Changes in cell surface glycoprotein expression during differentiation of human keratinocytes

Area of Science:

• Cell Biology
• Dermatology
• Immunology

Background:

• Human epidermis comprises keratinocytes that undergo differentiation.
• Cell surface glycoproteins play crucial roles in epidermal structure and function.
• Understanding antigen expression during keratinocyte differentiation is vital for dermatological research.

Purpose of the Study:

• To characterize the expression and synthesis of six defined cell surface glycoproteins on human epidermal cells.
• To compare glycoprotein synthesis in fresh epidermis versus short-term primary epidermal cultures.
• To propose a model for surface antigenic changes during in vivo keratinocyte differentiation.

Main Methods:

• Monoclonal antibody definition of six cell surface glycoproteins.
• Immunohistochemical analysis on human epidermal tissue sections.
• [35S]methionine metabolic labeling to compare glycoprotein synthesis in fresh epidermis and cultured cells.

Main Results:

• Three glycoproteins (J143, T43, H99) were localized to the basal cell layer, while three (T179, T16, BT15) were found in maturing keratinocytes.
• Significant differences in synthesis rates were observed for J143, T43, and BT15 between fresh epidermis and cultured cells.
• Synthesis of H99, T179, and T16 remained relatively unchanged in cultured epidermal cells.

Conclusions:

• Keratinocyte differentiation involves dynamic changes in cell surface glycoprotein expression and synthesis.
• Primary epidermal cultures exhibit altered synthesis patterns for specific glycoproteins compared to fresh tissue.
• A model for surface antigenic changes during keratinocyte differentiation in vivo is proposed based on these findings.