2.3. Chromatography and mass spectrometry assays
Chromatographic fractionation of H. lunatus venom was
performed using high performance liquid chromatography
(HPLC). Briefly, 1 mg of crude venom was applied to
a reverse phase column. The column used in this assay was
a Shimadzu-Pack CLC-ODS C18 (6 150 mm) eluted at
1 mL/min with a linear gradient of 0.1% TFA in water and
acetonitrile, solutions A and B, respectively. After column
equilibration the venom fractions were separated with
a linear gradient from solution A to 60% solution B, running
for 60 min.
Fractions were then subjected to MALDI-TOF-TOF analyses.
MS analysis was performed using a MALDI-TOF-TOF
AutoFlex III (Bruker Daltonics) instrument in positive/
reflector mode controlled by the FlexControl software.
Instrument calibration was achieved by using Peptide
Calibration Standard IV (Bruker Daltonics) as a reference
and using sinapinic acid as a matrix. The peak was spotted
to MTP AnchorChip 400/384 (Bruker Daltonics) targets
using standard protocols for the dried droplet method.
2.4. Immunological studies
2.4.1. Immunization protocols
Adult New Zealand female rabbits were used for the
production of anti-H. lunatus and anti-T. serrulatus venom
antibodies. After collection of pre-immune sera, the
animals received an initial subcutaneous injection of 100 mg
of whole venom in complete Freund’s adjuvant (day 1).
Three booster injections were made subcutaneously 14, 21
and 28 days later with a lower dose (50 mg) in incomplete
Freund’s adjuvant. The animals were bled one week after
the last injection.