Monoclonal anti-idiotypic antibodies that mimic the epitope on gp120 defined by anti-HIV-1 monoclonal antibody 0.5 beta

Immunization procedures for anti-idiotypic antibody induction in mice and rats

Anti-idiotypic antibodies (Ab2) mimicking antigens (Ags)-defined by antibodies (Ab1) directed to tumors or pathogens have elicited Ag-specific humoral, cellular and/or protective immunity in experimental animals and in humans. In immunizations of rodents with Ab1, factors such as animal species, form of Ab1 and choice of adjuvant are crucial for the successful induction of Ab2 as candidate vaccines against tumors and pathogens. Here we survey the outcome of 362 fusion events (each event representing one animal), using nine immunization schedules in mice and seven schedules in rats and including 10 different Ab1 directed against human tumor- and immunodeficiency virus (HIV-1)-associated Ags. Ab1 IgG or F(ab')2 were administered uncoupled or coupled to keyhole limpet hemocyanin (KLH). As adjuvants, complete and incomplete Freund's adjuvant (CFA/IFA), lipid A, aluminum hydroxide, TiterMax or vaccinia virus were used. In syngeneic immunizations with murine Ab1 in mice, F(ab')2 coupled to KLH and emulsified in CFA/IFA preferentially induced Ab2 mimicking tumor or HIV-1 associated epitopes. In xenogeneic immunizations with mouse Ab1 in rats, various forms of Ab1 and adjuvants successfully induced Ab2 mimicking tumor Ags.

Functional mimicry of an anti-idiotypic antibody to nominal antigen on cellular response

One concept for immune therapy of cancer involves induction of antigen mimic antibodies to trigger the immune system into a response against the tumor cells. Anti-idiotypic antibodies (Ab2) directed against the antigen-combining site of other antibodies (Ab1) may functionally and even structurally mimic antigen and induce anti-anti-idiotypic immune response. We report here the generation of murine monoclonal antibody (mAb) WJ02 (Ab2) raised against the murine monoclonal immunoglobulin MJ01 (Ab1), which defines ovarian cancer antigen CA125. In enzyme immunoassays the binding of Ab2 to the variable region of Ab1 could be inhibited by CA125. In addition, the mimicry of mAb WJ02 to CA125 on cellular immune response was detected by human peripheral blood cells. The T cells primed by mAb WJ02 or CA125 proliferated in the presence of CA125 or mAb WJ02, respectively. Furthermore, T cells specific to mAb WJ02 could lyse ovarian cancer cells OVCAR-3 that express CA125. Finally, we proved that a patient immunized with mAb MJ01 could induce T cells that recognize mAb WJ02. In summary, we conclude that mAb WJ02 mimics CA125 on cellular response and such functional mimicry is one of the most important criteria to select Ab2 for cancer therapy.

Anti-idiotypic antibody to the V3 domain of gp120 binds to vimentin: a possible role of intermediate filaments in the early steps of HIV-1 infection cycle

Although the CD4 molecule is the major cellular receptor for human immunodeficiency virus (HIV), several lines of evidence suggest participation of additional molecules that are engaged after the binding of HIV to the CD4 receptor and that may facilitate viral entry into the target cell. Some of the post-CD4 binding, perfusion events involve the third hypervariable region (V3 loop) of the viral envelope protein gp120. To identify cellular proteins that interact with the V3 loop, we chose as a probe an antiidiotypic monoclonal antibody (MAb), anti-id2, which was prepared against the neutralizing MAb 110.4 that binds the V3 domain in the envelope glycoprotein gp120 of the LAI isolate of HIV-1. Anti-id2 reacted specifically with a 55- to 60-kDa protein in human T cell and monocytoid cell lines, and in a mouse melanoma cell line. This protein was identified immunologically and by protein sequence analysis as vimentin, an intermediate filament protein of lymphoid and other cells of mesodermal origin. Antiserum raised against vimentin inhibited nuclear translocation of HIV-1 DNA following infection of monocytes and CD4+ T cells with live virus, and reduced the amount of HIV-1 gag-specific RNA in the nuclei of monocytes following inoculation with HIV-1 pseudovirions. These data suggest that vimentin may participate in the early steps of HIV-1 replication, perhaps during the uptake of HIV-1 preintegration complexes into the nuclear compartment.