Lecture 19 - Fetal & Neonatal Immunity Flashcards
What immune system is present in the first trimester
primary lymphoid formed
secondary lymphoid forming
What immune system is present in the second trimester
complement and granulocytes
tonsils/peyer’s patches
What immune system is present in the third trimester
fully developed adaptive immune system
what two factors are in-utero infections dependent on
- organism
- age of fetus
What are the two biotypes of BVD
cytopathic - kills cells
noncytopathic - doesn’t kill cells
What are the three outcomes of an in-utero infection
- death
- malformation
- successful immune response
What do we call a calf that receives a noncytopathic infection from the day 50-120
persistently infected calf
What is the danger of having a persistently infected calf in the herd
sheds large amounts of the virus but is asymptomatic
T/F: neonate immunity is more efficient than an adult
False
T/F: passive immunity is critical for the neonate
True
What decreased innate defense mechanisms are seen in immunodeficient neonates
- complement activity
- neutrophil and macrophage activity
- interferon production
- NK cell function
What decreased adaptive mechanisms are seen in immunodeficient neonates
- lymphocyte mitosis
- no memory B/T cells
How do we supplement neonates that are not fully immunocompetent?
placental/colostral transfer and milk
What immunoglobulin is present in neonate supplementation
IgG
T/F: placentation type determines the ability of antibodies to be transferred in utero
TRUE
What placentation has the least transfer of immunoglobulins
epitheliochorial (6 layers)
What species are epitheliochorial and are at higher risk for underdeveloped immune systems
pig, horse, donkey
What placentation has the most transfer of immunoglobulins
hemendothelial (1 layer)
What species are hemendothelial and at a low risk for underdeveloped immune systems
rodents
What is colostrum
produced in the last weeks of gestation high in antibodies and other immune components
What are the specialized parts of GI epithelial cells
Fc receptor
non-selective pinocytosis
when does uptake stop in neonates?
24 hours after birth
Why does uptake stop in neonates?
cells are replaced resulting in gut closure
What immunoglobulin is present in the mammary gland
IgA
Around what week after birth do maternal antibody levels drop to meet those of the developing neonate? What is usually done around this time?
4/5 weeks (window of susceptibility)
vaccination occurs at this time
What cytokine that stimulates initial immune response is present in milk
IFN-y
What vitamin is thought to be essential for immune function and will be supplemented in pigs
Vitamin D
What is the predominant cell type transferred to neonates in passive transfer
neutrophils and macrophages
What immunoglobulin do passively transferred B cells secrete
IgA
What may prevent lymphocytes transferred in passive immunity from having lasting impact on neonates?
- pasteurization process will kill some cells
- closure of GI cells
- short life of naive lymphocytes
What is the predominant antibody isotype in colostrum?
IgG
What is the risk of vaccinating too early?
neutralization of vaccine
What is the risk of vaccinating too late?
not enough time to develop a response before a challenge
What term do we associate with antibodies transferred to neonate by their mother
Maternal-derived antibodies (MDA)
What are the 3 steps to negative feedback of IgG production
- complex formation
- Ig/Fc binding
- dephosphorylation
What is the average gestation length for equines
320-370 days
What does the term “dummy foal” refer to
decreased/interrupted availability to oxygen during birth
What is considered the normal IgG snap test range
> 800 mg/dL
Partial failure would be at ____ mg/dL while complete failure would be at _____ mg/dL
400-800; < 400
How can you assess colostrum quality?
- appearance
- brix refractometer (protein content)
- colostrometer (density)
In what case would IV plasma be given to a neonate
to address FTPI and in abnormal cases where tubing is not viable
