XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Posters
48.
EPITOP of Iva-520 MONOCLONal aNTIBODY ON THE
BovINE SPErm CD46 MOLECULE
Jana Antalíková, Jana Jankovičová, Katarína Michalková,
Michal Simon and Ľubica Horovská
Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences,
Ivanka pri Dunaji, Slovak Republic, Centre of Excellence of Slovak Research and
Development Agency „Biomembranes 2008“.
Membrane cofactor protein (MCP/CD46) serves as a cofactor for the factor I-mediated
cleavage of C3b and C4b complement components deposited on self tissues and probably
plays also a role in reproduction. In Human and also New World monkeys the unique
pattern of sperm CD46, different from other cells and tissues were detected. The bovine
sperm isoform remains unclear. Using the monoclonal antibody (mAb) IVA-520 against
bovine CD46 (obtained after intrasplenic immunisation of BALB/c mice with intact bull
spermatozoa) the expression of CD46 on bovine spermatozoa has been detected. By SDS-
PAGE of detergent solubilised sperm proteins and immunoblotting with mAb IVA - 520
we found out two bands with molecular weight of 53 and 43 kDa - different from common
blood cells and tissue isoforms (46-52 lower band, 60-68 upper band), resistant to
digestion with N-glycosidase F and disappearing after neuraminidase treatment (not in
other cells and tissues). The treatment of suspension of whole spermatozoa with neuraminidase
decreased the binding ability of mAb IVA-520 on sperm CD46 molecule. We
suppose the posttranslational modification of the molecule are sperm-specific, the part
of bovine CD46 epitope recognised by mAb IVA - 520 is formed probably by the serine,
threonine and-proline rich region (STP) of MCP molecule and the sialic acid probably
takes part in an epitope conformation of mAb IVA-520.
Acknowledgement: This work was supported by grant VEGA-2/0001/09 and in part by
the grant VVCE-0064-07.
168 XXII. Biochemistry Congress, Martin