Effects of anti-progesterone murine monoclonal antibodies on plasma progesterone concentrations and on anti-mouse reactions in cyclic pigs

• Published in: Animal reproduction science Vol. 37; no. 1; pp. 51 - 64
• Main Authors: Booman, P., Schakenraad, J.M., Veerhuis, R., van de Wiel, D.F.M., Koops, W., Tieman, M., Kruijt, L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.1994
• Subjects: ANTICORPS MONOCLONAL; ANTICUERPOS MONOCLONALES; CERDO; CICLO ESTRAL; CYCLE OESTRAL; IMMUNE RESPONSE; IMMUNITE PASSIVE; Immunization, passive; INMUNIDAD PASIVA; MONOCLONAL ANTIBODIES; OESTROUS CYCLE; PASSIVE IMMUNITY; Pig; PORCIN; PROGESTERONA; PROGESTERONE; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; SWINE; Monoclonal antibodies; Immunization, passive; Progesterone; Pig
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/0378-4320(94)01320-9

The effect of murine anti-progesterone monoclonal antibodies on plasma progesterone levels was studied in cyclic gilts. Intravenous injection of increasing amounts of anti-progesterone antibodies (50–500 mg IgM) resulted in a concomitant rise in levels of antibody-bound progesterone (6–25 ng ml −1). At the same time a significant rise in plasma concentrations of total progesterone (3–21 ng ml −1) was observed immediately after the administration of antibodies. The net effect of progesterone binding by the monoclonal antibody on circulating progesterone levels was significant for the group of animals injected with at least 50 mg of antibody. The effect, however, was relatively small (1–11 ng ml −1) and more or less independent of the quantities of antibody administered. Plasma levels of circulating antibody capable of binding progesterone were still detectable at the end of the experimental period (± 13 days after injection). On the other hand, it appeared that in all animals, except the one injected with the largest quantity (500 mg) of antibody, the concentration of antibody-bound progesterone started to decrease as early as the first day after injection and was below detectable levels within 1 or 2 days. Mechanisms that may control the initial increase in progesterone levels and enable the animals to maintain adequate levels of free progesterone in circulation are discussed. Administration of a minimum dose of 32 mg antibody resulted in an anti-mouse immune response after the first injection, and subsequently in a neutralization of the anti-progesterone monoclonal antibodies immediately after the second injection. When smaller quantities of antibody (≤ 20 mg) were used, anti-mouse antibodies were detected only after the second or third injection.