The MALDI sequencing of the putative Vtg band resulted in 46 peptides (data not shown) with significant homology (Mascot ion score > 77) to fourVtg proteins from three different species in the NCBI database (Table 1).
Of the four Vtg proteins, three different isoforms were represented: Vtg, Vtg 2 and Vtg 3.
We compared the presence/absence of Vtg in 28 plasma samples representing 10 individual males and 32 plasma samples from 11 individual famales over the 2009 season.
We found a significant difference between the number of Vtg positives in the sexes (F1.19 = 10.72, P= 0.0040).
We did not detect Vtg among any male samples whereas 21 of the 32 female plasma samples were positive for Vtg.