A novel neuroendocrine cell surface glycoprotein: identification, isolation, and initial characterization

Area of Science:

• Immunology
• Cell Biology
• Endocrinology

Background:

• Human pancreatic islet cells express differentiation antigens crucial for understanding islet cell function and autoimmune diseases.
• Monoclonal antibodies (MAbs) are valuable tools for identifying and characterizing cell-specific antigens.

Purpose of the Study:

• To characterize a novel differentiation antigen recognized by MAbs HISL-5, -9, and -14 on human pancreatic islet cells.
• To investigate the expression profile of this antigen in other endocrine and non-endocrine tissues.
• To determine the biochemical properties of the identified antigen.

Main Methods:

• Generation of murine monoclonal antibodies (MAbs) against human pancreatic islet cells.
• Immunofluorescence staining of viable cells and tissue sections.
• Biochemical characterization including sensitivity to proteases, oxidants, and solvents.
• Immunoaffinity chromatography for antigen purification.

Main Results:

• MAbs HISL-5, -9, and -14 recognize a cell surface antigen on all human pancreatic islet endocrine cell subtypes.
• The antigen is minimally expressed on exocrine acinar, vascular, and stromal cells.
• Expression is also detected on thyroid follicular cells, parathyroid chief cells, and anterior pituitary cells.
• The antigen is trypsin-sensitive, periodate-resistant, and chloroform-methanol resistant.
• Purification revealed the antigen to be a 100 K glycoprotein.

Conclusions:

• A novel 100 K glycoprotein antigen is identified on human pancreatic islet cells using MAbs HISL-5, -9, and -14.
• The antigen's presence on multiple endocrine cell types suggests its potential involvement in organ-specific autoimmune disorders.
• This antigen serves as a potential biomarker for pancreatic islet cells and related autoimmune conditions.