Monitoring of immunological response
The humoral immune response to rHaa86 antigen was
monitored by indirect ELISA. The ELISA was optimized
and antigen was applied to the microtiter plate in a concentration
of 6 lg/ml. The collected sera were diluted into
1:500 and were used in triplicate wells. Sheep anti-bovine
IgG, IgG1 and IgG2:HRPO conjugate (AbD serotec, UK)
were used at a dilution of 1:10,000 as secondary antibody.
The peroxidase mediated colour development was performed
at room temperature with o-phenylene diamine
dihydrochloride (OPD) (Pierce, USA) in citrate buffer, pH
5.0. The reaction was stopped with 50 ll of 3 N HCl per
well, and absorbance was recorded by microplate ELISA
reader (Tecan-Sunrise, Austria), as the mean OD492 of
triplicate samples.