Production, identification and use of PMSG-antiserum. A preliminary report

THERIOGENOLOGY Production, IdentificationandUseofPMSG-antiserum.APreliminary Report. A. Mike1 Jensen and T. Greve Institute for Animal Reproduction, Blilowsvej13, DK-1870 Copenhagen V. The unpredictability of.ovarian response to pregnant mare serum gonadotrophin (PMSG) constitutes a major obstacle for efficient use of egg transplantation in the bovine. The long half life of PMSG may contribute to this variability, and in order to neutralize possible surplus of PMSG it was decided to raise PMSG-antiserum in rabbit (RA) and hen (AA) and test this antiserum in immature (21 days old) mice using ovarian weight and ovarian morphology as indicator of PMSG-antiserum effect. Avian antiserum (AA) was produced by injecting 8 hens subcutaneously with 1000 WSG (Antex(R) L Pharmaceuticals, 1200 i.u./mg) every fortnight.'% hormone was em;lsf:ied in Freund's complete adjuvant for the first immunization and in subsequent immunizations Freund's incomplete adjuvant was used. Six out of 8 hens produced antiserum as revealed by Ouchterlony's test. Rabbit antiserum (RA) was produced by a commercial firm and presence of anti-PMSG was tested also by Ouchterlony's method. More detailed immunological assays including antigen-antibody crossed electrophoresis (Laurel1 1965) disclosed that the comnercially available PMSC-product contained a; least 15 different serumproteins (antigens). Because of its low isoelectric point (1.8) PMSG was expected to have a great electrophoretic mobility, but it migrated slowly and precipitated near the application well in the gammaglobulin area. In-vitro quantitation was impossible'becauseof the complexity of the product and the lack of a monospecific antiserum. The biological activity of RA was tested in mice treated with PMSG. Twenty-one day old mice were injected with 0, 1, 2, 3, or 5 i.u. PMSG SC. (dose response grouR) and 5 i.u. PMSG SC. t 10~1 PMSG-antiserum i.v. (treatment group). They were autopsied 24 hrs later and the ovarian weight in fresh and dried condition was determined. The ovarian weight (fresh) in relation to PMSG doses is presented in the figure, where a rather c7ear cut dose response curve was demonstrated. 5 i.u. PMSG gave rise to a maximum ovarian weight increase without overstimulation and this dose was chosen in the antiserum experiment. RA had a PMSG-neutralftfng effect since the mean ovarian weight (fresh) of the treatment group (7487+12Opg) was not significantly different (~(0.05) from the group that received saline (1405+14Dpg), but significantly lower than the group that was treated with 3 i.u. (4163t37Opg). The dose of antiserum (10~1) was high,but was chosen in ordeT;to demonstrate that PMSGantiserum raised in rabbits in fact did have a neutralizing effect most probably on the circulatory level of PMSG. It is likely, however, that this effect could be exerted bv smaller Quantities of PMSG-antiserum. The neutralizing capacitylof avian antiserum is currently being tested in mfce and both RA and AA will be used as mean of reducing warian overstimulation in cattle.

Laurell, C.-B.: Anal.Biochem. 10: 358, 1965.

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JANUARY

1980 VOL. 13 NO. 1