Lm. Berning et al., FUNCTIONAL VARIATION IN ENDOGENOUS AND EXOGENOUS IMMUNOGLOBULIN BINDING TO BOVINE NEUTROPHILS RELATIVE TO PARTURITION, American journal of veterinary research, 54(7), 1993, pp. 1145-1153
Ten healthy first- and second-lactation Holstein cows were observed fr
om 1 week before to 1 week after calving and at postpartum day 30 to d
etermine polymorphonuclear neutrophil (PMN) functional variation and i
mmunoglobulin binding profiles. Blood and mammary PMN were obtained 3
times weekly and within 24 hours of calving. Functional traits measure
d included phagocytosis of Staphylococcus aureus and in vitro chemotax
is through micropore filters in a Boyden chamber. Additionally, PMN we
re evaluated for endogenous binding of IgG1, IgG2, IgA, and IgM before
and after in vitro chemotaxis. Exogenous binding of the same isotypes
was determined after incubation in pooled colostrum, purified immunog
lobulin, and pooled sera. Phagocytosis results indicated a significant
and transient increase in percentage of milk PMN with associated, rat
her than phagocytosed, bacteria for 1 week after calving. Blood PMN ph
agocytosis was not significantly different during this period. Though
total chemotaxis was essentially unchanged, the percentage of PMN that
were unable to complete migration increased substantially on the day
of calving, an effect that disappeared by postpartum day 4. A signific
ant (P < 0.01) positive correlation (r = 0.29) between percentage of P
MN migrating completely through the micropore filter and percentage of
blood PMN with associated bacteria was observed. Changes were not obs
erved in endogenous immunoglobulin binding, with the exception of a pe
ak in relative fluorescence intensity for IgG, on the day of calving;
this disappeared within 2 days after calving. Correlations between rel
ative intensities of IgG2 and IgM, and percentage of mammary neutrophi
ls phagocytosing were 0.37 and 0.70. Exogenous binding of antibody to
blood neutrophils before chemotaxis was generally accomplished most ef
fectively by pooled colostrum, whereas use of pooled sera markedly red
uced binding and percentage and intensity of IgM in all cases. Binding
of all isotypes was slightly higher before than after calving. Incuba
tion of blood neutrophils in isotypes G1, G2, A, and M after chemotaxi
s yielded lower immunoglobulin binding among all isotypes, particularl
y IgM. Fluctuations in neutrophil function were observed immediately a
round parturition, and these changes correlated strongly with endogeno
us immunoglobulin-binding profiles.