Rapid production of HIV-1 neutralizing antibodies in baculovirus infected insect cells

• VRC01 and b12 were expressed in Sf9 cells by baculoviruses co-infection.
• Purified b12Bac and VRC01Bac were fully assembled by disulphide bonds.
• The antigen reactivities of b12Bac and VRC01Bac were comparable to b12Mam.

Broadly neutralizing antibodies have been shown promise as prophylactic and therapeutic agents to provide passive protection against human immunodeficiency virus type 1 (HIV-1) infection. Such protein based microbicides are traditionally produced using mammalian cell expression system, which is not able to satisfy the increasing demand of these proteins in large scale. In this report, two of HIV-1 broadly neutralizing antibodies, b12 and VRC01, were successfully expressed in Sf9 insect cells by co-infection with baculoviruses respectively expressing the light and heavy chain of the antibodies. The purified antibodies are fully assembled as H2L2 (two heavy chains plus two light chains) heterodimer linked by covalent bonds. The b12 and VRC01 generated from insect cells reacted well to HIV-1 gp120, and their antigen binding ability is comparable to the mammalian cell-derived b12 as determined by ELISA and flow cytometry. Our data suggest that baculovirus/insect cell expression system can be utilized as an alternative to the mammalian expression system for the rapid production of HIV-1 broadly neutralizing antibodies.