Cooperation between human DAF and CD59 in protecting cells from human complement-mediated lysis

Area of Science:

• Immunology
• Biotechnology
• Transplantation Immunology

Background:

• Complement (C) regulatory proteins, decay accelerating factor (DAF, CD55) and CD59, protect host cells from C-mediated damage via distinct mechanisms.
• Host C-induced xenograft hyperacute rejection is a significant barrier in transplantation.
• Co-expression of DAF and CD59 presents a potential strategy to mitigate this rejection.

Purpose of the Study:

• To construct a recombinant expression vector for co-expressing DAF and CD59.
• To generate and validate stable cell lines expressing these proteins.
• To evaluate the protective efficacy of co-expressed DAF and CD59 against complement-mediated damage.

Main Methods:

• Construction of a recombinant expression vector encoding DAF and CD59 cDNA.
• Generation of stable cell lines using G418 selection.
• Confirmation of gene integration and co-expression via PCR, RT-PCR, and Western blot.
• Assessment of cell protection using human C-mediated cytolysis assays.

Main Results:

• Stable cell lines expressing DAF, CD59, or both were successfully generated.
• PCR, RT-PCR, and Western blot confirmed extraneous gene integration and co-expression.
• Cells co-expressing DAF and CD59 demonstrated significantly enhanced protection against C-mediated damage compared to cells expressing either protein alone.
• NIH/3T3 cells transfected with pcDNA3-CD59DAF-DP showed the highest level of protection.

Conclusions:

• The developed construct and stable cell lines represent an effective strategy for co-expressing DAF and CD59.
• Synchronous expression of human CD59 and DAF provides superior protection against complement-mediated damage.
• This approach holds promise for overcoming C-mediated damage in cellular therapies and potentially in animal models, addressing xenograft rejection challenges.