Maidment RVC 2008]]
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| − | [[Image:Colostrum Intake.jpg|right|thumb|150px|Colostrum Intake - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]]
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| − | In the dam [[Lymphoreticular System - Anatomy & Physiology#B cells|B cells]] migrate from the [[Regional Lymphoid Tissue - Anatomy & Physiology|MALT]] to the [[Lactation - The Mammary Gland - Anatomy & Physiology|mammary gland]] where [[Immunoglobulins|antibodies]] are secreted into the colostrum and milk.
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| − | ==Colostrum== is the pre-milk fluid usually thick and yellow in colour that is secreted from the mammary glands for only a short time after birth by most mammals.
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| − | * There is species variation with the composition of colostrum.
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| − | *It contains:
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| − | ** Immune factors - [[Immunoglobulins|immunoglobulins]], lactoferrins, protein-rich polypeptides, leukocytes, cytokines, trypsin and protease inhibitors.
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| − | ** Growth factors: EgF, IGF-I, IGF-II, FyF, PDGF, TgF A and B and growth hormone (GH) - which aid in rebuilding damaged body systems and stimulating the bodies metabolism to burn fat for energy instead of the bodies own muscle tissue.
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| − | ** Vitamins and minerals.
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| − | *[[Immunoglobulin G|IgG]] is most abudant in colostrum, followed by [[Immunoglobulin A|[[IgA]]]] and [[Immunoglobulin M|IgM]]
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| − | * During the first 30 hours of life, [[Immunoglobulins|immunoglobulins]] are absorbed through the intact [[Jejunum - Anatomy & Physiology|jejunum]] and pass to the [[lacteals]], [[Lymphatic Vessels - Anatomy & Physiology|thoracic duct]] and into the systemic circulation.
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| − | * The first diagram (entitled Transfer of [[Immunoglobulin G|IgG]] across intestine via FcRn) shows [[Immunoglobulin G|IgG]] being present in the intestine of a neonate, from the ingestion of colostrum. Fc receptors (FcRn) are present on the surface of the intestinal epithelial cell in neonates for the first 30 hours. The [[Immunoglobulin G|IgG]] binds to the receptors and is transported through the cell by pinocytosis and released into the lacteals unchanged.
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| − | * The capacity for immunoglobulin absorption progressively declines from birth due to the FcRn only being present for a limited period of time. After 6 hours a third of the FcRn are non functional.
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| − | * It is essential that all animals with epitheliochorial placentas (ruminants, horses, pigs) receive adequate colostrum intake within the first 4 hours (optimal absorption period) of life because no transfer of [[Immunoglobulins|immunoglobulins]] via the placenta can occur.
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| − | * The second diagram (entitled Passive Transfer) shows the relationship between passive immunity from the mother and the neonatal production of antibodies.
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| − | * Colostrum also provides the neonate with a vital energy source to generate heat and enzymes to aid digestion of colostrum products.
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| − | ==Milk== is the primary source of nutrition for young before they are able to digest other food.
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| − | In non-ruminants [[Immunoglobulin A|'''[[IgA]]''']] is most abundant, followed by [[Immunoglobulin G|IgG]] and [[Immunoglobulin M|IgM]]; [[Immunoglobulin G|'''IgG''']] is most abundant in ruminant milk.
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| − | * Milk has approximately 1/100th of the antibody concentration of colostrum.
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| − | * Between colostrum and milk there is a period where a substance similar to them both is secreted called transition milk. By approximately 5-7 days milk is being secreted.
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| − | * The capacity for [[Immunoglobulins|immunoglobulin]] absorption from the gastrointestinal tract is completely absent 30 hours post partum so the main role of milk (apart from a nutritional source) is to protect the intestinal lining.
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| − | * [[IgA]] remain in the intestine and attach to the intestinal villi protecting the intestinal lining against enteric pathogens.
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| − | <big><center>'''''Colostrum feeding of lambs and kids'''''</center></big>
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| − | {| style="width:60%; height:200px" border="1" align=center
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| − | !'''Colostrum source'''
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| − | !'''Acceptability'''
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| − | |-
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| − | | Dam with good quality colostrum
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| − | | Best source
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| − | |-
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| − | | Another female in the flock/frozen colostrum (must be thawed properly)
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| − | | Best substitute
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| − | |-
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| − | | A female in another flock (similar disease status)
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| − | | Next best substitute
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| − | | Ewe or doe
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| − | | There is a risk of transferring diseases for example Maedi Visna and Caprine Arthritis and Encephalitis (CAE) viruses.
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| − | |-
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| − | | Cow
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| − | | Lower in nutrition (milk from coloured breeds is higher in fat), need to feed 1/3 more volume, Johne's risk
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| − | |-
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| − | | Colostrum supplement powder
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| − | | Nutritious, contains antibodies, expensive
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| − | |-
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| − | | Lamb or kid milk replacer
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| − | | Only feed after first 24 hours of life as it is not an adequate substitute for colostrum
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| − | |}
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| | ==Maternal Immunity in Birds== | | ==Maternal Immunity in Birds== |