Human monoclonal antibodies and monoclonal antibody multispecificity

Abstract

Summary The majority of human anti-tumour monoclonal antibodies (Mabs) isolated to date have been disappointing. Firstly, they react or cross react with intracellular cytoskeletal proteins or nuclear antigens and therefore are of limited value as blood borne agents. They are also generally of the IgM isotype and show relatively low intrinsic affinity for the primary epitope. Secondly, such Mabs can be generated from normal, non tumour bearing subjects at a frequency comparable to their production from tumour patients. This latter observation is true also for common autoantigens such as DNA and IgG since Mabs to these can also be generated from normal subjects in addition to autoimmune individuals. This article rationalises these observations in the context of the requirement for clinical use for human Mabs. It discusses the evidence that there is a potentially useful B cell response to be immortalised, and examines the consequences of the newly recognised phenomenon of monoclonal antibody multispecificity both on the methodology of their generation and on their subsequent use as imaging and therapeutic tools.

Complement-mediated in vitro bactericidal activity of monoclonal antibodies reactive with outer-surface-protein OspB of Borrelia burgdorferi

“…Borrelia bargdorferi monoclonal antibody (10-15 /.Lg/ml) supernatants were concentrated 10-fold by ammonium sulphate precipitation or protein-A column chromatography [16] and adjusted to the same equivalent concentration (50 txg/ml) before use. Serial two-fold dilution of hybridoma clone supernatants or immune ascites liquid (concentration of antibody: 11.2 mg/ml) were made in Eagle minimal essential medium.…”

Anti‐NeuGcGM3 reactivity: a possible role of natural antibodies and B‐1 cells in tumor immunosurveillance

“…Furthermore, due to its low affinity and high valency, the majority of IgM antibodies are polyreactive, allowing them to bind to a range of unrelated but phylogenetically conserved structures, such as nucleic acids, carbohydrates, and phospholipids . In fact, the importance of antitumor IgM was proven when a panel of human monoclonal antibodies were obtained from cancer patients’ B lymphocytes; most of the antibodies obtained that bound tumor cells were non‐affinity maturated, germline IgM antibodies that reacted with both extra‐ and intracellular antigens, such as carbohydrate structures, glycolipids, and cytoplasmatic as well as nuclear proteins …”

A Competitive Immunoassay for the Detection of Esterolytic Activity of Antibodies and Enzymes

“…In a typical kinetic assay for the detection of catalytic activity in a monoclonal antibody culture supernatant, the substrate concentration can be adjusted so as to make the catalyzed reaction work at maximum rate, while 1 M can be taken as the upper limit for the antibody's binding site concentration (26); thus, introducing in Eq. [2] the lower limit for v i previously calculated, it results that catalytic antibodies with a turnover number as low as k cat ϭ 5 ϫ 10 Ϫ7 s Ϫ1 can be detected by this competitive catELISA.…”