Specific Fab fragments recovered by phage display technique recognizing human spermatozoa

Area of Science:

• Immunology
• Biotechnology

Background:

• Human hybridoma cell lines often exhibit instability, leading to decreased and variable antibody production.
• Loss of antibody production can be attributed to inconsistent synthesis of heavy and light chains.

Purpose of the Study:

• To construct a phage display library of antibody fragments (Fabs) that recognize sperm surface antigens.
• To preserve the specificities of antibodies generated by human hybridomas using phage display technology.

Main Methods:

• Seven hybridoma cell lines producing antisperm antibodies were used as the source of mRNA.
• Complementary DNA fragments encoding kappa/lambda and gamma chains were cloned into a pComb3HSS phagemid vector.
• The constructed phage display library was panned against whole, unfixed sperm cells.

Main Results:

• Three positive clones were selected after four rounds of panning.
• Selected Fabs featured VH4 heavy chains; two clones (G28, K61) had VL2 lambda chains, and one (H43) had VK1 kappa chains.
• These Fabs showed similarities to antibodies targeting proteins involved in sperm motility and cell fusion, suggesting a potential role in infertility.

Conclusions:

• Phage display is a feasible technique for preserving specificities from human hybridomas.
• Recovered Fabs hold potential value for diagnostics, research, and contraceptive vaccine development.