Interaction of the octapeptide angiotensin II with a high-affinity single-chain Fv and with peptides derived from the antibody paratope.

The amino-acid sequence of the very high-affinity anti-angiotensin II monoclonal antibody 4D8 was predicted from the nucleotide sequence of the heavy and light chain variable genes. The single-chain variable fragment (scFv) was constructed and expressed in Escherichia coli as a soluble protein and at the surface of the filamentous M13 phage and was compared with the full-length antibody (Ab). The scFv showed the same specificity profile and affinity constant as the intact antibody (5.

Selective recognition of M235T angiotensinogen variants and their determination in human plasma by monoclonal antibody-based immunoanalysis.

The common M235T mutation of human angiotensinogen has been shown to be associated with a 10-20% increase in plasma angiotensinOgen level and increased frequency of essential and pregnancy-induced hypertension. The detection of such a common factor in the plasma of individuals at risk could be a useful tool for modern molecular-based medicine. The recognition of M235T variants was investigated using four monoclonal antibodies (mAbs) directed against human angiotensinogen; two immunometric assays were developed.

New monoclonal antibodies directed against the propart segment of human prorenin as a tool for the exploration of prorenin conformation.

Six monoclonal antibodies (MAbs) directed against human prorenin were produced by immunizing BALB/c mice with a peptide corresponding to the sequence (-17 to +9) of prorenin. The new MAbs were screened for their ability to first bind to the immobilized peptide and then to prorenin previously captured by an anti-total renin MAb. The specificity of the MAbs was confirmed by the total lack of binding to active renin.

Direct, simplified, and sensitive assay of angiotensin II in plasma extracts performed with a high-affinity monoclonal antibody.

A very simple, fast, and sensitive RIA of angiotensin (Ang) II has been developed, based on a monoclonal antibody with high affinity and specificity, making possible the direct measurement of circulating Ang II in human plasma after solid-phase extraction. The purified monoclonal antibody 4D8 has an association constant of 1.3 x 10(11) L/mol with Ang II and a cross-reactivity of < 1% for Ang I.

Two-site direct immunoassay specific for active renin.

A sensitive immunoradiometric assay, without an enzymatic step and specific for active human renin, was developed with use of two monoclonal antibodies (MAbs). In this assay system, the first MAb was coupled to magnetic beads (Magnogel); the second one, directed against the active form of the enzyme, was radiolabeled with 125I. The specificity of this assay was demonstrated in experiments measuring the active plasma renin concentration in the presence or absence of inactive renin.