Interferon-c response in in vitro lymphocyte
stimulation
The following ELISA condition was standardized as optimum
for IFN-c assay on the basis of differences of optical
densities recorded amongst various concentration of rIFN-c
used as positive and without rIFN-c as negative control:
Concentration of mouse anti-bovine IFN-c:biotin 03 lg/ml,
IFN-c detection up to 20 pg/ml, dilution of culture supernatant
1:10 and the mouse anti-bovine IFN-c and straptavidin:
HRP conjugate were used in 5 lg/ml and 5000-1
dilution, respectively, as per the manufacturer’s instructions.
The standard graph of bovine recombinant IFN-c
was plotted (Fig. 2) and a significant difference in SI and
OD value up to 200 pg/ml was recorded. The lowest
detectable value of IFN-c was 20 pg/ml and SI at this level
was 1.16 which was greater than maximum SI calculated
from individual calf. The pattern of expression of IFN-c
was shown in Fig. 3. The SI of all the groups of animals
were within a range of 1–1.14 and there were no significant
differences in IFN-c expression amongst the animals of all
the groups.