The selection of antibodies with defined desorption properties from precipitated immune complexes for use in immunoadsorption procedures

Bioaffinity based immobilization of enzymes

Procedures that utilize the affinities of biomolecules and ligands for the immobilization of enzymes are gaining increasing acceptance in the construction of sensitive enzyme-based analytical devices as well as for other applications. The strong affinity of polyclonal/monoclonal antibodies for specific enzymes and those of lectins for glycoenzymes bearing appropriate oligosaccharides have been generally employed for the purpose. Potential of affinity pairs like cellulose-cellulose binding domain bearing enzymes and immobilized metal ionsurface histidine bearing enzymes has also been recognised. The bioaffinity based immobilization procedures usually yield preparations exhibiting high catalytic activity and improved stability against denaturation. Bioaffinity based immobilizations are usually reversible facilitating the reuse of support matrix, orient the enzymes favourably and offer the possibility of enzyme immobilization directly from partially pure enzyme preparations or even cell lysates. Enzyme lacking innate ability to bind to various affinity supports can be made to bind to them by chemically or genetically linking the enzymes with appropriate polypeptides/domains like the cellulose binding domain, protein A, histidine-rich peptides, single chain antibodies, etc.

Application of an ELISA-elution assay as a screening tool for dissociation of yolk antibody-antigen complexes

A modified enzyme-linked immunosorbent assay termed ELISA-elution assay was used as a screening tool to compare the efficiency of eluents for the dissociation of hen yolk immunoglobulin IgY bovine IgG complexes. The potential denaturing effects of the eluents were also monitored. Different buffers (pH 2.3-7.5), containing various types and concentrations of salts (NaCl, (NH4)2SO4 and MgCl2) as well as polyols (ethylene glycol (EG) and glycerol) were compared to the commonly reported glycine x HCl (pH 2.8) buffer and to a commercially available eluent, Actisep. Acidic pH buffers, Actisep and MgCl2 (3.5 M with EG or 4 M without EG) all successfully dissociated IgY from immobilized IgG. However, some denaturation was apparent using MgCl, and, to a lesser extent, Actisep. Furthermore, these same eluents demonstrated a diminished ability for liberating IgG from immobilized IgY(IgG). Information on eluent efficacy obtained by the ELISA-elution assays was applied to selectively isolate lower affinity antibodies for immunoaffinity column chromatography.

Two fetal antigens (FA-1 and FA-2) and endometrial proteins (PP12 and PP14) isolated from amniotic fluid; preliminary observations in fetal and maternal tissues

Rabbit antihuman antibodies were derived by the injection of fractions of second trimester amniotic fluid known to contain proteins of endometrial/decidual origin. Using standard separation and absorption procedures, two antibody preparations were generated which demonstrated specificities against two and three proteins, respectively, in line immunoelectrophoresis and crossed immunoelectrophoresis. Analysis against proteins of fetal, maternal, endometrial and placental origin revealed that the bispecific antiserum reacted only with placental protein 14 (PP14; also known as progestagen-dependent endometrial protein, PEP) and one other hitherto undescribed antigen referred to as Fetal Antigen 1 (FA-1) molecular mass 60 kDa; electrophoretic mobility: slow; alpha 1-alpha 2; fast, albumin. The trispecific antiserum demonstrated specifities against placental protein 12 (PP12), alpha-fetoprotein (AFP) and another previously undescribed antigen referred to as Fetal Antigen 2 (FA-2) molecular mass 35 and 140 kDa; electrophoretic mobility: albumin. Following purification, monospecific antisera against each of these proteins (with the exception of AFP) were derived in new rabbits. Maternal and fetal blood, amniotic fluid and aqueous extracts from endometrial/decidual and placental tissues were analysed in rocket immunoelectrophoresis using these antisera to examine the distribution in these tissues. The analyses demonstrated a pattern of distribution typical for proteins of endometrial/decidual origin in these compartments in the case of PP12 and PP14, but suggested that the primary source of origin of FA-1 and FA-2 may be the fetus.