Neonatal Immunity

Question 1

Innate Immunity

Answer 1

Initial resistance to infections from birth

Question 2

How is the adaptive immune system for animals with a long gestation period?

Answer 2

Adaptive immune system is fully developed at birth but can’t function at adult levels for several weeks

Question 3

How is the adaptive immune system for animals with a short gestation period?

Answer 3

Adaptive immunity is less developed @ birth

Question 4

Development of the immune system

Answer 4

1. B cells appear soon after development of spleen and LNs (no antibodies until late fetal life)
2. Ability to respond to antigens develops rapidly after lymphoid organs appear
3. Serum of newborn animals is deficient in some complement (more susceptible to infection)

Question 5

When are neutrophils capable of phagocytosis?

Answer 5

@ 90 days post-conception in fetal pigs

Question 6

How is immune response shown in serum of newborns?

Answer 6

By lymphoid hyperplasia and elevated immunoglobins (suggest infection in embryo)

Question 7

What does immune response depend on in the fetus?

Answer 7

On the state of immunological development (days of gestation)

Question 8

Bluetounge in ewes

Answer 8

Disease @ 50 days causes severe disease in fetal lambs
@ 100 days only causes mild disease

Question 9

Parvovirus for piglets

Answer 9

Before 55 days of gestation it’ll cause abortion or still birth in piglets
After 72 days piglets will develop antibodies to parvo to survive

Question 10

What does the transfer of immunity depend on?

Answer 10

The type of placenta

Question 11

Placenta of primates, rodents and humans?

Answer 11

Hemochorial placenta
Maternal blood is in direct contact with trophoblast
Allows transfer of IgG

Question 12

Placenta of dogs and cats

Answer 12

Endotheliochorial
5-10% of IgG may transfer to fetus
Most obtained through colostrum

Question 13

Placenta of ruminants

Answer 13

Syndesmochorial
No trans-placental transfer of Igs
Newborns receive maternal Igs through colostrum
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Question 14

Placenta of Horse and pigs

Answer 14

Epitheliochorial
No trans-placental transfer of Igs
Newborns receive maternal Igs through colostrum

Question 15

Colostrum

Answer 15

Contains accumulated secretions of mammary glands over the last few weeks of pregnancy with proteins from the blood

Question 16

What is colostrum rich in?

Answer 16

IgG and IgA
Lymphocytes and cytokines

Question 17

What is the predominant Ig in colostrum in domestic animals?

Answer 17

IgG

Question 18

Composition of colostrum and milk in humans and primates

Answer 18

IgA predominates

Question 19

Composition of colostrum and milk in dogs, pigs and horses

Answer 19

IgG in colostrum
IgA in milk

Question 20

Composition of colostrum and milk in cats

Answer 20

IgG in colostrum
More IgG than IgA in milk

Question 21

Composition of colostrum and milk in ruminants

Answer 21

IgG1 in both

Question 22

What happens to colostrum after absorption?

Answer 22

Colostrum proteins aren’t degraded
IgGs bind to receptors (FcRn) on intestinal epithelial cells then absorbed into blood

Question 23

When is gut permeability for absorption of Igs the highest?

Answer 23

Immediately after birth, declines after 6 hrs

Question 24

Neonatal Fc receptor (FcRn)

Answer 24

Prevents IgG degradation
Recycling of IgG and maintaining IgG levels

Question 25

Where are Fc receptors found?

Answer 25

Phagocytes (macrophages and monocytes)
Granulocytes (neutrophils and eosinophils)
Lymphocytes (NK cells and B cells)

Question 26

No absorption of Igs after ____________

Answer 26

24 hrs

Question 27

Colostrum fed in the first day

Answer 27

Calves and foals should be fed 1 L of colostrum within 6 hrs of birth
Peak serum levels 12-24 hrs after birth

Question 28

What are the reasons for failure passive transfer (FPT)

Answer 28

Production failure
Ingestion failure
Absorption failure

Question 29

Production failure

Answer 29

Premature birth, excessive dripping b4 birth, production of low quality colostrum

Question 30

Ingestion failure

Answer 30

Sheep, goats, pigs inadequate intake due to multiple birth, poor mothering, weak or sick newborn and sick mother

Question 31

Absorption failure

Answer 31

Problem in foals (25% newborns)
Require min of 800 mg/dL serum IgG for protection

Question 32

When do you diagnose FPT in foals?

Answer 32

After 18 hrs using zinc sulfate turbidity tests (zinc sulfate + serum)
Complete failure: SErum IgG 400 mL/dL
Partial: less than 800 mg/dL

Question 33

Other tests to diagnose FPT

Answer 33

Single radial immunodiffusion/ Mansini Imuno Diffusion (18-24 hrs)
Latex agglutination test using whole foal blood or serum
SNAP test

Question 34

How do you manage FPT?

Answer 34

Feed additional 2-3 L colostrum by bottle or nasogastric tube in 3-4 doses at hourly intervals

Question 35

How do you manage FPT in foals older than 15hrs?

Answer 35

An i/v plasma infusion
frozen horse plasma commercially available

Question 36

What interferes with vaccination in young animals?

Answer 36

Maternal antibodies
Young animals don’t respond to active immunization because of neutralization by maternal antibodies

Question 37

When do you vaccinate pups?

Answer 37

Maternal Abs decline by 6 weeks
Vaccination given 10-12 weeks, earliest 6-9 weeks

Question 38

IgY

Answer 38

Transported from hens serum to egg yolk
Found at a higher concentration than hen serum

Question 39

In chicks where is IgA accquired?

Answer 39

From oviduct secretions with albumin