Brett, P. J. | Search bioRxiv

bioRxiv2026

Subunit Vaccination Using Atomic Layering Thermostable Antigen and Adjuvant (ALTA(R)) Platform Elicits Enhanced Humoral and Cellular Immune Responses

AbstractCreating effective and thermostable vaccines is of significant relevance for public health. The Atomic Layering Thermostable Antigen and Adjuvant (ALTA(R)) platform combines spray drying to stabilize antigens in a sugar matrix followed by coating with atomic layer deposition (ALD) for temporal control over in vivo release. While these technologies have shown preliminary promise for different vaccine antigens, further characterizations of the immune response to ALTA(R) formulated antigens are still needed. Here, the immune response to ALTA(R) formulated antigens is described and compared to a set of adjuvanted liquid vaccine formulations that included Alhydrogel(R), AddaVax, and Alhydrogel(R)+CpG. The humoral and cell-mediated responses were measured by ELISA and flow cytometry. Increased and lasting antigen-specific antibody titers following administration of ALTA(R) containing ovalbumin (OVA) demonstrated robust and durable humoral response. Furthermore, ALTA(R) injected mice produced both IgG2c and IgG1 indicating a balanced Th1/Th2 response. Importantly, ALTA(R) OVA elicited robust humoral response at lower doses of aluminum than Alhydrogel(R). The most striking difference between ALTA(R) and the liquid vaccine formulations tested was a greater OVA-specific CD8+ T cell response observed at all antigen doses tested. Mechanistically, antigen encapsulation within ALTA(R) particles was critical for antibody production and CD8+ T cell responses as well as antigen capture by antigen-presenting cells (APCs) at the site of injection and draining lymph nodes. To test these concepts in a more physiological application, protein and polysaccharide vaccine antigens derived from a facultative intracellular bacterium Burkholderia pseudomallei, the causative agent of melioidosis, were formulated using the ALTA(R) platform. Compared to liquid vaccine formulations, ALTA(R) immunized mice showed enhanced antigen-specific antibody production and IFN-{gamma} secreting T cell responses using lower adjuvant doses of aluminum and CpG. Overall, ALTA(R) formulated protein and polysaccharide antigens elicited strong humoral and cell-mediated immunity suggesting potential broad applicability of the platform to vaccines against various diseases, including against cancer and infections from intracellular pathogens.

immunology↗

bioRxiv2018

Caprine humoral response to Burkholderia pseudomallei antigens during acute melioidosis from aerosol exposure

Burkholderia pseudomallei causes melioidosis, a common source of pneumonia and sepsis in Southeast Asia and Northern Australia, that results in high mortality rates. A caprine melioidosis model of aerosol infection that leads to a systemic infection has the potential to characterize the humoral immune response. This could help identify immunogenic proteins for new diagnostics and vaccine candidates. Outbred goats may more accurately mimic human infection, in contrast to the inbred mouse models used to date. B. pseudomallei infection was delivered as an intratracheal aerosol. Antigenic protein profiling was generated from the infecting strain MSHR511. Humoral immune responses were analyzed by ELISA and western blot, and the antigenic proteins were identified by mass spectrometry. Throughout the course of the infection the assay results demonstrated a much greater humoral response with IgG antibodies, in both breadth and quantity, compared to IgM antibodies. Pre-infection sera showed multiple immunogenic proteins already reactive for IgG (7-20) and IgM (0-12) in most of the goats despite no previous exposure to B. pseudomallei. After infection, the number of IgG reactive proteins showed a marked increase as the disease progressed. Early stage infection (day 7) showed immune reaction to chaperone proteins (GroEL, EF-Tu, and DnaK). These three proteins were detected in all serum samples after infection, with GroEL immunogenically dominant. Seven common reactive antigens were selected for further analysis using ELISA. The heat shock protein GroEL1 elicited the strongest goat antibody immune response compared to the other six antigens. Most of the six antigens showed the peak IgM reactivity at day 14, whereas the IgG reactivity increased further as the disease progressed. An overall MSHR511 proteomic comparison between the goat model and human sera showed that many immune reactive proteins are common between humans and goats with melioidosis.\n\nAuthor SummaryB. pseudomallei infection, the causative agent of melioidosis, results in severe disseminated or localized infections. A systemic study of the humoral immune response to B. pseudomallei infection using the B. pseudomallei aerosol caprine model would help understand the detectable antigenic proteins as the infection progresses. To study the immune response, IgG and IgM antibody responses to whole cell lysate proteins were identified and analyzed. Antigenic carbohydrates were also studied. From the results, this study suggests that the caprine humoral immune response to aerosolized B. pseudomallei has similarities to human melioidosis and may facilitate the analysis of the temporal antibody responses. In addition, commonly detected immunogenic proteins may be used as biomarkers for the future point of care (POC) diagnostics.

immunology↗