Production and characterization of human anti-V3 monoclonal antibodies from the cells of HIV-1 infected Indian donors

Hybridoma technology a versatile method for isolation of monoclonal antibodies, its applicability across species, limitations, advancement and future perspectives

The advancements in technology and manufacturing processes have allowed the development of new derivatives, biosimilar or advanced improved versions for approved antibodies each year for treatment regimen. There are more than 700 antibody-based molecules that are in different stages of phase I/II/ III clinical trials targeting new unique targets. To date, approximately more than 80 monoclonal antibodies (mAbs) have been approved. A total of 7 novel antibody therapeutics had been granted the first approval either in the United States or European Union in the year 2019, representing approximately 20% of the total number of approved drugs. Most of these licenced mAbs or their derivatives are either of hybridoma origin or their improvised engineered versions. Even with the recent development of high throughput mAb generation technologies, hybridoma is the most favoured method due to its indigenous nature to preserve natural cognate antibody pairing information and preserves innate functions of immune cells. The recent advent of antibody engineering technology has superseded the species level barriers and has shown success in isolation of hybridoma across phylogenetically distinct species. This has led to the isolation of monoclonal antibodies against human targets that are conserved and non-immunogenic in the rodent. In this review, we have discussed in detail about hybridoma technology, its expansion towards different animal species, the importance of antibodies isolated from different animal sources that are useful in biological applications, advantages, and limitations. This review also summarizes the challenges and recent progress associated with hybridoma development, and how it has been overcome in these years to provide new insights for the isolation of mAbs.

Difficult-to-neutralize global HIV-1 isolates are neutralized by antibodies targeting open envelope conformations

The HIV-1 envelope (Env) is the target for neutralizing antibodies and exists on the surface of virions in open or closed conformations. Difficult-to-neutralize viruses (tier 2) express Env in a closed conformation antigenic for broadly neutralizing antibodies (bnAbs) but not for third variable region (V3) antibodies. Here we show that select V3 macaque antibodies elicited by Env vaccination can neutralize 26% of otherwise tier 2 HIV-1 isolates in standardized virus panels. The V3 antibodies only bound to Env in its open conformation. Thus, Envs on tier 2 viruses sample a state where the V3 loop is not in its closed conformation position. Envelope second variable region length, glycosylation sites and V3 amino acids were signatures of neutralization sensitivity. This study determined that open conformations of Env with V3 exposed are present on a subset of otherwise neutralization-resistant virions, therefore neutralization of tier 2 HIV-1 does not always indicate bnAb induction.

Phage display antibody libraries: A robust approach for generation of recombinant human monoclonal antibodies

Monoclonal antibodies (mAbs) and their derivatives have achieved remarkable success as medicine, targeting both diagnostic and therapeutic applications associated with communicable and non-communicable diseases. In the last 3 to 4 decades, tremendous success has been manifested in the field of cancer therapy, autoimmune diseases, cardiovascular and infectious diseases. MAbs are the fastest growing class of biopharmaceuticals, with more than 25 derivatives are in clinical use and 7 of these have been isolated through phage display technology. Phage display technology has gained impetus in the field of medical and health sciences, as a large repertoire of diverse recombinant antibodies, targeting various antigens have been generated in a short span of time. A prominent number of phage display derived antibodies are already approved for therapy and significant numbers are currently in clinical trials. In this review we have discussed the various strategies employed for generation of monoclonal antibodies; their advantages, limitations and potential therapeutic applications. We also discuss the potential of phage display antibody libraries in isolation of monoclonal antibodies.

Prime/boost immunization with HIV-1 MPER-V3 fusion construct enhances humoral and cellular immune responses

Development of an effective vaccine against HIV-1 infection is a main concern in worldwide. A potent vaccine for HIV-1 requires the induction and maintenance of both humoral and cellular immunity. In this study, the levels of humoral and cellular immune responses were compared using MPER-V3 injection in three immunization strategies such as DNA/DNA, peptide/peptide, and DNA/peptide (prime-boost). MPG peptide and Montanide 720 were used as a DNA delivery system, and as a peptide adjuvant, respectively. Our results demonstrated that MPG forms stable non-covalent nanoparticles with plasmid DNA at N/P ratio of 10:1 (∼ 110-130 nm). The in vitro transfection efficiency of MPER-V3 DNA using MPG was comparable with lipofectamine and turbofect reagents as a common delivery system. In vivo prime-boost immunization using HIV-1 MPER-V3 could significantly enhance humoral and cellular immune responses as compared to control groups. The mixture of IgG1 and IgG2a was observed for each strategy, but IFN-γ production was significantly higher in prime-boost and peptide immunizations than that in DNA immunizations, inducing Th1 response. Moreover, our data showed that prime immunization with low dose of the nanoparticles (MPER-V3 DNA: MPG at ratio of 1:10) followed by MPER-V3 peptide drives T cell responses towards a Th1-type similar to high dose of the naked DNA prime/peptide boost immunization. Generally, the prime-boost strategy could improve both immune responses against MPER and especially V3 peptides suggesting its application as a promising HIV vaccine candidate in future.