Related Experiment Video
Updated: Jun 13, 2026
An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
Immune profile diversity is achieved with synthetic TLR4 agonists combined with the RG1-VLP vaccine in mice
Rebecca L Matthews1, Nazneen Khan1, Bradley Beckman1
1Cancer ImmunoPrevention Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
Abstract:
The TLR4 (Toll-like receptor 4)-activating agonist MPLA (monophosphoryl lipid A) is a key component of the adjuvant systems AS01 and AS04, utilized in marketed preventive vaccines for several infectious pathogens. As MPLA is a biologically-derived product containing a mixture of several lipid A congeners with a 4' phosphoryl group and varying numbers of acyl chains with distinct activities, extensive efforts to refine its production and immunogenicity are ongoing; notably, the development of the BECC (Bacterial Enzymatic Combinatorial Chemistry) system in which bacteria express lipid A-modifying enzymes to produce a panoply of lipid A congeners. In an effort to characterize the adjuvant activity of these lipid A congeners, we compared biologically-derived and synthetic versions of BECC470 and BECC438 for adjuvant activity in BALB/c mice vaccinated with the HPV (Human papilloma virus) VLP-based vaccine, RG1-VLP. Synthetic BECC compounds compared favorably to biological versions and, in the case of synthetic BECC470, were routinely superior to their biologically-derived BECC counterpart. Synthetic BECC470-adjuvanted vaccines achieved broad spectrum immune activity characterized by elevated levels of total IgG and IgG2a subtype specific to HPV16 L1 VLPs and the HPV16 L2 peptide, as well as robust HPV16-neutralizing antibody titers. In addition, synthetic BECC470 promoted strong T cell responses to HPV16 L1, increased memory B cell frequency, and increased the T follicular helper cell (Tfh) population in draining lymph nodes. In contrast, the biologically-derived form of BECC470 induced an immune profile specific for highest levels of HPV16 L2-specific IgG2a as well as antibodies cross-neutralizing to HPV18 and HPV39. These data confirm that a synthetically-derived BECC compound can be combined with Alhydrogel to adjuvant the RG1-VLP vaccine as can biologically-derived BECC compounds and MPLA, albeit with subtly distinct immune responses. The distinctions in immune profiles triggered by these BECC compounds warrant further exploration for their capacity to activate TLR4 and modulate immune responses to vaccines.
Insights
Synthetic lipid A derivatives, like BECC470, show superior adjuvant activity in vaccines compared to biological versions. These synthetic compounds enhance immune responses against human papillomavirus (HPV), offering a promising avenue for vaccine development.
Area of Science:
- Immunology
- Vaccinology
- Biochemistry
Background:
- Monophosphoryl lipid A (MPLA) is a Toll-like receptor 4 (TLR4) agonist used in vaccines.
- The Bacterial Enzymatic Combinatorial Chemistry (BECC) system produces diverse lipid A congeners.
- Refining MPLA production and immunogenicity is crucial for vaccine development.
Purpose of the Study:
- To compare the adjuvant activity of biologically-derived and synthetic BECC lipid A congeners.
- To evaluate their immunogenicity in a human papillomavirus (HPV) vaccine model.
- To characterize the distinct immune responses elicited by different lipid A variants.
Main Methods:
- Vaccination of BALB/c mice with RG1-VLP vaccine and different BECC compounds (BECC470, BECC438).
- Comparison of biologically-derived versus synthetic versions of BECC compounds.
- Assessment of humoral and cellular immune responses, including antibody titers, T cell responses, and immune cell populations.
Main Results:
- Synthetic BECC compounds, particularly synthetic BECC470, demonstrated superior adjuvant activity compared to biological versions.
- Synthetic BECC470 induced broad immune activity, including high levels of IgG, IgG2a, neutralizing antibodies against HPV16, and robust T cell responses.
- Biologically-derived BECC470 elicited specific IgG2a responses and cross-neutralization against other HPV types.
Conclusions:
- Synthetically-derived BECC compounds can effectively adjuvant vaccines, similar to biologically-derived forms and MPLA.
- Distinct immune profiles are observed between synthetic and biological BECC compounds, warranting further investigation.
- These findings highlight the potential of synthetic lipid A derivatives for modulating vaccine-induced immune responses.
