This work was supported by NIH grant HD 16586.
An IgG-Fc Binding Protein in Seminal Fluid*
Article first published online: 9 MAY 2013
American Journal of Reproductive Immunology
Volume 3, Issue 1, pages 23–27, January 1983
How to Cite
WITKIN, S. S., RICHARDS, J. M., BONGIOVANNI, A. M. and ZELIKOVSKY, G. (1983), An IgG-Fc Binding Protein in Seminal Fluid. American Journal of Reproductive Immunology, 3: 23–27. doi: 10.1111/j.1600-0897.1983.tb00207.x
- Issue published online: 9 MAY 2013
- Article first published online: 9 MAY 2013
- Accepted July 28, 1982
- Seminal fluid;
- Fc receptors
ABSTRACT: Human seminal fluid, at low dilutions, prevented the binding of aggregated human IgG (AHG) to bull spermatozoa. Seminal fluids from vasectomized men were also inhibitory. Preincubation of the seminal fluid with the spermatozoa prior to washing and addition to AHG had no inhibitory effect, indicating that the fluid component was reacting directly with AHG. Human seminal fluid was fractionated by gel exclusion chromatography on Ultrogel AcA-34, and AHG inhibitory activity was found in fractions corresponding to a molecular weight of 94,000. The activity in this fraction was stable to boiling for 10 min. It was sensitive to pronase but resistant to glycosidase, phospholipase C, neuraminidase, ribonuclease, and deoxyribonuclease, indicating that it was a protein. The gel filtration fraction readily bound recrystallized Fc and AHG; IgG was bound to a lesser extent, and no reactivity was observed with F(ab')2, IgA, or IgM. Thus, the seminal fluid fraction appeared to specifically react with the Fc portion of IgG. The seminal fluid Fc-binding protein was isolated by affinity chromatography on Fc coupled to CNBr-activated Sepharose 4B. Scatchard analysis revealed that the binding of the seminal fluid Fc-binding protein to recrystallized Fc is reversible and had a Kd of approximately 3 × 10−6 M.