Styrene Maleic Acid Lipid Particles Prepared from Mycobacterium tuberculosis Plasma Membrane can Potentially Induce Innate and Adaptive Immune Responses in Healthy Individuals of a Tuberculosis Hyperendemic Region.

Emerging paradigm suggests that an effective vaccine against tuberculosis (TB) should elicit the necessary innate and adaptive immune responses against Mycobacterium tuberculosis (Mtb). We previously reported that styrene-maleic acid lipid particles (SMALPs) prepared from Mtb plasma membrane (MtM) contain proteins, lipoproteins, and glycolipids capable of inducing these responses in humans. Here, we have evaluated the responses induced by MtM and MtM-SMALPs in fifteen donors of a cohort of healthcare workers from north India. Key cytokines associated with innate (IL-6, TNF-α and IL-1β) and adaptive (IFN-γ) immune responses were assayed by ELISA in the supernatants of blood cultures, which were also used for the determination of T cell proliferative responses by flow cytometry. Serum antibody levels assayed by ELISA served as additional markers of adaptive immunity. MtM-SMALPs enhanced the production of all four cytokines in a concentration-dependent manner whereas higher concentrations of MtM suppressed these responses, significantly for IL-1β. Antibody responses also diverged, with IgM predominating against MtM and IgG against MtM-SMALPs, although overall antibody levels against MtM-SMALPs were low. Together, these findings indicate that MtM-SMALPs are enriched in constituents capable of eliciting the innate and adaptive immunity against Mtb and support further evaluation of SMALPs as a potential vaccine platform.