[Studies on expression and function of human membrane cofactor protein in NIH3T3 cells].

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• The complement system is a crucial part of innate immunity.
• Membrane cofactor protein (MCP/CD46) regulates complement activation.
• Understanding MCP's function on heterologous cells is important for therapeutic applications.

Purpose of the Study:

• To investigate if recombinant human MCP expressed in NIH3T3 cells retains its complement inhibitory function.
• To assess the efficacy of MCP against different species' complement systems.

Main Methods:

• Construction of a recombinant human MCP expression plasmid (pcDNA3 MCP).
• Transfection of NIH3T3 cells using the calcium phosphate-DNA precipitate method.
• Selection of transfected cells using G418.
• Incubation of transfected cells with human, guinea pig, and rabbit serum to assess complement-mediated lysis.

Main Results:

• NIH3T3 cells transfected with MCP showed minimal lysis by human serum compared to control cells.
• Control cells transfected with the pcDNA3 vector were completely lysed by human serum.
• NIH3T3 cells expressing MCP were lysed by guinea pig and rabbit serum complement to the same extent as control cells.

Conclusions:

• Recombinant human MCP expressed in NIH3T3 cells successfully inhibits human complement activation.
• MCP's inhibitory function is specific to human complement and does not extend to guinea pig or rabbit complement.
• This study validates MCP as a potential therapeutic agent for complement-mediated diseases.