Passive Immunity

1
Passive Immunity

• Transfer of specific Abs between individuals.
• Short-lived, no memory
• dependent on Ab half-life
• Artificial
• antiserums, antitoxins
• Natural
• mother to fetus, infant

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2
Development of Antibody Responses in Domestic
Animals

• Gestation Period
• Cow 280
• Sheep 145
• Pig 115
• Horse 340
• Dog 60

• Antibody Producing Ability
• 73 days
• 41 days
• 58 days
• 200 days
• 40 days

3
Transfer via Placenta

• Hemochorial
• rodents, primates
• maternal blood contacts trophoblast
• maternal IgG fetal IgG

4
Transfer via Placenta

• Hemochorial
• rodents, primates
• maternal blood contacts trophoblast
• maternal IgG fetal IgG
• Endotheliochorial
• cats, dogs
• limited IgG transfer

5
Transfer via Placenta

• Hemochorial
• rodents, primates
• maternal blood contacts trophoblast
• maternal IgG fetal IgG
• Endothelialchorial
• cats, dogs
• limited IgG transfer
• Syndesmochorial
• Ruminants
• no transplacental passage of Ig

6
Transfer via Placenta

• Syndesmochorial
• Ruminants
• Uterine Tissue/Chorionic
• Epithelium
• No Transplacental passage of Ig
• Epitheliochorial
• Horses and Pigs
• Uterine Epith/Chorionic Epith
• No Transplacental Transfer

7
Transfer via Colostrum, Milk

• Colostrum
• Rich in IgG and IgA
• Accum. Secretions of Mammary gland
• Milk - mostly IgA (ruminants IgG)

8
Transfer via Colostrum, Milk

• Colostrum - Most IgG derived from serum 50 of
  IgA from Serum and rest from local production.
• Milk 30 of IgG and 10 of IgA from Serum

9
Transfer via Colostrum, Milk

• Absorption-Igs Not Degraded
• low GI proteolytic activity
• trypsin inhibitors in colostrum
• Ig binds FcRn on intestinal epithelium
• Specialized Fc Receptor
• Actively taken up by epith. cells by Endocytosis
• Reaches Circulation
• Permeability limited duration
• Highest at birth and declines after 6 hrs.

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Passive Transfer of Antibodies from Mare to Foal
11
Failure of Passive Transfer (FPT)

• Causes
• Production failure
• premature birth or lactation
• excessive mammary dripping
• Ingestion failure
• multiple births, poor mothering
• newborn - weakness, poor suckling drive, physical
  defect
• Absorption failure
• premature closure of gut

12
FPT (Contd.)

• Mares
• Production failure
• Colostrol IgG inadequate in 28 of mares
• Normal concn 3000-8500 mg/dL
• lt3000 mg/ml inadequate
• Foals
• Absorption Failure in 25 of foals
• normal concn is gt800mg/dL

13
FPT Diagnosis Treatment

• Diagnosis
• Zinc-sulfate turbidity test
• Single radial immunodiffusion
• Latex agglutination
• ELISA
• Treatment
• antibiotic treatment for infections
• artificial passive transfer of Ab

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Immunoglobulin Levels in Newborn Foal
15
When is Treament Needed?

• IgG Concn lt200mg/dL in serum
• Foals have not nursed within 6 hrs after birth
• Foals that have nursed Colostrum (lt1000 mg/dL)

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Treatment

• 2-3 Liters of good quality of colostrum
• Serum or Plasma can be given orally
• Foals gt15 hours may need plasma infusion

17
?d T Lymphocytes
18
?d T Lymphocytes

• Up to 60 of PBL in Ruminants
• Respond in MLR
• Sheep
• 60 of T cells in blood in new-born lambs
• 30 by 1 year and 5 by 5 years
• Pigs
• Significant portion of circulating T cells
• Important in defending epithelial surfaces and
  early CMI in newborns?