VETS10018: Immune System Development

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Questions and Answers

What is the primary characteristic of primary immunodeficiencies?

They are usually acquired from infections.

They manifest after 16 weeks of age.

They are genetic in nature and typically rare. (correct)

They are always breed-associated.

Which of the following is a common indicator of immunodeficiency?

Response to standard antimicrobial treatments.

Single-site infections.

Severe allergic reactions.

Recurrent infections in young animals. (correct)

Which of the following breeds is associated with a specific immunodeficiency?

Siamese cat

Irish Setter (correct)

Golden Retriever

Labrador Retriever

Which type of immunodeficiency typically results from conditions such as drugs or infections?

Secondary immunodeficiency Signup and view all the answers

At what age can signs of primary immunodeficiency typically begin to appear?

Around 16 weeks of age Signup and view all the answers

What is the primary difference in antibody content between colostrum and milk?

Colostrum contains substantially more antibody than milk. Signup and view all the answers

What is the time frame during which gut permeability increases to allow better absorption of antibodies from colostrum?

6 to 24 hours Signup and view all the answers

Which component helps protect colostral proteins from being broken down in the gut?

Colostral trypsin inhibitors Signup and view all the answers

What type of antibodies are primarily transferred from maternal to foetal circulation through different types of placenta?

IgG, IgA, and IgM antibodies Signup and view all the answers

What occurs to neonatal glomeruli in terms of permeability after birth?

They are permeable for about 24 hours after birth. Signup and view all the answers

Which animal groups have different patterns of antibody absorption from colostrum?

Ruminants reabsorb antibodies after initial absorption. Signup and view all the answers

Which antibodies are considered absorbed but non-functional from colostrum?

Complement Signup and view all the answers

During the first 12 to 24 hours after birth, what is the peak serum concentration of immunoglobulins?

It occurs around 12 to 24 hours. Signup and view all the answers

What role does FcRn play in the context of colostrum absorption?

It aids in the absorption of antibodies through the enterocytes. Signup and view all the answers

Which factor can lead to the failure of colostral transfer?

Premature birth without colostrum. Signup and view all the answers

What is a consequence of maternal antibody presence in neonates?

It blocks the development of the neonate's immune response. Signup and view all the answers

Why might repeated vaccinations of neonates be necessary?

Because of variability in colostral intake and antibody catabolism. Signup and view all the answers

At what age should serum Ig concentration be measured to assess adequate colostral transfer?

24 hours after birth. Signup and view all the answers

What is the main reason colostrum is critical for certain animal species, such as horses?

There is no placental transfer of antibodies. Signup and view all the answers

Which test is used to measure equine IgG levels in the serum?

Snap™ Foal IgG Idexx. Signup and view all the answers

What is a possible symptom of failure of colostral transfer in neonates?

Enteric and respiratory disease. Signup and view all the answers

What causes neonatal isoerythrolysis in kittens?

Type B queens producing anti-A antibodies Signup and view all the answers

Which blood type is rare in dogs but can cause neonatal isoerythrolysis when sensitized?

Type DEA 1+/ DEA 1- Signup and view all the answers

What is a recommended step to prevent neonatal isoerythrolysis in kittens?

Use blood typing to match sire and dam Signup and view all the answers

Which breed is more susceptible to type B blood prevalence?

Birman Signup and view all the answers

What is a clinical manifestation of severe neonatal isoerythrolysis in kittens?

Tail tip necrosis Signup and view all the answers

What is the primary reason for the presence of antibodies in the colostrum of a dam?

Exposure to the sire's erythrocyte antigens Signup and view all the answers

What is typically observed in type A and AB cats in terms of antibody presence?

Low titred anti-B antibodies sometimes present in type A cats Signup and view all the answers

What type of placentation allows for the highest transfer of maternal antibodies to the fetus?

Haemochorial Signup and view all the answers

Which type of placentation occurs in dogs and cats?

Endotheliochorial Signup and view all the answers

In which type of placenta is no immunoglobulin transfer possible?

Synepitheliochorial Signup and view all the answers

What is the main characteristic of the synepitheliochorial placenta?

Trophoblast cells fuse with uterine epithelial cells Signup and view all the answers

How does passive transfer of maternal immunity affect vaccination in young animals?

It interferes with the response to vaccinations. Signup and view all the answers

What is the primary antibody type transferred in haemochorial placentation?

IgG Signup and view all the answers

Which of the following species is most likely associated with epitheliochorial placentation?

Horses Signup and view all the answers

Which condition might arise from a defect in maternal antibody transfer?

Hypoglobulinaemia Signup and view all the answers

Study Notes

Immune System Ontogeny & Neonatal Immunology

The lecture covers immune system development in young animals and neonatal immunology.
The course is VETS10018, Animal Systems and Professional Life 1.
This topic focuses on placenta types in animals and their impact on maternal immunity transfer.

Intended Learning Outcomes

Identify and describe the four main placenta types in animal species.
Outline the variations in maternal immunity transfer between different placenta types.
Discuss how maternal immunity transfer influences vaccination in young animals.
Explain clinical indications of immunodeficiency.
Describe and summarise neonatal isoerythrolysis (NI), specifically focusing on foals.
Identify other species susceptible to NI.

The Different Types of Placentas

Placentas are classified based on the number of layers separating maternal and fetal circulation.
Four main types are:
- Epitheliochorial (e.g., horses, pigs)
- Synepitheliochorial (e.g., ruminants)
- Endotheliochorial (e.g., cats, dogs)
- Haemochorial (e.g., primates, rodents, rabbits).

Passive Transfer of Immunity

This describes the transfer of antibodies (immunoglobulins, Ig) from one individual to another.
Primarily, this happens during the first few days of newborn life through colostrum.

Passive Transfer Depends on Placentation Type

The transfer of maternal antibodies depends on the type of placenta.
Haemochorial placentation (e.g., primates) allows the passing of high levels of serum IgG (important antibody) to the fetus, as an adult level is present.
Endotheliochorial placentation (e.g., cats, dogs) allows passage of a limited amount of maternal immunoglobulins (IgG) (5-10% of adult levels).
Synepitheliochorial placentation (e.g., ruminants) does not allow transfer of immunoglobulins.
Epitheliochorial placentation (e.g., horses, pigs) does not allow transfer of immunoglobulins.

Colostrum and Milk Composition

Colostrum contains substantially more antibodies than milk.
This high antibody concentration in colostrum is essential for neonatal health, especially when newborns lack maternal antibodies.
Colostrum has a high permeability in the first 24 hours of life, enabling the absorption of antibodies.

Absorption of Colostrum

Gut permeability increases in the first 6-24 hours after birth, facilitating colostrum absorption.
Colostral protein is protected from proteolytic enzymes in the gut by low proteolytic activity, IgA secretory component, and colostral trypsin inhibitors.
Other components like complement proteins, maternal lymphocytes are also absorbed, but may not retain their function.
Peak serum IgG concentration is reached at 12-24 hours post-birth.
There is some loss of IgG through neonatal glomeruli permeability, which can be seen later as transient proteinuria.
Differences exist between horse/pig and ruminant colostrum absorption.

Neonatal Vaccination

Colostral antibodies can hinder the development of the neonatal immune response until the maternal antibodies are broken down.
Neonates may not respond to vaccines properly if maternal antibodies are still present in circulation.
Vaccination of neonates can vary depending on the amount of antibodies present and their turnover in the body.

Neonatal Immunodeficiencies

Failure of colostrum transfer can lead to enteric and respiratory issues or septicemia.
Causes of failure include premature birth, poor lactation, poor quality colostrum, failure to suckle, and failure to absorb.
Diagnostic testing to determine the level of IgG (antibodies) in the newborn after 24 hours after birth is used to determine if colostrum transfer was adequate.
Primary immunodeficiencies are genetic and rare.
Secondary immunodeficiencies are acquired and more common, arising from factors like drugs, infections, or underlying diseases.
Signs of immunodeficiency in animals include chronic or recurrent infections at multiple sites, failure to react to standard antimicrobials, and infections with unusual pathogens.
Some breeds of animals have an increased risk of immunodeficiency conditions.

Neonatal Isoerythrolysis (NI)

NI is an isoimmune haemolytic anaemia condition impacting newborns.
It's caused by maternal antibodies targeting the neonate's erythrocytes.
Maternal antibodies can be present in the colostrum due to either sire erythrocyte antigen sensitivity or spontaneously-occurring antibodies.
Examples of this condition exist in foals and kittens, often with blood group incompatibilities between the dam and sire.
NI symptoms can range from subclinical disease to severe haemolytic anaemia, jaundice, haemoglobinuria, weakness, lethargy, reluctance to suckle, and potentially death.
Prevention and treatment strategies in cats involve preventing incompatible mating by blood typing, carefully assessing antibody levels in the dam's serum, and potentially providing colostrum replacement using type A cat serum.

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Description

This quiz explores the development of the immune system in young animals and the principles of neonatal immunology. It focuses on the four types of placenta in animals and their influence on maternal immunity transfer and vaccination. Additionally, it covers immunodeficiency and neonatal isoerythrolysis in foals and other species.