Neonatal immunity (year 2) Flashcards
what is the first lymphoid structure to form?
Thymus and then secondary lymphoid organs
are the levels of circulating macrophages and neutrophils normal in the neonate?
yes but function is impaired
what impairs the function of circulating neutrophils and macrophages in the neonate?
at birth maternal hormones flood the neonate this triggers an anti-inflammatory response
what are the levels of complement like in the neonate?
low as phagocytosis and opsonisation is impaired due to the limited neutrophil and macrophage function
how do animals get maternally derived antibodies?
colostrum and placenta
how do neonates get lymphocytes?
from colostrum but their survival is questioned
how much passive immunity is transferred from placenta and colostrum in dogs/cats?
5% placental
95% colostral
how much passive immunity is transferred from placenta and colostrum in ruminate, pigs and horses?
100% colostral
describe the process by which immunoglobulins enter milk
active trader from blood under hormonal influence (oestrogen and progesterone)
what is the main antibody found in colostrum?
IgG
how does the immunoglobulin content change as colostrum turns into milk?
more IgA and less IgG
what else does colostrum contain other than immunoglobulins?
cytokines (growth factors)
other hormones
why is it essential colostrum is is ingested within the first few hours of life?
enzyme levels are low/blocked so proteins can reach the small intestine
newborns briefly have receptors for IgG present on the intestinal epithelia
what immunoglobulins are selectively absorbed in pigs/horses?
IgG and IgM
IgA stays in the intestine
how long after birth in ruminants until absorption begins to decline and then reaches nothing?
starts declining after 6 hours
no absorption by 24 hours
how is the rumen and abomasum bypassed in ruminants?
oesophageal groove
how may passive transfer failure?
neonate unsuckled - multiple births or damaged teats
poor production of Ig - premature lactation or dripping
poor absorption of Ig
what does IgG and IgA prevent?
IgG - septicaemia
IgA - enteric disease
how is failure of passive transfer diagnosed?
measuring serum IgG using a hydrometer
how can failure of passive transfer be treated?
additional colostrum up to 15 hours of age
IV plasma over 15 hours of age
what giving IV plasma to treat failure of passive transfer what must it be free of?
anti-erythrocyte antibodies
maternally derived antibodies inhibit Ig synthesis, what does this mean for vaccinations?
will prevent the vaccine from working and being successful
at what age is the window of suspetibilkity?
10-12 weeks
