Discovery of a chemical modification by citric acid in a recombinant monoclonal antibody.

Recombinant therapeutic monoclonal antibodies exhibit a high degree of heterogeneity that can arise from various post-translational modifications. The formulation for a protein product is to maintain a specific pH and to minimize further modifications. Generally Recognized as Safe (GRAS), citric acid is commonly used for formulation to maintain a pH at a range between 3 and 6 and is generally considered chemically inert.

Enhanced glyco-profiling by specific glycopeptide enrichment and complementary monolithic nano-LC (ZIC-HILIC/RP18e)/ESI-MS analysis.

Dedicated and specific sample preparation and adequate chromatographic resolution prior to MS are necessary for comprehensive and site-specific glycosylation analysis to compensate for high heterogeneity of protein glycosylation, low-abundance of specific glycoforms and ion-suppression effects caused by coelution of other peptides. This article describes a scheme for glycopeptide profiling, which comprises HILIC batch enrichment followed by complementary HILIC and RP-LC in 1-D and 2-D approaches. For reproducible and sensitive nano-LC/ESI-MS analysis, we used ZIC-HILIC and RP18e monolithic silica capillaries and assessed their retention characteristics and complementarity for glycopeptide separations.

Quantitative site-specific analysis of protein glycosylation by LC-MS using different glycopeptide-enrichment strategies.

A common technique for analysis of protein glycosylation is HPLC coupled to mass spectrometry (LC-MS). However, analysis is challenging due to a low abundance of glycopeptides in complex protein digests, microheterogeneity at the glycosylation site, ion suppression effects, and competition for ionization by coeluting peptides. Specific sample preparation is necessary for a comprehensive and site-specific glycosylation analysis by MS.

Peripheral INSL3 concentrations decline with age in a large population of Australian men.

The novel peptide hormone insulin-like peptide 3 (INSL3) is a major secretory product of the Leydig cells of the testis, and in adult men is secreted into the blood, giving rise to circulating concentrations ranging from 0.5 to 2.5 ng/mL.

Immunogenicity, efficacy and adverse events of adalimumab in RA patients.

To assess the immunogenicity of adalimumab, a human anti-TNF-alpha mAb, we evaluated the formation of antibodies to adalimumab, efficacy and adverse events among 15 patients with highly active rheumatoid arthritis. Four patients were treated with adalimumab as monotherapy, and 11 patients with concomitant DMARDs. Disease activity was measured by DAS28.